It still translates when the network doesn't.
Most translation tools are an empty shell the moment you lose signal. JoesanTrans keeps the cache, dictionaries, translation memory and offline models on your own machine — so it works on a plane, behind a corporate firewall, or anywhere the bars run out.
macOS and Windows · Offline dictionaries in the free tier plus 1 offline model(s)
Five layers, tried in order
It works top to bottom — the earlier the hit, the faster and cheaper. Every result is labelled with the layer it came from, so you always know how you got it, and when it cost you something.
Every translation says where it came from
Each result carries the layer that produced it. That isn't decoration — it's how you tell at a glance whether this one touched the network or spent any of your quota.
“Offline-first” isn't a slogan here
Plenty of tools treat offline as a failure state: no connection, so here's an error. This one runs the other way round — local capability first, network only when local can't do the job.
When you'll be glad it works offline
At 35,000 feet
Ten hours with a document in a language you don't read. In-flight Wi-Fi is expensive and keeps dropping — the dictionaries and models are already on the laptop.
Behind the firewall
An air-gapped network can't reach outside services. The offline layers never need to, so translation carries on.
No signal
Subway, mountains, underground car park. Not a spinner that says “loading” — an actual answer.
Sensitive material
Contracts, medical records, internal documents. Text handled by the offline layers never leaves the machine.
What it actually does for you
Real lookups, not blunt machine output
Type a word and you get pronunciation, part of speech, several senses and example sentences — not one improvised rendering.
Whole documents
txt, Markdown, subtitles, Word and PDF. Code blocks, timecodes and links survive intact, and you can export a bilingual side-by-side PDF.
Translate a screenshot
Text baked into an image, an interface you can't select, an error dialog — grab it and read it.
Terminology on your terms
Import a glossary and product names and model numbers follow it exactly, or stay untranslated. No new wording every time.
Regional Chinese, properly
Not just converting characters — the vocabulary changes to what people actually say locally, and Cantonese is its own language.
Your wording sticks
Fix a translation once and it goes into memory. The same sentence reuses your version from then on.
Ready?
The free tier gives you offline dictionaries and translation memory without an account.