Pop-up dictionary browser extension for language learning. Successor to Yomichan.
2,821
stars
5,251
commits
JavaScript
primary language
Sep 8, 2026
updated
:wave: Yomitan is the successor to Yomichan (migration guide) which was sunset by its owner on Feb 26, 2023. We have made a number of foundational changes to ensure the project stays alive, works on latest browser versions, and is easy to contribute to.
📢 New contributors welcome!
📢 Interested in adding a new language to Yomitan? See here for thorough documentation!
Yomitan turns your web browser into a tool for building language literacy by helping you read texts that would otherwise be too difficult to tackle in a variety of supported languages.
Yomitan provides powerful features not available in other browser-based dictionaries:
Please visit the Yomitan Wiki for the most up-to-date usage documentation.
Yomitan comes in two flavors: stable and testing. New changes are initially introduced into the testing version, and after some time spent ensuring that they are relatively bug free, they will be promoted to the stable version. If you are technically savvy and don't mind submitting issues on GitHub, try the testing version; otherwise, the stable version will be your best bet. Check contributing for more information on how to help.
Google Chrome
Mozilla Firefox
Microsoft Edge
※ Unlike Chrome, Firefox does not allow extensions meant for testing to be hosted in the marketplace. You will have to download the desired version and side-load it yourself. You only need to do this once, and you will get updates automatically.
🚀 Dip your toes into contributing by looking at issues with the label good first issue.
Since this is a distributed effort, we highly welcome new contributors! Feel free to browse the issue tracker, and read our contributing guidelines.
Here are some ways anyone can help:
area/bug older than 2 months need help reproducing. If anything interests you, please try to reproduce it and report your results. We can't easily tell if these issues are one-off, have since been resolved, or are no longer relevant.The current active maintainers of Yomitan spend a lot of their time debugging and triaging issues. When someone files a bug report, we need to assess the frequency and severity of the bug. It is extremely helpful if we get multiple reports of people who experience a bug or people who can contribute additional detail to an existing bug report.
If you're looking to code, please let us know what you plan on working on before submitting a Pull Request. This gives the core maintainers an opportunity to provide feedback early on before you dive too deep. You can do this by opening a GitHub Issue with the proposal.
Some contributions we always appreciate:
Information on how to setup and build the codebase can be found here.
If you want to add or improve support for a language, read the documentation on language features.
Feel free to join us on the Yomitan Discord.
Run npm ci to set up the environment.
Run npm run license-report:html to generate any missing or changed license information.
Run npm run build for a plain testing build or npm run-script build -- --all --version {version} for a release build (replacing {version} with a version number).
The builds for each browser and release branch can be found in the builds directory.
For more information, see Contributing.
Yomitan uses several third-party libraries to function.
| Name | License type | Link |
|---|---|---|
| @resvg/resvg-wasm | MPL-2.0 | git+ssh://git@github.com/yisibl/resvg-js.git |
| @zip.js/zip.js | BSD-3-Clause | git+https://github.com/gildas-lormeau/zip.js.git |
| dexie | Apache-2.0 | git+https://github.com/dexie/Dexie.js.git |
| dexie-export-import | Apache-2.0 | git+https://github.com/dexie/Dexie.js.git |
| hangul-js | MIT | git://github.com/e-/Hangul.js.git |
| kanji-processor | n/a | https://registry.npmjs.org/kanji-processor/-/kanji-processor-1.0.2.tgz |
| parse5 | MIT | git://github.com/inikulin/parse5.git |
| yomitan-handlebars | MIT | n/a |
| linkedom | ISC | git+https://github.com/WebReflection/linkedom.git |
fallback-bloop.mp3 is provided by UNIVERSFIELD and licensed under the Pixabay Content License.
(top 30 of 130)
JavaScript
84.7%
HTML
8.7%
CSS
4.9%
Handlebars
1.7%
Pop-up dictionary browser extension for language learning. Successor to Yomichan.
2,821
stars
5,251
commits
JavaScript
primary language
Sep 8, 2026
updated
:wave: Yomitan is the successor to Yomichan (migration guide) which was sunset by its owner on Feb 26, 2023. We have made a number of foundational changes to ensure the project stays alive, works on latest browser versions, and is easy to contribute to.
📢 New contributors welcome!
📢 Interested in adding a new language to Yomitan? See here for thorough documentation!
Yomitan turns your web browser into a tool for building language literacy by helping you read texts that would otherwise be too difficult to tackle in a variety of supported languages.
Yomitan provides powerful features not available in other browser-based dictionaries:
Please visit the Yomitan Wiki for the most up-to-date usage documentation.
Yomitan comes in two flavors: stable and testing. New changes are initially introduced into the testing version, and after some time spent ensuring that they are relatively bug free, they will be promoted to the stable version. If you are technically savvy and don't mind submitting issues on GitHub, try the testing version; otherwise, the stable version will be your best bet. Check contributing for more information on how to help.
Google Chrome
Mozilla Firefox
Microsoft Edge
※ Unlike Chrome, Firefox does not allow extensions meant for testing to be hosted in the marketplace. You will have to download the desired version and side-load it yourself. You only need to do this once, and you will get updates automatically.
🚀 Dip your toes into contributing by looking at issues with the label good first issue.
Since this is a distributed effort, we highly welcome new contributors! Feel free to browse the issue tracker, and read our contributing guidelines.
Here are some ways anyone can help:
area/bug older than 2 months need help reproducing. If anything interests you, please try to reproduce it and report your results. We can't easily tell if these issues are one-off, have since been resolved, or are no longer relevant.The current active maintainers of Yomitan spend a lot of their time debugging and triaging issues. When someone files a bug report, we need to assess the frequency and severity of the bug. It is extremely helpful if we get multiple reports of people who experience a bug or people who can contribute additional detail to an existing bug report.
If you're looking to code, please let us know what you plan on working on before submitting a Pull Request. This gives the core maintainers an opportunity to provide feedback early on before you dive too deep. You can do this by opening a GitHub Issue with the proposal.
Some contributions we always appreciate:
Information on how to setup and build the codebase can be found here.
If you want to add or improve support for a language, read the documentation on language features.
Feel free to join us on the Yomitan Discord.
Run npm ci to set up the environment.
Run npm run license-report:html to generate any missing or changed license information.
Run npm run build for a plain testing build or npm run-script build -- --all --version {version} for a release build (replacing {version} with a version number).
The builds for each browser and release branch can be found in the builds directory.
For more information, see Contributing.
Yomitan uses several third-party libraries to function.
| Name | License type | Link |
|---|---|---|
| @resvg/resvg-wasm | MPL-2.0 | git+ssh://git@github.com/yisibl/resvg-js.git |
| @zip.js/zip.js | BSD-3-Clause | git+https://github.com/gildas-lormeau/zip.js.git |
| dexie | Apache-2.0 | git+https://github.com/dexie/Dexie.js.git |
| dexie-export-import | Apache-2.0 | git+https://github.com/dexie/Dexie.js.git |
| hangul-js | MIT | git://github.com/e-/Hangul.js.git |
| kanji-processor | n/a | https://registry.npmjs.org/kanji-processor/-/kanji-processor-1.0.2.tgz |
| parse5 | MIT | git://github.com/inikulin/parse5.git |
| yomitan-handlebars | MIT | n/a |
| linkedom | ISC | git+https://github.com/WebReflection/linkedom.git |
fallback-bloop.mp3 is provided by UNIVERSFIELD and licensed under the Pixabay Content License.
(top 30 of 130)
JavaScript
84.7%
HTML
8.7%
CSS
4.9%
Handlebars
1.7%