View source for Scratch (programming language)

{{Short description|Programming language learning environment}}
{{about|the programming language|other uses|Scratch (disambiguation)}}
{{pp-semi-indef|small=yes}}
{{Multiple issues|{{primary sources|date=February 2022}}
{{user-generated|date=October 2023}}
{{unreliable sources|date=May 2025}}}}
{{Use dmy dates|date=February 2022}}

{{Infobox programming language
| logo = Scratchlogo.svg
| logo caption = Logo used since 16 October 2015
| logo_alt = Scratch logo
| screenshot = Scratch editor screenshot.png
| screenshot caption = Scratch 3.0 editor
| paradigm = [[Event-driven programming|Event-driven]], [[Visual programming language|block-based]] programming language
| year = {{plainlist|
* {{Start date and age|2003|10|11|df=y}} (prototype Scratch 0.1)<ref>{{cite conference|first1=John|last1=Maloney|first2=Leo|last2=Burd|first3=Yasmin|last3=Kafai|first4=Natalie|last4=Rusk|first5=Brian|last5=Silverman|first6=Mitchel|last6=Resnick|title=Scratch: A Sneak Preview|date=29-30 January 2004|url=https://www.researchgate.net/publication/221338134|via=ResearchGate|at=Section 6: Project status and next steps|conference=Second International Conference on Creating, Connecting and Collaborating through Computing|doi=10.1109/C5.2004.33}}</ref>
* {{Start date and age|2007|5|15|df=y}} (Scratch 1.0)<ref>{{cite web|url=https://en.scratch-wiki.info/wiki/Scratch_Timeline#May|title=Scratch Timeline – Scratch Wiki|website=en.scratch-wiki.info}}</ref>
* {{Start date and age|2013|5|9|df=y}} (Scratch 2.0)
* {{Start date and age|2019|1|2|df=y}} (Scratch 3.0)
}}
| latest_release_version = {{plainlist|
* Scratch 3.0 (online editor) / {{Start date and age|2019|1|2|df=y}}
* Scratch 3.29.1 (offline editor) / {{Start date and age|2022|2|27|df=y}}
}}
| developer = [[Scratch Foundation]]
| discontinued = No|
| influenced by = [[Logo (programming language)|Logo]], [[Smalltalk]], [[HyperCard]], [[StarLogo]], [[AgentSheets]], [[AgentCubes]], [[Etoys (programming language)|Etoys]], [[Snap! (programming language)|Snap''!'']]
| influenced = [[Catrobat]],<ref>{{cite web|url=https://catrobat.org/|title=Catrobat Home|website=catrobat.org}}</ref>
 [[ScratchJr]],<ref>{{cite web|url=https://scratchjr.org/|title=ScratchJr – Home|website=scratchjr.org}}</ref> [[Snap! (programming language)|Snap''!'']],<ref>{{cite web|url=https://snap.berkeley.edu/|title=Snap! Build Your Own Blocks|website=snap.berkeley.edu}}</ref> [[mBlock]], [[Turtlestitch]]
| programming language = [[Squeak]] (Scratch 1.x)<br />[[ActionScript]] (Scratch 2.0)<ref name="david lee scratch 3.0">{{cite web|last=Lee |first=David| date=2018-12-28| title=What you need to know about Scratch 3.0|url=https://www.computhink.com.sg/what-you-need-to-know-about-scratch-3-0/|access-date=2024-02-09 |website=Computhink}}</ref><br />[[HTML5]], [[JavaScript]] (Scratch 3.0)<ref name="david lee scratch 3.0" /><ref name="flash to js">{{Cite web |last=Frang |first=Corey |date=2019-02-28 |title=Porting Scratch from Flash to JavaScript: Performance, Interoperability and Extensions |url=https://bocoup.com/blog/porting-scratch-from-flash-to-javascript-performance-interoperability-and-extensions |access-date=2024-02-09 |website=bocoup}}</ref>
| operating system = [[Microsoft Windows]], [[macOS]], [[Linux]] (via renderer), [[HTML5]] (via web browser), [[iOS]], [[iPadOS]], and [[Android (operating system)|Android]].
| license = {{plainlist|*
[[AGPLv3|GNU Affero General Public License]] (Scratch 3.0)<ref>{{cite web |title=Strengthening Our Commitment to Free and Open Source Software |url=https://www.scratchfoundation.org/open-source-license |website=Scratch Foundation |access-date=6 December 2024}}</ref> 
*[[BSD licenses|BSD 3-Clause]] (earlier versions of 3.0),
*[[GNU General Public License|GPLv2]] and Scratch Source Code License (1.x)}}
| file_ext = .sb, .sprite (Scratch 1.x)<br />.sb2, .sprite2 (Scratch 2.0)<br />.sb3, .sprite3 (Scratch 3.0)
| website = {{URL|https://scratch.mit.edu/}}
}}

'''Scratch''' is a [[High-level programming language|high-level]], block-based [[visual programming language]] and website aimed primarily at children as an educational tool, with a target audience of ages 8 to 16.<ref>{{Cite web |title=KS1 / KS2 Computing: Programming a robot crocodile |url=https://www.bbc.co.uk/teach/class-clips-video/articles/z4hpy9q |access-date=2024-12-08 |website=BBC Teach |language=en-GB}}</ref><ref name=":3">{{cite web |last=scratch |first=scratch |date=11 October 2022 |title=Scratch – About |url=https://scratch.mit.edu/about#:~:text=but%20is%20used%20by%20people%20of%20all%20ages. |website=scratch.mit.edu}}</ref> Users on the site can create projects on the website using a block-like interface. Scratch was conceived and designed through collaborative [[National Science Foundation]] grants awarded to [[Mitchel Resnick]] and [[Yasmin Kafai]].<ref name=":0" /> Scratch is developed by the [[MIT Media Lab]] and has been translated into 70+ languages, being used in most parts of the world. Scratch is taught and used in after-school centers, schools, and colleges, as well as other public knowledge institutions. As of 15 February 2023, community statistics on the language's official website show more than 123 million projects shared by over 103 million users, and more than 95 million monthly website visits.<ref name="statistics">{{cite web |title=Community statistics at a glance |url=https://scratch.mit.edu/statistics/ |url-status=live |archive-url=https://web.archive.org/web/20160406023520/https://scratch.mit.edu/statistics/ |archive-date=6 April 2016 |access-date=18 May 2019 |website=scratch.mit.edu}}</ref> Overall, more than 1.15 billion projects have been created in total, with the site reaching its one billionth project on April 12th, 2024.

Scratch takes its name from a technique used by [[disk jockey]]s called "[[scratching]]", where vinyl records are clipped together and manipulated on a turntable to produce different sound effects and music. Like scratching, the website lets users mix together different media (including graphics, sound, and other programs) in creative ways by creating and "remixing" projects, like [[video games]], [[animations]], [[music]], and [[simulations]].<ref>{{cite news |url=https://news.mit.edu/2007/resnick-scratch |title=Creating from Scratch |newspaper=MIT News |first=Stephanie |last=Schorow |date=14 May 2007 |access-date=18 May 2019 |archive-url=https://web.archive.org/web/20181013032644/http://news.mit.edu/2007/resnick-scratch |archive-date=13 October 2018 |url-status=live }}</ref>

== Scratch 3.0 ==
=== User interface ===
[[File:Dialogo scratch Best Friends 1.png|thumb|A program to change the background and make a sprite speak]]
The Scratch interface is divided into three main sections: a ''stage area'', ''block palette'', and a coding area to place and arrange the blocks into scripts that can be run by pressing the green flag or clicking on the code itself. Users may also create their own code blocks, which will appear in the "My Blocks" section.

The ''stage area'' features the results (e.g., [[animation]]s, [[turtle graphics]], either in a small or normal size, with a full-screen option also available) and all [[Sprite (computer graphics)|sprites]]' thumbnails being listed in the bottom area. The stage uses x and y [[Coordinate system|coordinates]], with 0,0 being the stage center.<ref name="LearnToProgram" />

With a sprite selected at the bottom of the staging area, blocks of code can be applied by dragging them from the block palette into the coding area. The Costumes tab allows users to change the look of the sprite with a [[Vector graphics|vector]] and [[bitmap]] editor in order to create various effects, including animation.<ref name="LearnToProgram" /> The Sounds tab allows attaching sounds and music to a sprite.<ref name="sciencebuddies.org" />

When creating sprites and also backgrounds, users can draw their own sprites manually,<ref name="LearnToProgram" /> choose a sprite from the library, or upload an image.<ref name="sciencebuddies.org">{{cite web |title=Science Buddies: Scratch User Guide: Installing & Getting Started with Scratch |url=https://www.sciencebuddies.org/science-fair-projects/references/installing-getting-started-with-scratch |website=ScienceBuddies.org |access-date=2019-05-18 |archive-url=https://web.archive.org/web/20190518123252/https://www.sciencebuddies.org/science-fair-projects/references/installing-getting-started-with-scratch |archive-date=2019-05-18 |url-status=live }}</ref>

The table below shows the categories of the programming blocks:
{| class="wikitable"
|+Block categories in Scratch
! colspan="2" | Category
! Notes
|-
| style="background:#4c97ff;" |
| Motion
| Movements of sprites, like angles and directions. 
|-
| style="background:#9966ff;" |
| Looks
| Controls the visuals of the sprite.
|-
| style="background:#cf5acf;" |
| Sound
| Plays [[audio files]] and effects.
|-
| style="background:#ffbf00;" |
| Events
| Event handlers and broadcasters.
|-
| style="background:#ffab19;" |
| Control
| Conditionals, loops, and cloning. 
|-
| style="background:#5cb1d6;" |
| Sensing
| [[Sprite (computer graphics)|Sprites]] can interact with other sprites, the mouse pointer, and the backdrop.
|-
| style="background:#52b55a;" |
| Operators
| Mathematical [[operator (computer programming)|operators]], conjunctions, and comparisons .
|-
| style="background:#ff8c1a;" |
| Variables
| Blocks to access and set [[variable (computer science)|variables]]. Cloud variables are synced across all running versions of the project.
|-
| style="background:#ff4c00;" |
| Lists
| Blocks to access and interact with [[Array (data type)|lists]].
|-
| style="background:#ff4d88;" |
| My Blocks
| User-defined [[Subroutine|functions]], accessible as blocks. They can have inputs and have the option to run without a screen refresh.
|-
| style="background:#0fbd8c;" |
| Extensions
| Extra categories (e.g. Pen, Music) of blocks that can be added to a project at any time.
|}

=== Offline editing ===
[[File:Scratch Beginner Scripts.png|alt=One of the 4 different scripts for the getting started built-in tutorial.|thumb|Four different scripts for the getting started built-in tutorial.]]
[[File:Example script of asking the user thier name, and it says "Hello, (name)!".png|alt=A coded example, using the ask block for the users' name, then responding with it,|thumb|A coded example, using the ask block for the users' name, then responding with it,]]
An offline "Desktop Editor" for Scratch 3.0 is available for Microsoft [[Windows 10]] and above in the Microsoft Store, Apple's macOS, ChromeOS, and Android;<ref>{{cite web |title=Scratch Desktop |url=https://scratch.mit.edu/download |access-date=19 September 2019}}</ref> this allows the creation and playing of Scratch programs offline. The offline editor can also be downloaded in previous versions, such as Scratch 2.0 and Scratch 1.4 (an archive of older versions is found [https://scratcharchive.naleksuh.com/ here]).

=== Extensions ===
In Scratch, extensions add extra blocks and features that can be used in projects. In Scratch 2.0, the extensions were all hardware-based and Pen was a normal category. Software-based extensions were added in Scratch 3.0, such as text-to-speech voices, along with some new hardware-based extensions like the [[Micro Bit|micro:bit]]. The extensions are listed below.

[[File:Scratch Extensions Page.png|thumb|389x389px|An example of the Scratch 3 Extensions Page.]]

==== Physical ====
* [[Lego Mindstorms EV3|LEGO Mindstorms EV3]] – Control motors and receive sensor data from the Lego Mindstorms EV3
* [[Makey Makey]] – Use Makey Makey to control projects
* [[Lego Education#WeDo|LEGO Education WeDo 2.0]] – control motors and receive sensor data from the Lego WeDo
* [[Micro Bit|micro:bit]] – Use of a micro:bit to control projects
* LEGO BOOST – Bring robotic creations to life
* Go Direct Force & Acceleration – Sense pull, push, motion, and spin

==== Digital ====
Many of the digital extensions in Scratch 3.0 used to be regular block categories that were moved to the extensions section to reduce clutter. These include:
* Music – Play digital instruments (drums, trumpets, violins, pianos, and more). Previously part of the Sound category.
* Pen – Draw on the Stage with a variety of thicknesses and color. Previously a normal block category.
* Video Sensing – [[Optical flow|Detect motion]] with the camera. Previously in the Sensing category.

New digital extensions have also been added in collaborations with commercial companies. These include:
* Text to Speech – Converts words in a text into voice output, especially having an option for languages (variety of voices, supplied by Amazon)
* Translate – Uses [[Google Translate]] to translate text from one language into a variety of other languages, including Arabic, Chinese, Dutch, English, French, Greek, Norwegian, and Japanese
* Makey Makey – Options for better key pressing and press multiple keys in order. You can grab a join block if you want more control on the extension.
A paper published in 2019 by [[New York University|NYU]] argues and illustrates, for coding music with Scratch, "that the music and sound blocks as currently implemented in Scratch may limit and frustrate meaningful music-making for children, the core user base for Scratch."<ref>{{cite web |date=16 May 2019 |title=Music Making in Scratch: High Floors, Low Ceilings, and Narrow Walls? / |url=https://jitp.commons.gc.cuny.edu/music-making-in-scratch-high-floors-low-ceilings-and-narrow-walls/ |accessdate=2022-02-27 |publisher=Jitp.commons.gc.cuny.edu}}</ref>

=== Scratch Lab ===
The Scratch Lab<ref>{{Cite web |title=Scratch Lab |url=https://lab.scratch.mit.edu/ |access-date=27 September 2023 |website=lab.scratch.mit.edu}}</ref> displays experiments from the Scratch Team, intended to explore whether new features may be added to the full website in the future. Experimental features currently under development include:
* Video Sprites – Fill sprites with live video.
* Face Sensing – Make animated costumes and games that interact with your face.
* Animated Text – Bring words to life with colors, fonts, and animations.

== Community of users ==
[[File:The MADE Scratch Workshop.jpg|left|thumb|A Scratch programming workshop]]
Scratch is used in many different settings: schools, [[museum]]s, [[library|libraries]], [[Community centre|community centers]], and homes.<ref>{{cite news |url=https://www.ctvnews.ca/sci-tech/canadian-schools-starting-to-teach-computer-coding-to-kids-1.1799365 |title=Canadian schools starting to teach computer coding to kids |publisher=[[CTV.ca]] |access-date=2019-05-18 |date=2014-04-30 |first=Michael |last=Oliveira |archive-url=https://web.archive.org/web/20190518123251/https://www.ctvnews.ca/sci-tech/canadian-schools-starting-to-teach-computer-coding-to-kids-1.1799365 |archive-date=2019-05-18 |url-status=live }}</ref><ref>{{cite web |url=http://www.smm.org/ltc/scratchday |title=Scratch Day |website=Science Museum of Minnesota |access-date=18 May 2019 |url-status=dead |archive-url=https://web.archive.org/web/20130408060603/http://www.smm.org/ltc/scratchday |archive-date=2013-04-08}}</ref><ref name="ScholarWorks">{{cite journal |last1=Lamb |first1=Annette |last2=Johnson |first2=Larry |date=April 2011 |title=Scratch: Computer Programming for 21st Century Learners |url=https://scholarworks.iupui.edu/bitstream/handle/1805/8622/38-4.pdf?sequence=1 |format=PDF |journal=Teacher Librarian |volume=38 |issue=4 |pages=64–68 |access-date=18 May 2019}}</ref> Scratch is designed primarily for users aged 8–16, but it is used by all ages and has a sizeable adult user base as of 2009.<ref name=":3" /><ref name="all">{{cite journal|last1=Resnick|first1=Mitchel|last2=Maloney|first2=John|last3=Hernández|first3=Andrés|last4=Rusk|first4=Natalie|author-link4=Natalie Rusk|last5=Eastmond|first5=Evelyn|last6=Brennan|first6=Karen|last7=Millner|first7=Amon|last8=Rosenbaum|first8=Eric|last9=Silver|first9=Jay|last10=Silverman|first10=Brian|last11=Kafai|first11=Yasmin|year=2009|title=Scratch: Programming for All|url=https://web.media.mit.edu/~mres/papers/Scratch-CACM-final.pdf|journal=[[Communications of the ACM]]|volume=52|issue=11|pages=60–67|doi=10.1145/1592761.1592779|s2cid=229934947 }}</ref> This wide outreach has created many surrounding communities, both physical and digital.<ref name="statistics" /> In April 2020, the Tiobe ranking of the world's programming languages included Scratch in the top 20. According to Tiobe, there are 50 million projects written in Scratch, and every month one million new projects are added.<ref>{{cite web|url=https://devclass.com/2020/04/06/kids-programming-language-scratch-nails-top-20-in-latest-dev-rankings/|title=Kids programming language Scratch nails top 20 in latest dev rankings • DEVCLASS|last=Fay|first=Joe|date=6 April 2020|website=DEVCLASS|language=en-GB|access-date=2020-04-27}}</ref>{{-}}

=== Educational users ===
Scratch is used as the introductory language because the creation of interesting programs is relatively easy, and skills learned can be applied to other programming languages such as [[Python (programming language)|Python]] and [[Java (programming language)|Java]].

Scratch is not exclusively for creating games. With the provided visuals, programmers can create animations, text, stories, music, art, and more. There are already many programs that students can use to learn topics in math, history, and even photography. Scratch allows teachers to create conceptual and visual lessons and science lab assignments with animations that help visualize difficult concepts. Within the social sciences, instructors can create quizzes, games, and tutorials with interactive elements. Using Scratch allows young people to understand the logic of programming and how to creatively build and collaborate.<ref>{{cite web |url=https://www.avinteractive.com/features/blogs/scratch-av-25-06-2015/ |title=What is Scratch? Is it AV or IT? |date=25 June 2015 |access-date=18 May 2019 |website=AV Magazine |last=Martin |first=Neil |archive-url=https://web.archive.org/web/20190518123255/https://www.avinteractive.com/features/blogs/scratch-av-25-06-2015/ |archive-date=18 May 2019 |url-status=live }}</ref>

Scratch is taught to more than 800 schools and 70 colleges of the [[D.A.V. College Managing Committee|DAV organization]] in India and across the world.<ref>{{cite web |title=DAV CS Syllabus |url=http://davnewpanvel.com/File/5651/Syllabus%20Std-VII%202018-19.pdf |access-date=2019-05-18 |url-status=dead |archive-url=https://web.archive.org/web/20180713122300/http://davnewpanvel.com/File/5651/Syllabus%20Std-VII%202018-19.pdf |archive-date=2018-07-13}}</ref><ref>{{cite web |title=DAV Jharkhand Syllabus |url=https://drive.google.com/file/d/0BzYkgDPSlegKbFFncEdwV3czVU0/view |access-date=18 May 2019}}</ref>

In higher education, Scratch is used in the first week of Harvard University's [[CS50]] introductory computer science course.<ref>{{cite news |title=Fun, Not Fear, Is at the Heart of Scratch, a New Programming Language |url=https://www.chronicle.com/article/Fun-Not-Fear-Is-at-the-Heart/34008/ |newspaper=The Chronicle of Higher Education |date=20 July 2007 |access-date=18 May 2019 |issn=0009-5982 |first=Jeffrey R. |last=Young |archive-url=https://web.archive.org/web/20190518123249/https://www.chronicle.com/article/Fun-Not-Fear-Is-at-the-Heart/34008/ |archive-date=18 May 2019 |url-status=live }}</ref><ref>{{cite web |title=CS50 Syllabus |url=https://cdn.cs50.net/2015/x/references/syllabus/syllabus.html |access-date=2019-05-18 |archive-url=https://web.archive.org/web/20150317075307/http://cdn.cs50.net/2015/x/references/syllabus/syllabus.html |archive-date=17 March 2015 |url-status=live }}</ref>

=== Online community ===
[[File:Jumper platformer.png|thumb|[https://scratch.mit.edu/projects/103069687/ "Jumper"], an example of a game created with Scratch 2.0]]
[[File:Shadow on Scratch.png|thumb|alt=Shadow on Scratch|[https://scratch.mit.edu/projects/674693575/ "Shadow"], an example of a game created with Scratch 3.0]]
Users of Scratch are called "Scratchers". Scratchers have the capability to share their projects and receive feedback. Projects can be uploaded directly from the development environment to the Scratch website and any member of the community can view and download the full source code to study or to remix into new projects.<ref>{{cite book |title=Proceedings of the 29th International Conference on Human Factors in Computing Systems (CHI '11) |last1=Monroy-Hernandez |first1=Andres |last2=Hill |first2=Benjamin Mako |last3=Gonzalez-Rivero |first3=Jazmin |last4=Boyd |first4=Danah |publisher=ACM |year=2011 |pages=3421–30 |chapter=Computers Can't Give Credit: How Automatic Attribution Falls Short in an Online Remixing Community |doi=10.1145/1978942.1979452 |arxiv=1507.01285|s2cid=7494330 }}</ref><ref>{{cite book |title=ICWSM 2010: Proceedings of the 4th International Conference on Weblogs and Social Media, May 23–26, 2010 |last1=Hill |first1=B.M |last2=Monroy-Hernández |first2=A. |last3=Olson |first3=K.R. |publisher=AAAI Press |year=2010 |isbn=978-1-57735-445-1 |location=Washington, D.C. |chapter=Responses to remixing on a social media sharing website |oclc=844857775 |arxiv=1507.01284 |bibcode=2015arXiv150701284M}}</ref> Scratchers can also create project studios, comment, favorite, and "love" others' projects, follow other members to see their projects and activity, and share ideas. Projects range from games and animations to practical tools. Additionally, to encourage the creation and sharing amongst users, the website frequently establishes "Scratch Design Studio" challenges.<ref>{{cite web |url=https://en.scratch-wiki.info/wiki/Scratch_Design_Studio |title=Scratch Design Studio |website=wiki.scratch.mit.edu |access-date=2019-05-18 |archive-url=https://web.archive.org/web/20190518123252/https://en.scratch-wiki.info/wiki/Scratch_Design_Studio |archive-date=18 May 2019 |url-status=live }}</ref>

The MIT Scratch Team works to ensure that this community maintains a friendly and respectful environment for all people.<ref name="parents">{{cite web |url=https://scratch.mit.edu/parents/ |title=For Parents |website=scratch.mit.edu |access-date=18 May 2019 |archive-url=https://web.archive.org/web/20190404210527/https://scratch.mit.edu/parents |archive-date=4 April 2019 |url-status=live }}</ref><ref>{{cite web |url=https://scratch.mit.edu/community_guidelines |title=Scratch Community Guidelines |website=scratch.mit.edu |access-date=18 May 2019 |archive-url=https://web.archive.org/web/20190407171658/https://scratch.mit.edu/community_guidelines/ |archive-date=7 April 2019 |url-status=live }}</ref>

Educators have their own online community called ScratchEd, developed and supported by the Harvard Graduate School of Education. In this community, Scratch educators share stories, exchange resources, and ask questions.<ref>{{cite web |url=https://scratch.mit.edu/educators |title=Scratch for Educators |website=scratch.mit.edu |access-date=18 May 2010 |archive-url=https://web.archive.org/web/20081005234300/http://scratch.mit.edu/educators |archive-date=5 October 2008 |url-status=live }}</ref> 

=== Scratch Studios ===
Scratchers can upload their projects to studios where other Scratchers can upload their project for others to see and for other Scratchers to view, comment and remix their project. A studio usually consists of different projects made by Scratchers. Some Scratch studios are created by Scratchers to put all their projects into one library.

=== Scratch Wiki ===
The Scratch Wiki is a support resource for Scratch and information about its website, history, and phenomena surrounding it. Although supported by the Scratch Team (the developers of Scratch), it is primarily written by Scratch users (Scratchers) and is hosted independently of the main Scratch website.<ref name=":1">{{cite web |url=https://en.scratch-wiki.info/wiki/Scratch_Wiki |title=Scratch Wiki |website=en.scratch-wiki.info |access-date=18 May 2019 |archive-url=https://web.archive.org/web/20190512210211/https://en.scratch-wiki.info/wiki/Scratch_Wiki |archive-date=12 May 2019 |url-status=live }}</ref> There are other wikis in languages besides English available on the Scratch Wiki [https://scratch-wiki.info/ base domain].

=== Roles ===
Roles are displayed as a label under a user's username on profile pages and on forum posts. To prevent [[vandalism]], new accounts have the "New Scratcher" role, as opposed by the usual "Scratcher" role. Some restrictions are imposed onto New Scratcher accounts, including the inability to use cloud data and a minimum 30 second cooldown period between posting comments.<ref>{{cite web|title=An explanation of the 'New Scratcher' status|url=https://scratch.mit.edu/discuss/post/44802/|website=Discuss Scratch|date=June 1, 2013|author=jvvg|access-date=January 11, 2024}}</ref> After a period of time of interacting and creating projects, an account will be eligible to gain the Scratcher role.<ref>{{Cite web |url=https://mitscratch.freshdesk.com/en/support/solutions/articles/4000177710 |title=What is a Scratcher and how do I become one? |date=2021-11-04 |access-date=2024-02-10 |website=mitscratch.freshdesk.com}}</ref>

Official [[Internet forum#Moderators|moderators]] and developers of Scratch are labeled as part of the "Scratch Team" and usually have an asterisk at the end of their username.<ref>{{Cite web |title=Scratch Team - Scratch Wiki |url=https://en.scratch-wiki.info/wiki/Scratch_Team |access-date=2023-05-26 |website=en.scratch-wiki.info |language=en}}</ref> The site also has special types of accounts for Students and Educators to use Scratch in the classroom.<ref>{{Cite web |title=Student and Teacher Accounts - Scratch Wiki |url=https://en.scratch-wiki.info/wiki/Student_and_Teacher_Accounts |access-date=2023-05-26 |website=en.scratch-wiki.info |language=en}}</ref>

=== Censorship ===
In August 2020, [[GreatFire]] announced that the [[Internet censorship in China|Chinese government had blocked access]] to the Scratch website. At the time, it was estimated that more than three million people in China were using it.<ref name=":2">{{cite web |last=Liao |first=Rita |date=7 September 2020 |title=China bans Scratch, MIT's programming language for kids |url=https://techcrunch.com/2020/09/07/scratch-ban-in-china/ |access-date=27 April 2021 |website=TechCrunch |language=en-US}}</ref>{{Citation needed|date=September 2023}} The outlet cited the fact that [[Macau]], [[Hong Kong]] and [[Taiwan]] were listed as countries on the website.<ref name=":2" /><ref>{{cite web |date=8 September 2020 |title=China blocks MIT's kid-friendly programming language Scratch |url=https://developer-tech.com/news/2020/sep/08/china-blocks-mit-kid-friendly-programming-language-scratch/ |access-date=19 November 2020 |website=Developer Tech News |language=en-GB}}</ref>

== Code base ==
The [[source code]] for the project editor in all three major versions, as well as a majority of the current website, is hosted publicly on [[GitHub]] across various [[Software repository|repositories]].<ref>{{cite web |title=Scratch Source Code |url=https://en.scratch-wiki.info/wiki/Scratch_Source_Code |website=Scratch Wiki |access-date=8 April 2024}}</ref> Scratch 3.0 is [[JavaScript]]-based, 2.0 is programmed in [[ActionScript]],<ref name="flash to js" /> and the 1.x versions were based on Squeak, which itself is based on [[Smalltalk]]-80.<ref name="Squeak" />

2.0 had an experimental JavaScript-based interpreter that was being developed in parallel with the ActionScript version.<ref>{{cite web|title=We're seeking contributors to help finish our HTML5 Scratch player (now open sourced!)|url=https://scratch.mit.edu/discuss/post/174127/|website=Discuss Scratch|author=Lightnin|date=Oct 29, 2013|access-date=18 May 2019}}</ref>

In 3.0, Scratch blocks are implemented using [[Blockly]], a JavaScript library developed by Google for creating block-based [[visual programming language]]s.<ref>{{cite web |title=Blockly |url=https://developers.google.com/blockly |website=Google Developers}}</ref><ref>{{cite news |last1=Pasternak |first1=Erik |date=17 January 2019 |title=Scratch 3.0's new programming blocks, built on Blockly |url=https://developers.googleblog.com/2019/01/scratch-30s-new-programming-blocks.html |access-date=2 October 2019}}</ref>

On 13 May 2014, a year after the release of Scratch 2.0, it was announced by a developer on the Scratch Forums that 2.0 would become open source.<ref>{{cite web|title=Scratch 2.0 Offline Open Source Code!|author=speakvisually|date=May 13, 2014|url=https://scratch.mit.edu/discuss/post/322347/|website=Discuss Scratch|access-date=Jan 13, 2024}}</ref>

== Events ==
Scratch Educators can gather in person at Scratch Educator Meetups. At these gatherings, Scratch Educators learn from each other and share ideas and strategies that support computational creativity.<ref>{{cite web |url=https://www.meetup.com/pro/scratched/ |title=Scratch Educator |website=Meetup.com |access-date=18 May 2019 |archive-url=https://web.archive.org/web/20190421144408/https://www.meetup.com/pro/scratched |archive-date=21 April 2019 |url-status=live }}</ref>

An annual "Scratch Week", formerly known as "Scratch Day", is declared in May each year. Community members are encouraged to host an event on or around this day, large or small, that celebrates Scratch. These events are held worldwide, and a listing can be found on the Scratch Day website. Scratch Week is a series focusing on Scratch activities on the Scratch website.<ref>{{cite web |url=https://day.scratch.mit.edu/ |title=Scratch Week|access-date=18 May 2019 |archive-url=https://web.archive.org/web/20190407171614/https://day.scratch.mit.edu/ |archive-date=7 April 2019 |url-status=live }}</ref>

Every [[April Fools' Day]], the Scratch Team will play pranks on users and add Easter eggs, one example being that all event blocks in projects turn into cat versions of the same blocks.

== History ==
In the early 2000s, the  [[MIT Media Lab]]'s ''Lifelong Kindergarten'' group (LLK) was developing visual programming languages targeted towards children.<ref>{{cite web|title=LLK – Projects – Building-Block Programming|url=http://llk.media.mit.edu:80/projects/summaries/bbp.shtml|access-date=19 December 2021|website=llk.media.mit.edu|archive-url=https://web.archive.org/web/20010430112136/http://llk.media.mit.edu:80/projects/summaries/bbp.shtml|archive-date=30 April 2001}}</ref> In 2003, [[Mitchel Resnick]], [[Yasmin Kafai]], and [[John Maeda]] were awarded a [[National Science Foundation]] grant for the development of a new programming environment for children to express themselves with code.<ref name=":0">{{cite web|title=NSF Award Search: Award # 0325828 – ITR: A Networked, Media-Rich Programming Environment to Enhance Informal Learning and Technological Fluency at Community Technology Centers|url=https://www.nsf.gov/awardsearch/showAward?AWD_ID=0325828|access-date=15 April 2021|website=www.nsf.gov}}</ref> The LLK, led by Mitchel Resnick, in partnership with [[Yasmin Kafai]]'s team at [[University of California, Los Angeles|UCLA]] worked closely with [[The Clubhouse Network|Computer Clubhouses]] in Boston and Los Angeles to develop Scratch, grounding its design in the practices and social dynamics of these after-school youth centers.<ref name=":0" /> It started as a basic programming language, with no labeled categories and no green flag.<ref name="Dev1.0">{{cite web |url=https://en.scratch-wiki.info/wiki/Development_of_Scratch_1.0 |title=Development of Scratch 1.0 |website=en.scratch-wiki.info |access-date=18 May 2019 |archive-url=https://web.archive.org/web/20190103004838/https://en.scratch-wiki.info/wiki/Development_of_Scratch_1.0 |archive-date=3 January 2019 |url-status=live }}</ref> Similar to AgentSheets<ref name="AgentSheets">{{cite web |url=https://www.researchgate.net/publication/3651308 |title=Tactile Programming: A Unified Manipulation Paradigm Supporting Program Comprehension, Composition and Sharing|access-date=15 October 2021}}</ref> Scratch employed concepts of Tactile Programming later known as blocks-based programming. Scratch was made with the intention to teach kids to program.<ref name="Dev1.0" />

The philosophy of Scratch encourages the sharing, reuse, and combination of code, as indicated by the team slogan, "Imagine, Program, Share".<ref>{{cite web |url=https://scratch.mit.edu/ |title=Scratch – Imagine, Program, Share |website=scratch.mit.edu |access-date=18 May 2019 |archive-url=https://web.archive.org/web/20110222201702/http://scratch.mit.edu/ |archive-date=22 February 2011 |url-status=live }}</ref> Users can make their own projects, or they may choose to "[[remix]]" someone else's project. Projects created and remixed with Scratch are licensed under the [[Creative Commons Attribution-Share Alike License]].<ref>{{cite web |url=https://en.scratch-wiki.info/wiki/Creative_Commons_License |title=Creative Commons License |website=wiki.scratch.mit.edu |access-date=18 May 2019 |archive-url=https://web.archive.org/web/20190518123252/https://en.scratch-wiki.info/wiki/Creative_Commons_License |archive-date=18 May 2019 |url-status=live }}</ref> Scratch automatically gives credit to the user who created the original project and program in the top part of the project page.<ref name="ScholarWorks" />

Scratch was developed based on ongoing interaction with youth and staff at Computer Clubhouses. The use of Scratch at Computer Clubhouses served as a model for other after-school centers demonstrating how informal learning settings can support the development of technological fluency.<ref>{{cite web |title=ITR: A Networked, Media-Rich Programming Environment to Enhance Informal Learning and Technological Fluency at Community Technology Centers |url=https://www.nsf.gov/awardsearch/showAward?AWD_ID=0325828 |website=National Science Foundation |access-date=18 May 2019 |archive-url=https://web.archive.org/web/20151230194131/https://www.nsf.gov/awardsearch/showAward?AWD_ID=0325828 |archive-date=30 December 2015 |url-status=live }}</ref>

Scratch 2.0 was released on 9 May 2013.<ref name="LearnToProgram">{{cite book |title=Learn to Program with Scratch |last=Marji |first=Majed |publisher=No Starch Press |year=2014 |isbn=978-1-59327-543-3 |location=San Francisco, California |pages=xvii, 1–9, 13–15}}</ref> The update changed the look of the site and included both an online project editor and an offline editor.<ref>{{cite web |url=https://scratch.mit.edu/download |title=Scratch Desktop |website=scratch.mit.edu |access-date=2019-05-18 |archive-url=https://web.archive.org/web/20190406112722/https://scratch.mit.edu/download |archive-date=6 April 2019 |url-status=live }}</ref> Custom blocks could now be defined within projects, along with several other improvements.<ref>{{cite web |url=https://techcrunch.com/2013/05/10/kids-programming-tool-scratch-now-runs-in-the-browser/ |title=Kids' Programming Tool Scratch Now Runs in the Browser |first=John |last=Biggs |website=[[TechCrunch]] |date=10 May 2013 |access-date=18 May 2019 |archive-url=https://web.archive.org/web/20170709215339/https://techcrunch.com/2013/05/10/kids-programming-tool-scratch-now-runs-in-the-browser/ |archive-date=9 July 2017 |url-status=live }}</ref> The Scratch 2.0 Offline editor could be downloaded for Windows, Mac, and Linux directly from Scratch's website, although support for Linux was later dropped. The unofficial [[mobile phone|mobile]] version had to be downloaded from the Scratch forums.<ref>{{cite web|url=https://scratch.mit.edu/discuss/post/125955/|website=Discuss Scratch|title=Updated Scratch 2 Offline Editor (Beta) is now available!|author=Shane (grokblah), on behalf of the Scratch Team|date=Aug 29, 2013|access-date=18 May 2019}}</ref><ref>{{cite web |url=https://www.youtube.com/watch?v=qDFY4O2JU9U |title=Scratch 2.0 Preview |website=YouTube |date=2013-05-01 |publisher=MITScratchTeam |access-date=18 May 2019 |archive-url=https://web.archive.org/web/20140124200207/http://www.youtube.com/watch?v=qDFY4O2JU9U |archive-date=24 January 2014 |url-status=live }}</ref>

[[File:Scratch Website Homepage 2023.png|thumb|The Scratch website's homepage]]
Scratch 3.0 was first announced by the Scratch Team in 2016. Several public alpha versions were released between then and January 2018, after which the pre-beta "Preview" versions were released.<ref>{{cite web |url=https://en.scratch-wiki.info/wiki/Scratch_3.0 |title=Scratch 3.0 |website=en.scratch-wiki.info |access-date=18 May 2019 |archive-url=https://web.archive.org/web/20190509215315/https://en.scratch-wiki.info/wiki/Scratch_3.0 |archive-date=2019-05-09 |url-status=live }}</ref> A beta version of Scratch 3.0 was released on 1 August 2018.<ref>{{cite web |url=https://medium.com/scratchteam-blog/3-things-to-know-about-scratch-3-0-18ee2f564278 |title=3 Things To Know About Scratch 3.0 |website=Medium.com |date=31 January 2019 |access-date=18 May 2019 |archive-url=https://web.archive.org/web/20190512230529/https://medium.com/scratchteam-blog/3-things-to-know-about-scratch-3-0-18ee2f564278 |archive-date=12 May 2019 |url-status=live }}</ref> for use on most browsers; with the notable exception of [[Internet Explorer]].<ref name="3.0 FAQ">{{cite web |url=https://scratch.mit.edu/info/faq#scratch3 |title=Scratch 3.0 |website=scratch.mit.edu |access-date=18 May 2019 |archive-url=https://web.archive.org/web/20190406112722/https://scratch.mit.edu/info/faq/#scratch3 |archive-date=6 April 2019 |url-status=live }}</ref>

Scratch 3.0, the first 3.x release version, was released on 2 January 2019.<ref>{{cite web|title=Scratch 3.0 – Scratch Wiki|url=https://en.scratch-wiki.info/wiki/Scratch_3.0|access-date=27 April 2021|website=en.scratch-wiki.info}}</ref>
On 28 June 2023,<ref>{{cite web|title=Color Contrast is here!|url=https://scratch.mit.edu/discuss/post/7340551/|website=Discuss Scratch|date=June 28, 2023|author=ceebee, on behalf of the Scratch Team|access-date=September 5, 2023}}</ref> the header and links on the Scratch Website changed from blue to purple, and new optional high-contrast block colors were introduced, to make the site easier for colorblind people to read and use.<ref>{{cite web|title=Coming Soon: Color Contrast in Scratch!|url=https://scratch.mit.edu/discuss/post/7292215/|website=Discuss Scratch|date=June 5, 2023|author=ceebee, on behalf of the Scratch Team|access-date=September 5, 2023}}</ref>

In 2013, the Scratch Foundation (formerly the Code-To-Learn Foundation) was founded, and on March 11, 2019, the Scratch Team separated from the [[MIT Media Lab]] and moved to the Scratch Foundation.<ref>{{cite web|title=Supporting the Growth of Scratch - Mitchel Resnick - Medium |url=https://mres.medium.com/supporting-the-growth-of-scratch-e56dc7f84453|website=Medium|date=March 12, 2019|author=Mitchel Resnick, one of the founders of Scratch|access-date=March 5, 2024}}</ref> The MIT Media Lab continues to collaborate closely with the Scratch Foundation.

== Filetypes ==
In Scratch 1.4, an *{{Not a typo|.sb}} file was the file format used to store projects.<ref>{{cite web|url = http://en.scratch-wiki.info/wiki/.sb|title = Scratch Wiki – *.sb|date = 4 October 2015|access-date = 7 November 2015}}</ref>

An *{{Not a typo|.sb}} file is divided into four sections:
* "header", this 10-byte header contains the ASCII string "ScratchV02" in versions higher than Scratch 1.2, and "ScratchV01" in Scratch 1.2 and below
* "infoSize", encodes the length of the project's infoObjects. A 4-byte long, 32-bit, [[Endianness|big-Endian]] integer.
* "infoObjects", a dictionary-format data section. It contains: "thumbnail", a thumbnail of the project's stage; "author", the username of the project's creator; "comment", the Project Notes; "history", the save and upload log; "scratch-version", the version of Scratch used to save the file;
* "contents", an object table with the Stage as the root.<ref>{{cite web|title=Scratch File Format (1.4)/Object Table – Scratch Wiki|url=https://en.scratch-wiki.info/wiki/Scratch_File_Format/Object_Table|access-date=2022-02-19|website=en.scratch-wiki.info}}</ref> All objects in the program are stored here as references.<ref>{{cite web|title=Scratch File Format (1.4)/Object Table – Scratch Wiki|url=https://en.scratch-wiki.info/wiki/Scratch_File_Format/References|access-date=2022-02-19|website=en.scratch-wiki.info}}</ref>

Scratch 2.0 uses the *{{Not a typo|.sb2}} file format. These are essentially [[ZIP (file format)|zip files]] containing a [[JSON|.json]] file as well as the contents of the Scratch project including sounds (stored as {{Not a typo|[[WAV (file format)|.wav]]}}) and images (stored as {{Not a typo|[[PNG|.png]]}}).<ref>{{cite web |title=Scratch File Format (2.0) |url=https://en.scratch-wiki.info/wiki/Scratch_File_Format_(2.0) |website=Scratch Wiki |access-date=2 October 2019}}</ref> Each filetype, excluding the {{Not a typo|project.json}}, is stored as a number, starting at 0 and counting up with each additional file. The image file labeled "{{Not a typo|0.png}}" is always a 480x360 white image, but "{{Not a typo|0.wav}}" will still be the earliest non-deleted file.

The ScratchX experimental version of Scratch used the {{Not a typo|.sbx}} file format.<ref>{{cite web|url=https://github.com/LLK/scratchx|title=LLK/scratchx|website=GitHub|date=16 August 2022 }}</ref>

Scratch 3.0 uses the *{{Not a typo|.sb3}} format.<ref>{{cite web |title=Scratch File Format |url=https://en.scratch-wiki.info/wiki/Scratch_File_Format |website=Scratch Wiki |access-date=2 October 2019}}</ref>

== Older versions ==
Although the main Scratch website now runs only the current version (Scratch 3.0), the offline editors for Scratch 2.0 (and the earlier Scratch 1.4) are still available for download<ref>{{cite web |title=Scratch 2.0 Offline Editor |url=https://scratch.mit.edu/download/scratch2 |publisher=MIT |access-date=21 September 2019}}</ref> and can be used to create and run games locally.<ref>{{cite web |title=3 Things To Know About Scratch 3.0 |date=31 January 2019 |url=https://medium.com/scratchteam-blog/3-things-to-know-about-scratch-3-0-18ee2f564278 |publisher=The Scratch Team |access-date=21 September 2019}}</ref> It is still possible to upload projects from the Scratch 2.0 launcher, which are immediately converted into Scratch 3.0 when uploaded to the main site.<ref>{{cite web|title=Offline Editor (2.0) – Scratch Wiki|url=https://en.scratch-wiki.info/wiki/Offline_Editor_(2.0)#Uploading|access-date=2021-04-27|website=en.scratch-wiki.info}}</ref> There is also an offline version of Scratch 3.0.

=== Technology ===
The editor of Scratch 1.4 and below was written in [[Squeak]], while its online project viewer was written in [[Java (programming language)|Java]], and a player written in [[Adobe Flash]] was later added.<ref name="Squeak">{{cite web |title=Scratch |url=https://wiki.squeak.org/squeak/5833 |website=Squeak/Smalltalk |access-date=7 March 2021}}</ref><ref>{{cite web |url=https://scratcharchive.asun.co/forums/viewtopic.php?id=57148 |website=Scratch Archived Forums |access-date=7 March 2021|title=Scratch Forums / Beta Flash player }}</ref> Scratch 2.0 relied on Adobe Flash for the online version, and [[Adobe AIR]] for the offline editor. These have fallen out of favor, and Adobe dropped support for them at the end of 2020.<ref>{{cite news |last1=O'Donnell |first1=Lindsey |title=Mozilla Kills Default Support for Adobe Flash in Firefox 69 |url=https://threatpost.com/flash-default-mozilla-firefox-69/140814/ |access-date=21 September 2019 |date=14 January 2019}}</ref><ref>{{cite news |last1=Adobe Corporate Communications |title=The Future of Adobe AIR |url=https://theblog.adobe.com/the-future-of-adobe-air/ |access-date=21 September 2019 |date=30 May 2019 |archive-date=25 August 2019 |archive-url=https://web.archive.org/web/20190825060523/https://theblog.adobe.com/the-future-of-adobe-air/ |url-status=dead }}</ref>

Scratch 2.0 changed how sounds were imported, so many Scratch 1.4 sounds stopped working. (The project file was changed from *{{Not a typo|.sb}} to *{{Not a typo|.sb2}}).<ref>{{cite web |title=Reference Guide Scratch 1.4 |url=https://usm.maine.edu/stem-outreach/wp-content/uploads/sites/421/2023/10/ScratchReferenceGuide14.pdf |website=Maine EDU |publisher=Scratch.mit.edu |access-date=25 April 2025}}</ref>

=== Interface ===
[[File:Scratch Hello World.png|thumb|A script that lets the sprite say [[Hello, World!]] then stops the script in Scratch 2.0]]
In Scratch 2.0, the stage area is on the left side, with the programming blocks palette in the middle, and the coding area on the right. Extensions are in the "More Blocks" section of the palette.<ref name=all />

The web version of Scratch 2.0 introduced project autosaving.<ref name="easy steps">{{cite book |last1=McManus |first1=Sean |title=Scratch Programming in easy steps |date=2013 |publisher=Easy Steps |location=Leamington Spa |isbn=978-1-84078-612-5 }}</ref>{{rp|p=23}}

The blocks palette in Scratch 2.0 is made of discrete sections that are not scrollable from one to the next; the table below shows the different sections:
{| class="wikitable" style="text-align: left"
|+Interface sections in Scratch
|-
!scope="col" colspan="2" style="background: #efefef;" | Category
!scope="col"| Notes
|- valign="top"
| style="background:#4a6cd4;"|
|scope="row"| Motion
| Moves and changes the position of sprites
|-
| style="background:#c88340;"|
|scope="row"| Events
| Event handlers
|- valign="top"
| style="background:#8a55d7;"|
|scope="row"| Looks
| Controls the visuals of the sprite
|-
| style="background:#e1a91a;"|
|scope="row"| Control
| Conditionals and loops
|- valign="top"
| style="background:#bb42c3;"|
|scope="row"| Sound
| [[Audio files]], sequences, and music
|-
| style="background:#2ca5e2;"|
|scope="row"| Sensing
| Sprite interaction
|- valign="top"
| style="background:#0e9a6c;"|
|scope="row"| Pen
| Draw on the canvas
|-
| style="background:#5cb712;"|
|scope="row"| Operators
| Mathematical operators
|- valign="top"
| style="background:#ee7d16;"|
|scope="row"| Data
| Variables, arrays and lists
|-
| style="background:#632d99;"|
|scope="row"| More Blocks
| Functions and extensions, return value is always <code>void</code>
|}
Scratch 2.0 introduced the backpack, which can be used to transfer scripts, sprites, costumes, and sounds between projects.<ref name="easy steps"/>{{rp|pp=14–15}}

== Features ==
Scratch uses [[event-driven programming]] with multiple active objects called ''[[Sprite (computer graphics)|sprites]]''.<ref name="LearnToProgram" /> Sprites can be drawn, as [[vector graphics|vector]] or [[bitmap]] graphics, from scratch in a simple editor that is part of Scratch, or can be imported from external sources. Scratch 3.0 only supports one-dimensional [[array data structure|arrays]], known as "lists", and floating-point [[scalar (computing)|scalars]] and [[string (computer science)|strings]] are supported but with limited string manipulation ability. There is a strong contrast between the powerful multimedia functions and multi-threaded programming style and the rather limited scope of the Scratch programming language.

=== Scratch 2.0 features ===
Scratch 2.0 does not treat procedures as [[First-class object|first class structures]] and has limited [[input/output|file I/O]] options with Scratch 2.0 Extension Protocol, an experimental extension feature that allows interaction between Scratch 2.0 and other programs.<ref>{{cite web |title=Scratch Extension |publisher=MIT |url=https://en.scratch-wiki.info/wiki/Scratch_Extension |access-date=18 May 2019 |archive-url=https://web.archive.org/web/20190518123255/https://en.scratch-wiki.info/wiki/Scratch_Extension |archive-date=18 May 2019 |url-status=live }}</ref> The Extension protocol allows interfacing with hardware boards such as [[Lego Mindstorms]]<ref>{{cite web |title=EV3+Scratch Extension |work=Scratch extension GitHub |publisher=Code & Circuit |url=https://kaspesla.github.io/ev3_scratch/ |access-date=18 May 2019 |archive-url=https://web.archive.org/web/20160120204258/http://kaspesla.github.io/ev3_scratch/ |archive-date=20 January 2016 |url-status=live }}</ref> or [[Arduino]].<ref>{{cite web |title=Preliminary Scratch extension for talking to Arduino boards running Firmata |work=Scratch extension GitHub |publisher=Damellis |url=https://github.com/damellis/A4S |access-date=18 May 2019 |archive-url=https://web.archive.org/web/20180116143517/https://github.com/damellis/A4S |archive-date=16 January 2018 |url-status=live }}</ref> Scratch 2.0 also has the following features:
* Smart block switching
* Two-column category menu
* Reverse order of project controls
* Display stage on left side
* Square block inputs
* Compact editor
* Collapsing sprite properties
* Scratch 2.0 themes

=== Snap''!'' (Build Your Own Blocks) ===
A more advanced visual programming language inspired by Scratch is [[Snap! (programming language)|Snap''!'']], featuring [[first class function|first class]] procedures (their mathematical foundations are also called ''[[lambda calculus]]''), first-class lists (including lists of lists), and first-class truly object-oriented sprites with prototyping inheritance, and nestable sprites, which are not part of Scratch.<ref>{{cite web |title=Snap''!'' – Build Your Own Blocks |publisher=University of California, Berkeley |url=https://snap.berkeley.edu/ |access-date=18 May 2019 |archive-url=https://web.archive.org/web/20190516160757/https://snap.berkeley.edu/ |archive-date=16 May 2019 |url-status=live }}</ref> Snap''!'' (previously "BYOB") was developed by Jens Mönig<ref>{{cite web |url=https://scratch.mit.edu/users/Jens/ |title=Jens on Scratch |website=Scratch |first=Jens |last=Mönig |access-date=18 May 2019 |archive-url=https://web.archive.org/web/20190518123251/https://scratch.mit.edu/users/Jens/ |archive-date=18 May 2019 |url-status=live }}</ref><ref>{{cite web |url=http://www.chirp.scratchr.org/blog/?m=201105 |title=BYOB 3.1 – Prototypal Inheritance for Scratch |date=31 May 2011 |website=Chirp Blog |first=Jens |last=Mönig |access-date=18 May 2019 |url-status=dead |archive-url=https://web.archive.org/web/20131206131246/http://www.chirp.scratchr.org/blog/?m=201105 |archive-date=6 December 2013}}</ref> with documentation provided by [[Brian Harvey (lecturer)|Brian Harvey]]<ref>{{cite web |url=https://people.eecs.berkeley.edu/~bh/ |title=Brian Harvey |website=Electrical Engineering and Computer Sciences |access-date=18 May 2019 |archive-url=https://web.archive.org/web/20190403045124/https://people.eecs.berkeley.edu/~bh/ |archive-date=3 April 2019 |url-status=live }}</ref><ref>{{cite web |url=https://scratch.mit.edu/users/bharvey/ |title=bharvey |website=Scratch |access-date=18 May 2019 |archive-url=https://web.archive.org/web/20190518123251/https://scratch.mit.edu/users/bharvey/ |archive-date=18 May 2019 |url-status=live }}</ref> from [[University of California, Berkeley]] and has been used to teach "The Beauty and Joy of Computing" introductory course in CS for non-CS-major students.<ref>{{cite web |url=http://inst.eecs.berkeley.edu/~cs10/fa11/ |title=CS10 : The Beauty and Joy of Computing |website=EECS Instructional Support Group Home Page |access-date=18 May 2019 |archive-url=https://web.archive.org/web/20140123111318/http://inst.eecs.berkeley.edu/~cs10/fa11/ |archive-date=23 January 2014 |url-status=live }}</ref> Both of them were members of the Scratch Team before designing "Snap''!''".<ref>{{cite web|url=https://forum.snap.berkeley.edu/t/relationship-with-the-scratch-team/1277|title=Relationship With the Scratch Team}}</ref><ref name=all />

=== ScratchJr ===
In July 2014, [[ScratchJr]] was released for [[iPad]], and in 2016, ScratchJr for Android. Although heavily inspired by Scratch and co-led by Mitch Resnick, it is nonetheless a complete rewrite designed for younger children—targeting ages 5 through 7.<ref>{{cite web |title=About ScratchJr |url=https://www.scratchjr.org/about/info |publisher=scratchjr.org |access-date=19 September 2019}}</ref>

== Community-made modifications ==
Due to the open source nature of Scratch, numerous [[Fork (software development)|forks]] and [[browser extension]]s have been created by the community that aim to improve or modify the user experience. ScratchTools and Scratch Addons are some examples of open-sourced browser extensions that add many upgrades and new features to the Scratch website and editor.<ref>{{Cite web |title=Frequently Asked Questions |url=https://scratchaddons.com/docs/faq/ |access-date=2024-01-07 |website=Scratch Addons Docs |language=en}}</ref><ref>{{Cite journal |title=Is the Scratch Programming Environment Ideal for all? |url=https://www.scitepress.org/Papers/2023/118382/118382.pdf |journal=Proceedings of the 15th International Conference on Computer Supported Education |isbn=978-989-758-641-5}}</ref>

TurboWarp is a fork of the Scratch 3.0 editor that [[Compiler|compiles]] Scratch into [[JavaScript]] code when a project is run, resulting in projects' general preformances boosting significantly.<ref>{{Cite web |title=How TurboWarp runs Scratch projects 10-100x faster {{!}} TurboWarp Documentation |url=https://docs.turbowarp.org/how |access-date=2024-01-07 |website=docs.turbowarp.org |language=en}}</ref> In addition, there are many technical settings and the same addons that Scratch Addons provides.<ref>{{Cite web |title=TurboWarp - Run Scratch projects faster |url=https://turbowarp.org/ |access-date=2022-04-17 |website=turbowarp.org}}</ref> TurboWarp can also export projects to [[Portable Application|standalone]] [[HTML5]], [[Bundle (macOS)]] and [[.exe|EXE]] files.<ref>{{Cite web |title=TurboWarp Packager |url=https://packager.turbowarp.org/ |access-date=2024-01-07 |website=packager.turbowarp.org}}</ref>

Users can also create their own extensions for Scratch 3.0 using JavaScript.<ref>{{cite web |title=Scratch 3.0 Extensions |url=https://github.com/LLK/scratch-vm/blob/develop/docs/extensions.md |access-date=19 September 2019 |website=Github |publisher=MIT}}</ref> Although the intention for Scratch 3.0 was to allow unofficial JavaScript extensions to be developed by users, it was abandoned due to moderation risks. As a result, the official site doesn't allow JavaScript extensions to be added, but several modifications of Scratch do.

Before 2.0, a number of Scratch forks<ref>{{cite web |title=Scratch Modification |url=https://en.scratch-wiki.info/wiki/Scratch_Modification |url-status=live |archive-url=https://web.archive.org/web/20190518123253/https://en.scratch-wiki.info/wiki/Scratch_Modification |archive-date=18 May 2019 |access-date=18 May 2019 |website=Scratch Wiki |publisher=Lifelong Kindergarten Group at the MIT Media Lab}}</ref>{{Better source needed|reason=Citation is the Scratch Wiki, which is officially considered an unreliable source. Please find a non-wiki source for your info.|date=March 2024}} were created using the source code of Scratch 1.4. These programs usually only included a few extra blocks not present in Scratch.<ref>{{cite web |title=Blocks |url=https://en.scratch-wiki.info/wiki/Blocks |url-status=live |archive-url=https://web.archive.org/web/20190518123256/https://en.scratch-wiki.info/wiki/Blocks |archive-date=18 May 2019 |access-date=18 May 2019 |website=Scratch Wiki}}</ref>{{Better source needed|reason=Citation is the Scratch Wiki, which is officially considered an unreliable source. Please find a non-wiki source for your info.|date=March 2024}}

== See also ==
{{Portal|Free and open-source software|Computer programming}}
* [[Blockly]], an interface used by Scratch to make the code blocks.
* [[Snap! (programming language)]]
* [[Swift Playgrounds]]
* [[Alice (software)]]
* [[Twine (software)]]
* [[Lego Mindstorms EV3]]
* [[Kodu Game Lab]]
* [[Code.org]]
* [[Programmable Cricket]]
* [[PWCT]]
* [[Visual programming language]]
* [[Pencil Code (programming language)]]

== References ==
{{reflist}}

== External links ==
{{Commons category}}
{{Wikibooks|Scratch}}
* {{Official website}}
* [https://lab.scratch.mit.edu/ Scratch Lab]
{{Programming languages}}{{Video game engines}}
{{Authority control}}

[[Category:Dynamically typed programming languages]]
[[Category:Visual programming languages]]
[[Category:Educational programming languages]]
[[Category:Free educational software]]
[[Category:MIT Media Lab]]
[[Category:Pedagogic integrated development environments]]
[[Category:Smalltalk programming language family]]
[[Category:Video game development software]]
[[Category:Video game engines]]
[[Category:Video game IDE]]
[[Category:Software developer communities]]
[[Category:Programming languages created in 2003]]
[[Category:Computer file formats]]
[[Category:Filename extensions]]
[[Category:Creative Commons-licensed websites]]