any-i18n

What it is

any-i18n retrofits internationalization onto websites that never had it. A Manifest V3 browser extension walks the live DOM with a TreeWalker, collects every visible text node and every translatable attribute, and turns each string into a deterministic key. Those keys can be exported, translated (by a local server, by the CLI, or by hand), imported back, and applied — replacing text in place while keeping the originals so everything can be reverted.

Nothing is patched into the website itself: no build step, no source access, no server-side changes.

Why

Plenty of pages you need to read, demo, or hand to a colleague are simply not localized — internal tools, legacy admin panels, vendor dashboards, documentation that only exists in one language. Machine page translation gives you a black box with no stable identity for a string. any-i18n gives each string a reproducible key (prefix_fnv1ahash), so a translation you fix once keeps applying on every later visit, and the whole translation set is a plain JSON file you own.

TreeWalker DOM scan

Two passes: text nodes, then translatable attributes (title, aria-label, placeholder, alt, and button-like value). Skips SCRIPT, STYLE, NOSCRIPT, IFRAME, SVG, META, LINK, HEAD, TITLE, and anything marked translate="no".

Deterministic keys

FNV-1a 32-bit hash of the normalized text, prefixed with its first three words — the same sentence always produces the same key, on any page and any run.

Reversible in-place rewrite

Originals are kept in a Map, so one click restores the page exactly. Attribute values are restored too.

SPA aware

A MutationObserver (50 ms debounce) translates content added later, and pushState, replaceState, popstate, and hashchange are intercepted to handle client-side navigation.

Local translation server

A FastAPI service batches keys to a configurable LLM backend, streams results back over SSE, and caches every translation in SQLite so repeat visits cost nothing.

Node CLI

translate, validate, and bundle for working with exported key files and shipping translations inside the extension.

The three components

Component	Location	Role
Browser extension	extension/	Manifest V3, plain JS, no bundler. Scans, applies, and reverts translations; popup and in-page toolbar UI.
Translation server	server/	FastAPI + SQLite. POST /api/translate and a streaming POST /api/translate/stream, plus health, stats, and language endpoints.
CLI	cli/	Node 22.12+ ESM tool built on commander for translating, validating, and bundling translation JSON.

How a page gets translated

1. Scan — the content script walks document.body and collects text nodes and attributes.
2. Key generation — each normalized string becomes firstthreewords_fnv1ahash.
3. Translate — the extension posts unknown keys to the local server, or you export the keys and translate them with the CLI or by hand.
4. Apply — matching keys are written back into the DOM; originals are remembered.
5. Stay applied — the MutationObserver translates new nodes as the page changes.
6. Revert — one action restores every original text node and attribute value.

Continue with Installation, then Configuration.