Local-first Twitch bot

Your chat speaks three languages.
Now you can follow all of them.

snowy-twitch-bot translates your Twitch chat, reads it aloud in the right voice, and answers language questions — running entirely on your own machine.

Runs on your PC Free by default No chat data leaves unless you choose an online engine

Translation that understands how chat is actually written

Real chat is short, code-switched, and full of noise. Most translation bots quietly drop exactly those messages. This one is built around them.

what does 一期一会 mean?: Recognised as an English question quoting a Japanese term — translated outward to your audience, not back into English. Four kanji don't get to outvote an English sentence.
この clip 最高: Stays Japanese. A borrowed English word doesn't flip the direction.
hello: Five letters is enough. Short greetings are the most common message in chat, and the one most bots fail on.
gg wp: Recognised as shorthand and skipped — no API call, no nonsense translation.

Never silent

Nothing disappears

When local detection can't name a language, the translation engine's own detection decides — and can correct the route afterwards. A message is never dropped for lacking a label.

Cost

Cached and layered

Repeat phrases are answered from a local cache. Engines are tried in order with automatic failover, so one provider being down doesn't stop the stream.

Control

Rules, not guesswork

Per-language routing rules, ignore lists for bots and noise, and a ja:-style prefix any viewer can use to force a target language.

Chat, read aloud — in the right voice for each language

A single message is often bilingual. Reading it with one voice mangles half of it, so each run is voiced in its own language.

ありがとう thanks a lot: Split into a Japanese run and an English run — each spoken by its own configured voice.

✓Every viewer keeps their own voice. Assigned from their name, so the same person sounds the same tomorrow, and on another machine. You start recognising regulars by ear.
✓Names are said, not spelled. A login like night_owl is read as words, and the announcement is spoken in the language being read — not always in English.
✓A pronunciation dictionary fixes names and in-jokes the engine gets wrong. It changes only what is spoken, never what your viewers see.
✓Built for a busy chat. Your own commands never queue behind backlog, repeated spam is spoken once, long messages are trimmed at a word boundary, and stale messages are dropped rather than read minutes late.
✓Stop instantly. Skip the current line, or clear everything waiting, without stopping the bot.

An AI language helper your viewers can use

Four commands, answered briefly enough to read on a stream.

Command	What it does	Example answer
`^a`	Explain a word or phrase	“Ichigo ichie means that every encounter is unique and will never happen again.”
`^g`	Check grammar	“I have a pen. The subject ‘I’ requires ‘have’, not ‘has’.”
`^n`	Explain nuance and register	“Yabai is versatile casual slang — anything from terrible to amazing, depending on tone.”
`^ai`	Ask a general question	Short, direct, and says so when it doesn't know.

Cost control

Built for strangers

Every AI call is triggered by a viewer and costs money. A per-viewer cooldown, a channel-wide ceiling, and a concurrency cap are part of the design — not options you have to remember to switch on.

Fairness

Outages are on us

If a request never reaches a provider, the viewer gets their cooldown back instead of being charged for a failure that wasn't theirs.

Choice

Bring your own key

Works with a free-tier Google AI Studio key, or any OpenAI-compatible provider — including a model running on your own machine.

Made to sit beside a live stream

Workspace

A focused chat window

A second window with just chat and translations. Adjustable reading size and background transparency, optional always-on-top, and a hideable title bar.

Setup

Three minutes, not three hours

Authorize Twitch once, pick two languages, and choose whether translations stay private or post to chat. Everything else has a sensible default.

Depth

Advanced when you want it

Engine order and health, routing rules, filters, a side-effect-free translation lab, and profile export/import — all behind one toggle.

Languages

Trilingual interface

The app and its setup guide are written in English, Japanese, and Traditional Chinese, sharing one runtime.

Personality

Not a machine printout

Configurable kaomoji, local mood detection, and translation style presets, so the bot sounds like part of your channel.

Privacy

Your machine, your keys

Credentials are stored encrypted by the operating system, never in plain configuration files. Local voice engines mean chat audio never leaves your PC.

Free by default

The default setup costs nothing. Paid providers are upgrades, never requirements.

Job	Free option	Optional upgrade
Translation	Google AI Studio free tier, or a free proxy	Google Cloud Translation
Voice	VOICEVOX or AivisSpeech — local, no key	Cloud voices
AI helper	Google AI Studio free tier	Any OpenAI-compatible provider
Language detection	Runs locally, no API call	—

What's here, and what's next

An honest list. Shipped means shipped and tested.

✓Chat translation with mixed-language routing, caching, and failover
✓Text-to-speech with per-language voices, per-viewer voices, and a pronunciation dictionary
✓AI explain / grammar / nuance / ask, with built-in spending limits
✓Streamer chat window, trilingual dashboard, profile transfer
◦Audio output-device selection, for routing voice into OBS
◦Dictionary lookups across multiple Japanese and English sources
◦Viewer profiles, greetings, and stream overlays

What you need

WindowsDesktop app with a system-tray presence.
A Twitch accountAuthorize once. A separate bot account is supported, and recommended if you post translations publicly.
Optional: a voice engineVOICEVOX or AivisSpeech, both free, if you want chat read aloud.
Optional: an API keyA free-tier key improves translation quality and enables the AI commands.