PolyCLI
⚡ i18n automation + Document Translation — AI-powered

Ship multilingual apps. Translate only what changed.

PolyCLI runs in your build pipeline to translate JSON, Markdown, and ARB files — detecting only the changed strings. Also translates .docx and .pdf documents directly from the dashboard, privacy-first.

no install needed
npx @polycli/cli run
$ npx @polycli/cli run --key bt_live_••••••
✓ Loading config...
✓ 3 new keys detected
⟳ Translating to es...[]
⟳ Translating to fr...[]
⟳ Translating to de, ja...[]
✓ Done in 1.2s — 47 credits used
🇬🇧 EN🇪🇸 ES🇫🇷 FR🇩🇪 DE🇮🇹 IT🇯🇵 JA🇨🇳 ZH🇰🇷 KO🇧🇷 PT🇸🇦 AR🇷🇺 RU🇮🇳 HI🇺🇦 UK🇹🇭 TH🇻🇳 VI🇮🇩 ID🇭🇺 HU🏴󠁥󠁳󠁣󠁴󠁿 CA🇳🇴 NO🇿🇦 AF🇧🇩 BN🇵🇭 FIL🇲🇦 ARY
0 ms
Runtime overhead
~90%
Cost saved vs full retranslation
0
Languages supported

Three commands. Fully automated.

01

Init

Creates buildtranslator.json with your source language, target languages, and file paths.

polycli init
02

Edit

Modify strings in your source JSON (e.g. en.json). PolyCLI tracks the last translated state via a local lockfile.

03

Run

Only new or changed strings are sent to the AI. Translated files are written to disk.

polycli run

50+ languages. One command.

Any language the AI supports, PolyCLI translates.

🇬🇧English🇪🇸Spanish🇫🇷French🇩🇪German🇮🇹Italian🇯🇵Japanese🇨🇳Chinese (Simplified)🇹🇼Chinese (Traditional)🇰🇷Korean🇧🇷Portuguese (BR)🇵🇹Portuguese (PT)🇸🇦Arabic🇷🇺Russian🇳🇱Dutch🇵🇱Polish🇹🇷Turkish🇸🇪Swedish🇳🇴Norwegian🇩🇰Danish🇫🇮Finnish🇨🇿Czech🇭🇺Hungarian🇷🇴Romanian🇬🇷Greek🇮🇱Hebrew🇹🇭Thai🇻🇳Vietnamese🇮🇩Indonesian🇮🇳Hindi🇺🇦Ukrainian🇧🇩Bengali🇲🇾Malay🇵🇭Filipino🇭🇷Croatian🇸🇰Slovak🇧🇬Bulgarian🇷🇸Serbian🇱🇹Lithuanian🇱🇻Latvian🇪🇪Estonian🇸🇮Slovenian🇦🇱Albanian🇲🇰Macedonian🇿🇦Afrikaans🇰🇪Swahili🇮🇷Persian🇵🇰Urdu🇰🇿Kazakh🏴󠁥󠁳󠁣󠁴󠁿Catalan🇮🇳Tamil🇬🇧English🇪🇸Spanish🇫🇷French🇩🇪German🇮🇹Italian🇯🇵Japanese🇨🇳Chinese (Simplified)🇹🇼Chinese (Traditional)🇰🇷Korean🇧🇷Portuguese (BR)🇵🇹Portuguese (PT)🇸🇦Arabic🇷🇺Russian🇳🇱Dutch🇵🇱Polish🇹🇷Turkish🇸🇪Swedish🇳🇴Norwegian🇩🇰Danish🇫🇮Finnish🇨🇿Czech🇭🇺Hungarian🇷🇴Romanian🇬🇷Greek🇮🇱Hebrew🇹🇭Thai🇻🇳Vietnamese🇮🇩Indonesian🇮🇳Hindi🇺🇦Ukrainian🇧🇩Bengali🇲🇾Malay🇵🇭Filipino🇭🇷Croatian🇸🇰Slovak🇧🇬Bulgarian🇷🇸Serbian🇱🇹Lithuanian🇱🇻Latvian🇪🇪Estonian🇸🇮Slovenian🇦🇱Albanian🇲🇰Macedonian🇿🇦Afrikaans🇰🇪Swahili🇮🇷Persian🇵🇰Urdu🇰🇿Kazakh🏴󠁥󠁳󠁣󠁴󠁿Catalan🇮🇳Tamil

Works with the formats you already use.

PolyCLI supports the most common i18n and documentation file formats out of the box.

.json

JSON i18n

The standard format for React, Next.js, Vue, and most web frameworks.

.md

Markdown

Translate your .md docs and content files with full delta tracking.

.arb

Flutter ARB

Native support for Flutter's .arb files — translate your mobile app strings.

New

Translate documents. Preserve everything.

Upload a contract, report, or presentation directly from the dashboard. Get the translated file instantly — formatting intact, terminology consistent.

.docx

Word Documents

Fonts, layout, tables, and styles are fully preserved. Download the translated .docx in seconds.

.pdf

PDF Documents

PDF text is extracted, translated, and returned as clean, structured Markdown.

Glossary Applied

Your team glossary is used automatically — brand names and technical terms are never mistranslated.

Multi-language Export

Translate one document into multiple languages at once and download each file individually or all at once.

We store your translated files for 48 hours so you can download them at your own pace. After that, they are automatically and permanently deleted for your privacy.

Smart Intelligence. Better Translations.

PolyCLI understands your product before it translates it.

Context Analysis

Before translating, PolyCLI automatically scans your source files to detect your product's domain, audience, and terminology. This free step injects domain context into every translation prompt — no configuration needed.

Free — never charges creditsLearn more

Custom Glossary

Protect brand names and CLI commands from translation with a 100% guarantee, or guide the AI toward preferred terminology per language. Your product terms are never altered — in both CLI runs and document translations.

Learn more
New

Linguistic Quality Assurance

AI Reviewer Agent

Takes an existing translation and analyzes the text to identify faithfulness gaps, context errors, and unnatural phrasing. Highlights specific critical areas and returns a fully refined output.

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.

Document Translation

Upload .docx or .pdf files from the dashboard. Translated Word documents preserve formatting; PDFs return clean Markdown. Same credit model as the CLI.

Why PolyCLI?

See how it stacks up against the alternatives.

FeaturePolyCLIManualCloud SaaS
Cost per runPay per word (delta only)High (agency / freelancer)Subscription + per-word
Runtime overhead0 ms0 msVaries
Delta detection
Variable preservationVariesVaries
CI/CD nativeSometimes
Setup time< 5 minDaysHours

Works anywhere in your pipeline.

Drop it into any CI environment — no daemon, no config server.

GitHub Actions
Vercel
GitLab
CircleCI
Bitbucket
Netlify

Simple, honest pricing.

Pay per word translated. No subscription. Credits never expire.

Your first document translation is free — no credit card needed
Basic
Try it out
€5
  • 50,000 words translated
  • API key valid forever
  • Automatic variable preservation
  • Delta algorithm included
  • JSON + Markdown support
  • 1000 free words for new accounts
  • First document translation free
AI Reviewer included — optional, 3× credits only when a string is polished
Early Bird — 10 spots left
Starter
Perfect for indie devs
€8€15
  • 150,000 words translated
  • API key valid forever
  • Automatic variable preservation
  • Delta algorithm included
  • JSON + Markdown support
  • 1000 free words for new accounts
  • First document translation free
AI Reviewer included — optional, 3× credits only when a string is polished
Pro
For teams and larger projects
€39.99
  • 500,000 words translated
  • API key valid forever
  • Automatic variable preservation
  • Delta algorithm included
  • JSON + Markdown support
  • 1000 free words for new accounts
  • First document translation free
AI Reviewer included — optional, 3× credits only when a string is polished

Common questions