Which translation engines are free with no setup?

Google Translate, MyMemory, and LibreTranslate work out of the box with no account or API key. Google is the default; MyMemory is a free fallback; LibreTranslate is open-source and self-hostable if you want to run your own instance.

Do I need an API key for DeepL, DeepSeek, or OpenAI?

Yes, all three are bring-your-own-key. DeepL's free API tier needs sign-up. DeepSeek and OpenAI (GPT-4o-mini) are pay-as-you-go — you pay the provider directly, not OpenImmersive.

Is my API key ever sent to OpenImmersive's servers?

No. Bring-your-own-key engines are called directly from your browser using your key. OpenImmersive has no backend to route the request through or to store the key on.

Which engine gives the best translation quality?

For general text, DeepL is typically the highest quality of the free-tier options. For nuanced or context-heavy text, an AI engine (DeepSeek or OpenAI GPT-4o-mini) can outperform traditional machine translation, at the cost of paying per request.

Can I self-host my translation engine instead of using a third party?

Yes — LibreTranslate is open-source and self-hostable, so you can run your own instance and point the extension at it instead of relying on a public API.

Free Translation Engines Compared: Google, MyMemory, LibreTranslate, DeepL, DeepSeek, OpenAI

Every translation extension has to send your text somewhere to get it translated — the question is which engine, at what cost, and under whose terms. OpenImmersive doesn’t pick one engine for you; it lets you choose per-translation, and free engines work with zero setup.

Key facts

Engine	Free?	Needs a key?	Note
Google Translate	Yes	No	Default, works out of the box
MyMemory	Yes	No	Free fallback
LibreTranslate	Yes	No	Open-source, self-hostable
DeepL Free API	Sign-up required	Yes	Highest quality of the free-tier options
DeepSeek	Pay-as-you-go	Yes	Very low-cost AI translation
OpenAI GPT-4o-mini	Pay-as-you-go	Yes	High-quality AI translation

Last updated: 2026-07-04

Free, zero-setup engines

Google Translate is the default — it needs no account and no key, and covers the vast majority of language pairs well. MyMemory is a free fallback when you want a second opinion or hit a rate limit. LibreTranslate is the odd one out in a good way: it’s fully open-source, and if you don’t want to depend on a third-party API at all, you can self-host it and point the extension at your own instance.

Bring-your-own-key engines

Once you want higher quality or AI-native translation, you bring your own API key: DeepL (sign up for their free API tier), DeepSeek (pay-as-you-go, notably cheap for an AI engine), and OpenAI’s GPT-4o-mini (pay-as-you-go, high-quality AI translation). In every case, the key lives only in your browser’s local storage — OpenImmersive has no server to route the request through, so the request goes straight from your browser to whichever engine you picked, using your key.

Picking one

Just want it to work: Google Translate, no setup.
Hit a rate limit or want a second source: MyMemory.
Want zero third-party dependency: self-host LibreTranslate.
Want the best traditional MT quality: DeepL.
Want AI-level nuance and are fine paying per request: DeepSeek (cheaper) or GPT-4o-mini (also strong, similarly priced).

Key takeaways

You’re never locked into one engine — free options need nothing, premium ones need your own key.
No key is ever seen by OpenImmersive — every request goes browser-to-engine directly.
If you want a fully open-source, self-hostable path end to end, LibreTranslate is the one to look at.