---
title: AI JSON Translator | Scale Enterprise-Quality Translations
description: Translate JSON locale files into 280+ languages. Keys, placeholders and nesting stay intact; translation memory covers every release. Free 15-day trial.
canonical: https://www.smartcat.com/json-translator/
language: en
updated: 2026-08-22
---

# AI JSON Translator | Scale Enterprise-Quality Translations

## JSON Translator: Translate Locale Files Without Breaking Keys

Smartcat parses your JSON, translates only the string values, and returns a file with the same keys and the same nesting — with your placeholder tokens locked as tags, using regex rules you define once — in any of 280+ languages.

- [Book a demo](https://www.smartcat.com/book-a-demo/?n-upl)

- [Sign up free](https://smartcat.com/sign-up?n-upl)

## What a JSON Translator Has to Preserve

A JSON translator converts the human-readable strings in a JSON file into another language without touching the file’s structure. Smartcat translates the string values in your locale files — keys, numbers, booleans and nesting stay exactly as they were, and placeholder tokens are locked as non-editable tags — so the translated file drops back into your i18n pipeline.

Just translating one file, once, for free? Use the [free JSON translator](https://www.smartcat.com/software-translator/translate-json-free/) — it’s the same engine with a browser-first flow.

### 280+

### target languages

One en.json in; de.json, ja.json and pt-BR.json out. Keep en.json as your source of truth and generate every target locale from it in one project, instead of maintaining twelve files by hand.

### 103%

### key-ID TM matches

Strings keep their key IDs, so translation memory can match the segment and its key — a level of reuse ordinary document formats, capped at 102% context matching, cannot reach.

### 6 GB

### per document or project file

The published ceiling is a global one, not JSON-specific, with guidance to split anything over 1 GB into smaller parts for speed.

## Why JSON Files Break in Ordinary Translators

- [Get started](https://smartcat.com/sign-up)

Paste an en.json into a generic translator and it treats the whole document as prose. What comes back parses in your editor — or doesn’t — and fails in production.

**Keys get translated** — "checkout_button" becomes "bouton_de_paiement" and every lookup in your code now returns undefined.

- **Placeholders get mangled** — "Hello, {{userName}}" comes back as "Bonjour, {{nomUtilisateur}}" and the string renders with a raw token because the variable no longer resolves.

- **Plural forms collapse** — an ICU message like {count, plural, one {# item} other {# items}} gets flattened into a single sentence, and pluralization silently breaks for every language that isn’t English.

- **Escaping corrupts** — escaped quotes, \n and \uXXXX sequences are "helpfully" normalized, and the file that looked fine in a diff throws at JSON.parse.

None of these show up in review. They show up at runtime, one locale at a time. Working with other developer formats? Smartcat also parses [gettext PO files](https://www.smartcat.com/gettext-po/) and XLIFF in the same workspace, sharing one translation memory and glossary.

left

### One source

### One source file, every locale generated from it

Keep en.json as the source of truth and generate — and regenerate — every locale from it in one project. Export whole projects in one action: select them, click Download, and get one ZIP with every file in its original format, sorted into folders.

- [Sign up](https://smartcat.com/sign-up?json-translator_tabs-carousel)

### Reuse

### Release two is mostly work you’ve already done

Translation memory stores every segment; JSON key IDs push matches to 103%. Ship v2 with 40 edited strings of 3,000 and 2,960 return from the TM.

**Update current document** recovers TM work but cancels task assignments; both Update and Upload consume Smartwords for retranslation.

- [Learn about software localization](https://www.smartcat.com/software-localization/?json-translator_tabs-carousel)

### Consistency

### Product terms stay consistent across every key

A glossary enforces that your feature is called the same thing in nav.title and onboarding.step3.body, and QA flags any segment where it isn’t. Linguistic assets attach at project level and apply to every document, with one writable translation memory per language pair.

- [Get started](https://www.smartcat.com/marketplace)

### Automation

### Automate it from your pipeline

Pull and push locale files via the Smartcat API: **Anticipate and Autonomous plans**, company accounts only, no trial. Basic auth, 4 requests/second, CLI for CI/CD. Docs: [API guides](https://developers.smartcat.com/api-guides/), [API reference](https://developers.smartcat.com/api/).

Same project: [XML and strings.xml](https://www.smartcat.com/xml-translator/), [XLIFF](https://www.smartcat.com/xliff-translation-editor/), [YAML](https://www.smartcat.com/yaml-translator/), PO/POT, RESX.

- [Get started](https://smartcat.com/sign-up?json-translator_tabs-carousel)

### What survives

### What survives translation, and what needs your attention

Keys aren’t translated; they carry key IDs, unlocking 103% matching. Numbers, booleans, null and nesting return untouched.

Set a regex per token format in Settings → Placeholders before first import, or tokens stay text. Plurals export as ICU MessageFormat; categories differ (Russian four, Japanese one).

- [Get started](https://smartcat.com/sign-up?json-translator_tabs-carousel)

## Trusted With Product Content by 1,000+ Enterprise Brands

### 9.6/10

for ease of setup on G2

### 9.3/10

for ease of use on G2

### 1,000+

enterprise brands

### SOC 2

Type II compliant

It all starts with a call

Bring one real locale file to a 1:1 with a localization engineer: XPaths, placeholder rules and your release cadence, worked through on your own file. No commitment.

- [Book a personalized demo](https://www.smartcat.com/book-a-demo/?from_excel-translator)

## How to Translate a JSON File in Smartcat

### 1. Upload your locale file

Upload en.json — or several locale files at once.

### 2. Define your placeholder rules

On the Placeholders tab in Settings, add a regular expression for each token format your codebase actually uses. Anything matching is imported as a locked, non-editable tag — the same mechanism covers JSON, TJSON, PO, RESX, XLIFF, XML, PHP and CSV.

### 3. Pick target languages

One file in, de.json, ja.json and pt-BR.json out, from 280+ options.

### 4. Review what matters

Open the editor to check strings, enforce glossary terms, or route a language to a human reviewer. Skip it when the AI draft is enough.

### 5. Download JSON

Same keys, same nesting, new language.

### 6. Or export the whole project at once

Select your projects, click Download, and you get a single ZIP with every file in its original format, sorted into folders.

- [Start Translating Files Today](https://smartcat.com/sign-up?excel-translator)

## JSON Translation Results Teams Have Published

### 2–3 days

### Document turnaround, down from ten

Smith+Nephew cut translation turnaround from 10 days to [two to three days](https://www.smartcat.com/cases/smith-nephew/) with Smartcat.

- [Read case study](https://www.smartcat.com/cases/smith-nephew/)

### 30%

### More translation output

Find out how Wunderman Thompson translates 30% more content without extending their budget while increasing quality.

- [Read case study](https://www.smartcat.com/cases/wunderman-thompson/)

### 31 hours

### Saved every month

Babbel saves 31 hours a month across its [marketing and L&D departments.](https://www.smartcat.com/cases/babbel/)

- [Read case study](https://www.smartcat.com/cases/babbel/)

Ship Every Locale From One Source File

Upload en.json, download every other locale — keys, placeholders and nesting intact, and release two reuses almost everything release one taught the translation memory. 15 days, no credit card.

- [Translate JSON Files Now](https://smartcat.com/sign-up?excel-translator_bottom-cta)

## Frequently Asked Questions

### What is a JSON file?

A JSON file (JavaScript Object Notation) is a lightweight, text-based format for storing and exchanging structured data. It’s commonly used for sharing information between web applications and servers because it’s easy for humans and machines to read and write. JSON files typically use key-value pairs and support data types like strings, numbers, arrays, and objects.

### Will the output actually parse?

Structure is never edited — only string values are — so validity comes from the parse model rather than from luck. Smartcat separates structure from content: keys, numbers, booleans, nulls and nesting are locked, and only string values become translatable segments.

### How does Smartcat handle nested objects?

Nested object structures are supported and their shape is preserved. Strings carry their key IDs through the project, which is what lets translation memory match on the key as well as the text.

### Does it support ICU MessageFormat plurals?

Yes, in both directions. Plurals can live in Smartcat either natively — each plural form as its own segment, created with all forms when you add the key — or as ICU MessageFormat syntax. On import you choose whether keys containing ICU syntax are parsed into individual segments or left as they are, and on export plural forms are written back as an ICU MessageFormat-compatible string.

### Can I translate only the keys that changed since the last release?

Effectively yes. Use **Update current document** on the changed file: it replaces the file and pulls all existing translation work back out of the translation memory, so only new and edited strings are real work. Two caveats worth knowing before you rely on it — the update cancels any task assignments on that document, so linguists must be reassigned, and both Update and Upload consume Smartwords for retranslation.

### Which JSON conventions work?

Standard key-value JSON and nested objects are both documented as supported, and LOCJSON and TJSON are supported as separate formats in their own right.

### Is there a file size or file count limit?

The published ceiling is a global one, not a JSON-specific one: **6 GB per document or project file**, with guidance to split anything over **1 GB** into smaller parts for speed. No string-count limit is documented.

There is **no cap on how many files** go into one project — batch uploads of hundreds of locale files are supported, and the limit does not change by plan. The constraint is **per-file size, not file count**.

### Is there an API for JSON translation?

Yes, on the **Anticipate and Autonomous** plans, and it needs a **company account** — the API cannot be used from a freelancer account, and it is **not switched on during the free trial**.

It uploads files, retrieves translations, and supports async processing with notification callbacks; every method shares a **4 requests/second** rate limit. Docs: [developers.smartcat.com/api-guides/](https://developers.smartcat.com/api-guides/).

### Is my source content safe?

Smartcat is SOC 2 Type II compliant. Files are encrypted in transit and at rest, workspaces are isolated, and access is role-based. Details on the [security page](https://www.smartcat.com/security/).

### Where does JSON machine translation fall short?

Machine translation can’t infer UI context from a key name. **"Save"** might be a button, a discount, or a noun — and the right translation differs in most languages.

For strings under about **three words** the AI draft is a starting point; the segment editor exists precisely so a human can check them against screenshots or context notes before release. **Budget review time for short UI strings**; skip it for long descriptive text.