polygo

Lokalise for one person. A 4 MB CLI binary that translates your app's strings with a local model, tracks what changed in a lockfile, and refuses to write a translation with a broken placeholder or a missing plural form.

For solo developers and small teams shipping an iOS, Android, Flutter, web or .NET app in a few languages. Lokalise starts at $149/month and keeps your strings on its servers. polygo runs in your repo and writes into the files you already have, so the diff is just the new strings.

curl -fsSL https://raw.githubusercontent.com/Na5co/polygo/main/install.sh | sh

_{Or brew install na5co/tap/polygo · cargo binstall polygo · cargo install polygo · Windows zip. Local models run through Ollama (brew install ollama); no Ollama? polygo use openai/gpt-4o-mini --api-key ... works the same way.}

Thirty seconds

cd your-app
polygo init          # finds your string files, writes polygo.toml
polygo use gemma4    # picks a model and pulls it (or openai/..., anthropic/... with a key)
polygo doctor        # is everything in place? says what to fix if not
polygo translate     # translates new and changed strings into every target locale
polygo check         # placeholders, plurals, lengths; exit 1 on errors
git diff             # look it over, commit

init recognises .xcstrings catalogs, Android values-* folders, Flutter l10n.yaml and ARB files, i18next locales/, gettext .po trees and .NET .resx/.resw. polygo add fr ja adds languages later.

Web app with no string files yet

polygo extract --dry-run   # lists every piece of UI text it found, with file:line
polygo extract --rewrite   # writes locales/en.json, replaces the strings in the code with t("key"), generates src/i18n.ts
polygo init && polygo add de fr && polygo translate

extract reads the markup in JSX, HTML inside template literals, and .html/.vue/.svelte files: text between tags plus placeholder, title, alt and aria-label attributes. It skips <script>, <style>, <svg>, <code>, tests and node_modules. ${expr} and {expr} become {{0}} placeholders and are passed as arguments: <p>Signed in as ${email}.</p> becomes <p>${t("Signed in as {{0}}.", { 0: email })}</p>.

--rewrite edits .ts/.tsx/.js/.jsx files in place, adds the import, and generates a 20-line i18n.ts with t, setLocale and addCatalog (no library needed; keys are the English text, so English works with nothing loaded). Review it with git diff. Sentences split by inline markup (writes a <code>.form</code> file) are listed as fragments and left alone, because translating the pieces separately gives bad results. On a 160-file server-rendered app it rewrote 387 strings in 20 files with no new TypeScript errors.

Keep brand names and whole pages out of it with flags or polygo.toml:

[extract]
ignore = ["Leafslip", "API key"]          # strings containing these are skipped
ignore_paths = ["src/admin*", "legacy/**"]

iOS, Android, Flutter and gettext already have their own extractors, so extract is for the web.

What it catches

This is polygo check on the DuckDuckGo macOS browser's shipped string catalog, unmodified:

$ polygo check
error   Localizable.xcstrings  open.in  [fr]  placeholders: missing %1$@
error   Localizable.xcstrings  open.in  [it]  placeholders: missing %1$@
error   Localizable.xcstrings  permission.popup.title  [it]  placeholders: missing %#@…@
error   Localizable.xcstrings  tooltip.clearHistory  [it]  placeholders: missing %1$@
error   Localizable.xcstrings  preferences.about.more-at  [nl]  placeholders: missing %1$@
error   Localizable.xcstrings  fire.dialog.history.count  [pl]  placeholders: missing %#@…@
error   Localizable.xcstrings  pm.card.expires.format  [pl]  placeholders: missing %1$@
…
12 error(s), 380 warning(s)

Ouvrir dans % @ (a space inside the placeholder), a dropped %d, mangled %#@var@ variables. Across DuckDuckGo and Ice Cubes: 32 placeholder bugs and 44 missing Slavic plural forms, all in production, plus a Ukrainian string that reads "ключа DeepL API key". Details in tests/corpus/xcstrings/KNOWN_BUGS.md.

Formats

Every writer round-trips byte for byte: parse then serialize gives back the original file. Tested on 35 real files from DuckDuckGo, Ice Cubes, Grafana, Django, NewPipe, Penpot and others, so a translation never hides a real change under a reformatting diff. Per-format notes are in docs/.

Why not paste the file into a chat window

Compared with

polygo is MIT-licensed and open source. There is no hosted tier, no account and no telemetry.

Which model

polygo models lists the options with sizes and notes. The workflow is the same whichever you pick.

check catches structural mistakes, not a wrong word, so step up from the default for anything a customer will read.

polygo use gemma4                               # pulls through Ollama with a progress bar, writes polygo.toml
polygo use qwen3:14b --global                   # also the default for future `polygo init`
polygo use openai/gpt-4o-mini --api-key sk-...  # key stored in ~/.config/polygo/credentials.toml (0600)
polygo use anthropic/claude-sonnet-5            # or export ANTHROPIC_API_KEY
polygo use openai/llama-3.3-70b --base-url https://api.groq.com/openai/v1   # any OpenAI-compatible server

Privacy

• No telemetry, no analytics, no update checks. The only network request polygo makes is the translation call to the provider in your polygo.toml. With the default Ollama provider that is 127.0.0.1:11434. The one opt-in exception: set PHOENIX_COLLECTOR_ENDPOINT and prompts and replies are also exported as traces to that address, for your own Phoenix instance.
• check, status, review and init never touch the network. translate --dry-run lists what would be sent and sends nothing. The test suite makes no network calls.
• polygo review binds to 127.0.0.1 only and rejects requests whose Host header is not localhost.
• Nothing is written outside your repo (polygo.toml, polygo.lock, your string files) except ~/.config/polygo/ when you ask for it with --global or --api-key.
• One static binary, about 4 MB, no runtime dependencies. Built on GitHub Actions; every release ships a SHA256SUMS.
• API keys come from POLYGO_API_KEY, OPENAI_API_KEY / ANTHROPIC_API_KEY, or ~/.config/polygo/credentials.toml (mode 0600; the environment wins). They are only sent to the base_url you configured.

cat > offline.sb <<'SB'
(version 1) (allow default) (deny network*) (allow network* (remote ip "localhost:11434"))
SB
sandbox-exec -f offline.sb polygo translate
# translated 2 string(s) in 1 batch(es) with ollama (qwen3:8b)

Configuration

polygo init and polygo use write this for you; here is everything it can hold.

source_locale = "en"
target_locales = ["de", "fr", "ja"]
batch_size = 20        # strings per model call
jobs = 1               # parallel model calls
context = true         # attach code usage and similar translations to prompts
memory = true          # use the cross-project translation memory
glossary = "glossary.toml"

[[files]]
format = "android"
path = "app/src/main/res/values/strings.xml"
locale_path = "app/src/main/res/values-{android_locale}/strings.xml"

[provider]
kind = "ollama"                          # or "openai", "anthropic"
model = "qwen3:8b"
timeout_secs = 300
# base_url = "https://api.openai.com/v1"  # any OpenAI-compatible server: llama.cpp, vLLM, LM Studio, OpenRouter

glossary.toml pins brand names and required translations:

do_not_translate = ["Polygo", "GitHub"]

[terms.de]
"Sign in" = "Anmelden"

Commands

FAQ

Does it work offline? Yes. The default provider is Ollama on localhost; check, status, review and init never use the network at all. See Privacy for how to prove it with sandbox-exec.

Will it overwrite translations I edited by hand? No. The lockfile marks them edited; translate and audit --fix skip them. The one exception is check --fix, which re-translates a hand-edited string only when it has a structural error such as a missing placeholder.

Can I use OpenAI, Anthropic, Groq, OpenRouter or my own llama.cpp / vLLM / LM Studio server? Yes: polygo use openai/<model> --base-url <url> --api-key <key>, or polygo use anthropic/<model>. Any OpenAI-compatible endpoint works.

Does it send my strings anywhere? Only to the provider in your polygo.toml, and only the strings that need translating (translate --dry-run shows exactly which). With Ollama that is 127.0.0.1.

Is it free? MIT, no account, no tier. Ollama models cost nothing; API models cost whatever your provider charges.

The model is bad at my language. Switch to gemma4 or an API model (polygo use), run polygo audit to have a second model grade the output, and approve or reject the flagged ones in polygo review.

My app has no string files yet. Web: polygo extract builds locales/en.json from your markup. iOS, Android, Flutter and gettext: use the platform's own extractor, then polygo init.

Does it run in CI? polygo check --json --strict fails the build on broken placeholders; the GitHub Action translates on push and opens a PR.

Development

cargo test                  # offline, about 10 s
cargo test --features live  # also hits a local Ollama
scripts/killtest.sh tests/corpus/xcstrings/loop.xcstrings de   # blind A/B judged by a second model
scripts/demo.sh             # re-record docs/demo.gif (vhs + ffmpeg)

MIT