★ 399
September 2026
Apache-2.0
Translation & language
What we checked ourselves
Not copied from the project's own blurb. These are things we opened and verified, with the date.
- 23 Aug 2026We checked that the link to the project still resolves.
- 14 Aug 2026We read the licence text itself (LICENSE). No unusual restrictions were stated.
- 2 Sept 2026We read the project's own documentation and found no sign that development has stopped.
Where this sits among the 26 tools we list in Translation & language
- Works without using a terminal20 of 26
- No API key required20 of 26
- Keeps your data on your own machine12 of 26
- Commercial use confirmed as allowed22 of 26
Only 7 of the 26 meet all of the conditions above.
Counted from our own checks: every tool we list is examined against the same criteria.
What it does
Look up words while you read — novels, visual novels, anything with selectable text — with verb deconjugation so inflected forms resolve to their dictionary entry, pitch-accent display when you add a suitable dictionary, and custom word and name lists of your own. Supports a wide range of dictionary formats and lets you tune size, colour, opacity and hotkeys for almost everything. Windows, .NET Desktop Runtime 10 or later; dictionaries are sourced separately. Apache-2.0.
Summary based on the project's own description. The Japanese page has a fuller beginner guide: setup difficulty, what to prepare, and a step-by-step start.
Screenshots & visuals
Before you start
- Setup difficultySome setup needed
- Command lineNot required
- API keyNot required
- Sends data onlineNo
Judged automatically from the project's own metadata. Always confirm on the official page.
JL FAQ
- Is JL free?
- Yes. It runs on your own machine, so there is no usage-based cost either.
- Do I need to install anything or write code to use JL?
- You install it like a normal desktop app. No command line involved.
- Does JL work on a phone?
- No. It needs a computer.
- Does JL support Japanese?
- Yes, Japanese is supported.
- Can I use JL commercially?
- The licence is Apache-2.0, which permits commercial use. Conditions such as keeping the copyright notice still apply, so read the licence text before shipping it inside something.
How it compares
The conditions that decide whether you can actually use it, side by side.
| Tool | Command line | API key | Sends data out | Phone | Commercial use |
|---|---|---|---|---|---|
| JL (this page) | Not needed | Not needed | No | No | Yes |
| YomiNinja | Not needed | Not needed | No | No | Yes |
| RTranslator | Not needed | Not needed | No | Yes | Yes |
| Translate Web Pages (TWP) | Not needed | Not needed | Yes | No | Yes |
"Sends data out" means your input is uploaded to someone's server. Pick "No" when the material cannot leave your organisation.