Ship multilingual apps. Translate only what changed.
PolyCLI runs in your build pipeline, detects the delta in your JSON files, and uses AI to translate only new or modified strings. Local, fast, and SEO-perfect.
Three commands. Fully automated.
Init
Creates buildtranslator.json with your source language, target languages, and file paths.
polycli initEdit
Modify strings in your source JSON (e.g. en.json). PolyCLI tracks the last translated state via a local lockfile.
Run
Only new or changed strings are sent to the AI. Translated files are written to disk.
polycli run50+ languages. One command.
Any language the AI supports, PolyCLI translates.
Everything a serious i18n workflow needs.
Delta Algorithm
Only new or modified strings are sent to the API. Unchanged content costs zero credits.
Variable Preservation
Variables, ICU plurals, and HTML tags are tokenised before translation and restored after.
JSON + Markdown
Handles both i18n JSON files and .md documentation with separate delta tracking per file type.
Structured Outputs
Strict JSON schema enforced — keys are never added, removed, or renamed by the AI.
CI-Friendly
Plain Node.js binary. No daemon, no watch mode. Drop it into your build step or schedule.
Credit-Based Billing
Buy credits once, use them forever. Billed only after variable extraction. No subscription.
Why PolyCLI?
See how it stacks up against the alternatives.
| Feature | PolyCLI | Manual | Cloud SaaS |
|---|---|---|---|
| Cost per run | Pay per word (delta only) | High (agency / freelancer) | Subscription + per-word |
| Runtime overhead | 0 ms | 0 ms | Varies |
| Delta detection | |||
| Variable preservation | Varies | Varies | |
| CI/CD native | Sometimes | ||
| Setup time | < 5 min | Days | Hours |
Works anywhere in your pipeline.
Drop it into any CI environment — no daemon, no config server.
Simple, honest pricing.
Pay per word translated. No subscription. Credits never expire.