I1n Cli MCP Server

i1n

Your app in every language. One command.

Localization as code. Push your translation keys, AI translates to 182 languages, pull type-safe TypeScript definitions. Built for developers, AI agents, and product teams.

Free forever · No credit card · i1n.ai

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Why i1n?

Traditional i18n means dozens of JSON files, zero type safety, hours of copy-pasting, and deploys that break at 2 AM. Existing tools charge $120+/mo and require browser-based workflows.

i1n is different:

• One command — i1n push --translate es,fr,ja and you're done
• Type-safe — auto-generated i1n.d.ts with full IDE autocomplete
• AI-native — MCP server for Cursor, Claude Code, Windsurf. Your agent handles i18n for you
• Zero migration — Bridge Mode wraps your existing i18next/next-intl/vue-i18n
• 6x cheaper — Free tier included. Pro at $19/mo vs Lokalise at $120/mo

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📦 Install

# To use the CLI (global)
npm install -g i1n

# To use the SDK + types (in your app)
npm install i1n

# Local CLI usage (optional)
npm install -D i1n

Supports npm, pnpm, yarn, and bun.

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🏁 Quick Start

# 1. Initialize (auth + auto-detect setup)
i1n init

# 2. Push your translation keys
i1n push

# 3. Pull translations + auto-generated TypeScript types
i1n pull

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✨ Key Features & Commands

🛠️ i1n init

Interactive setup that prepares your workspace.

• Authenticates via API key.
• New? If you don't have a key yet, the CLI provides clear guidance on how to get started.
• Auto-detects frameworks (Next.js, Vite, Expo, Flutter, Rails, etc.).
• Saves configuration to i1n.config.json (automatically ignored via .gitignore).
• AI Orchestration: Optionally sets up rules for your AI coding tools.

⬆️ i1n push

Syncs your local translations to i1n.

• Detects new keys and source changes.
• Smart Translate: Offers to translate missing keys with a cost estimate before proceeding.
• Efficient caching layer — repeated translations cost a fraction of fresh ones.
• Three-way diff — push only sends the (key, lang) pairs you actually changed, never overwriting edits made via the dashboard or by other teammates. See Team workflow for the full conflict model.

Flags:

• --translate [langs] — trigger AI translation after push (e.g. --translate es,fr,ja)
• --strategy <mode> — how to handle real conflicts: interactive (default in TTY), ours, theirs, abort
• --force — shorthand for --strategy ours (overwrite the server with your local values; destructive)

⬇️ i1n pull

Downloads translations and generates type-safe IDs.

• Updates local locale files in your configured format.
• Generates i1n.d.ts for full IDE autocomplete.

📊 i1n limits

Real-time usage tracking.

• View your current plan and credit usage.
• Monitor active language slots and available capacity.

🧠 i1n setup-ai

Turns your IDE into a localization expert.

• Generates project-specific rules for Cursor (.mdc), Claude Code (CLAUDE.md), Windsurf, and more.
• Ensures AI agents follow your naming conventions, file structure, and brand voice.

🔌 i1n mcp

MCP server for AI coding assistants.

Starts a Model Context Protocol server that lets Cursor, Claude Code, Windsurf, and other AI assistants execute i1n commands directly from your IDE.

# Add to Claude Code
claude mcp add i1n -- npx i1n mcp

# Or add to .mcp.json / cursor config

{
  "mcpServers": {
    "i1n": {
      "command": "npx",
      "args": ["i1n", "mcp"]
    }
  }
}

8 tools available:

The killer workflow — tell your AI agent "internationalize this component":

1. The agent reads your file and identifies hardcoded strings
2. It calls i1n_extract_and_translate with the extracted strings
3. i1n pushes the keys, translates to all active languages, generates types
4. The agent rewrites your component with t('key') calls

A 60-minute task in 30 seconds.

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👥 Team workflow

i1n is designed for teams where multiple people edit translations in parallel — devs in different branches, copywriters in the dashboard, AI agents via MCP. i1n push is safe to run without worrying that your local working tree might pulverize someone else's edits.

How push decides what to send

Before every push, the CLI:

1. Reads your local locale files (L).
2. Asks the server which keys exist and when each was last modified (cheap metadata-only call, ~50× smaller than a full pull).
3. If anything moved on the server since your last sync, fetches the full server state (S).
4. Computes a three-way diff per (namespace, key, lang) against the last baseline you synced (P, stored in locales/.i1n-push-state.json).

For each (key, lang) the diff places it in one of these buckets:

Only the languages that genuinely changed locally are sent. Languages you didn't touch are not in the payload, so the server's per-language merge preserves them. No more "my push silently overwrote yield_rate that I never even opened".

When there's a real conflict

A real conflict means you and someone else both edited the same (key, lang) to different values since the last sync. The CLI shows each one and asks you to pick:

Conflict 1/3: common.greeting [en_us]

  › Keep local: "Hello there"
    Accept server: "Hi"
    Abort push

• Local → push your value, overwrite the server.
• Server → discard your local, auto-pull the server's value into your file.
• Abort → exit; nothing is pushed.

For batch / CI / non-interactive environments, pass a strategy:

i1n push --strategy theirs   # accept all server values, push nothing for conflicts
i1n push --strategy ours     # local wins (alias: --force)
i1n push --strategy abort    # exit on any conflict

In non-TTY contexts (e.g. CI without a strategy flag), push aborts with a diff of the conflicts so you can resolve in code.

Auto-pulling server-only changes

If a teammate or someone in the dashboard updated a key you never touched, the server's value is automatically written into your local file at push time and your i1n.d.ts is regenerated if needed. Your working tree ends up reflecting reality — your git diff will show the bring-in so you can commit it alongside your own changes.

MCP push (AI agents)

The MCP i1n_push tool runs the same diff but defaults to abort on conflict because an AI agent should not silently pick a winner. Conflicts are reported in the response so the agent can decide to pull, ask you, or resolve manually before retrying.

Fresh checkouts

locales/.i1n-push-state.json is gitignored by design — it's working-tree state, like .git/index. On a fresh clone or new branch where the file doesn't exist, the baseline is synthesized from the server. Any local divergence from the server is then treated as a conflict (the CLI can't tell whether you edited locally or have stale data). Run i1n pull first if you just cloned and want to bring everything in cleanly.

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📁 Supported Formats

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🧩 SDK Usage

The i1n package includes a runtime SDK for web and mobile JS/TS projects. You can use it in two ways:

Standalone Mode — Replace your i18n library

Use the i1n native engine directly. No external dependencies needed.

import { init, t, setLocale } from "i1n";

// Load your translation resources
init({
  locale: "en_us",
  resources: {
    en_us: {
      auth: { login: "Login", title: "Welcome back, {user}" },
      items_one: "One item",
      items_other: "{count} items",
    },
    es_es: {
      auth: { login: "Entrar", title: "Bienvenido de nuevo, {user}" },
      items_one: "Un elemento",
      items_other: "{count} elementos",
    },
  },
});

// Autocomplete and type-safety work out of the box after 'i1n pull'
t("auth.login"); // "Login"

// Support for default values (useful during development)
t("new.key", { defaultValue: "Coming soon..." }); // "Coming soon..."

// Variables & Plurals
t("auth.title", { user: "Fran" }); // "Welcome back, Fran"
t("items", { count: 5 }); // "5 items"

// Switch language at runtime
setLocale("es_es");
t("auth.login"); // "Entrar"

Key resolution works with both nested and flat structures automatically — use whatever format your project prefers.

Bridge Mode — Keep your library, add type safety

Already using i18next, vue-i18n, or react-intl? Connect it to i1n with one line and get full autocompletion.

import i18next from "i18next";
import { registerI1n, t } from "i1n";

// Set up i18next as usual
await i18next.init({
  lng: "en",
  resources: {
    /* ... */
  },
});

// Connect to i1n — one line
registerI1n((key, params) => i18next.t(key, params));

// Now t() uses i18next under the hood, but with strict type checking
t("common.greeting", { name: "World" }); // Powered by i18next, typed by i1n

Works with any library:

• vue-i18n: registerI1n((key, params) => i18n.global.t(key, params))
• react-intl: registerI1n((key, params) => intl.formatMessage({ id: key }, params))
• Custom: registerI1n((key) => myLookup(key))

Pluralization

Define plural variants with _zero, _one, _other suffixes:

// In your translation files:
// "items_zero": "No items"
// "items_one": "One item"
// "items_other": "{count} items"

t("items", { count: 0 }); // "No items"
t("items", { count: 1 }); // "One item"
t("items", { count: 5 }); // "5 items"

Interpolation

Three syntaxes supported universally: {var}, {{var}}, %{var}

JavaScript (without TypeScript)

The SDK works in plain JS — you just don't get autocompletion:

import { init, t } from "i1n";
init({ locale: "en_us", resources: { en_us: { greeting: "Hello {name}" } } });
t("greeting", { name: "World" }); // "Hello World"

⚛️ React / Preact Integration

For a "plug and play" experience, use this minimalist provider pattern.

import { createContext, useContext, useState, useEffect } from "react";
import { init, t, getLocale, setLocale as sdkSetLocale } from "i1n";

// 1. Initialize with wordings
// (In a real app, you'd probably import these from your locales folder)
init({
  locale: "en_us",
  resources: {
    /* ... */
  },
});

const STORAGE_KEY = "i1n-locale";
const I1nContext = createContext({
  locale: "en_us",
  setLocale: (l: string) => {},
});

// 2. Persistent Provider
export function I1nProvider({ children, defaultLocale = "en_us" }) {
  const [locale, setLocaleState] = useState(() => {
    return localStorage.getItem(STORAGE_KEY) || defaultLocale;
  });

  // Keep SDK in sync
  useEffect(() => {
    sdkSetLocale(locale);
  }, [locale]);

  const setLocale = (newLocale: string) => {
    localStorage.setItem(STORAGE_KEY, newLocale);
    setLocaleState(newLocale);
  };

  return (
    <I1nContext.Provider value={{ locale, setLocale }}>
      {children}
    </I1nContext.Provider>
  );
}

// 3. Simple Hook
export const useI1n = () => ({ t, ...useContext(I1nContext) });

Usage:

const { t, setLocale } = useI1n();

return (
  <div>
    <h1>{t("auth.title", { user: "Fran" })}</h1>
    <button onClick={() => setLocale("es_es")}>Español</button>
  </div>
);

Non-JS Platforms

Flutter, Android, and iOS projects don't use the SDK. They use the translation files (.arb, .xml, .strings) generated by i1n pull with their native localization systems.

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🛡️ Developer Experience

🔒 Privacy & Security

• Auto-Ignore: i1n init automatically adds sensitive config files to your .gitignore.
• Secret Management: API keys are only stored locally and never committed to version control.
• Encrypted Transmission: All sync operations happen over secure HTTPS channels.

🔒 Zero-Config Type Safety (TypeScript)

The CLI generates a lightweight declaration file (i1n.d.ts) that automatically augments the i1n package with your project's specific keys.

1. Pull: Run i1n pull. The CLI generates locales/i1n.d.ts and automatically updates your tsconfig.json so your IDE finds them immediately.
2. Usage: Import t from i1n and get full autocomplete + compile-time checking. No manual path mapping required.

import { t } from "i1n";

// Full autocomplete & compile-time checking
t("auth.login.title");

// ERROR: Argument of type '"auth.login.titlse"' is not assignable...
t("auth.login.titlse");

// Dynamic strings still pass through — useful for `t(item.name)`,
// runtime-built keys, etc.
declare const dynamicKey: string;
t(dynamicKey);

Strict literal checking landed in 1.3.0: passing a hard-coded string that isn't in I1nKeys is now a TypeScript error (no more silent [i1n] Missing translation warnings at runtime). Variables typed as string keep working without casts.

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💳 Pricing

CLI, SDK, and MCP server are free on every plan. No credit card required for Starter.

Pro lifetime from $99 — only for the first 200 users.

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📄 License

MIT — © 2026 i1n.ai