Ship Every Release in 280+ Languages — Free API Access for 15 Days
Test the real integration before you commit. Your free 15-day trial includes API access and 15,000 Smartwords, with no credit card — generate a key, point your pipeline at it and judge the endpoints and the translation quality on your own files.
The API guides and the full reference are public, with no signup wall. Read first, then build.
Trusted by developers and localization teams at 1,000+ enterprise brands
Evaluate Smartcat Free, Then Integrate
The trial, the documentation and a scoping call with an engineer all cost nothing — and the trial includes API access, so you can evaluate the integration itself, not just the output.
15 days
free trial, API included
Generate an API key, run your own files through your own code and spend the 15,000 included Smartwords however you like. You are calling the same endpoints, translation memory and glossaries a paid account calls — no credit card required.
4 req/s
rate limit, every method
The same limit on every method and every plan, documented publicly in the rate limits section of the guides. Heavy operations are asynchronous with webhook callbacks, so it caps request volume, not how much content you can push.
50+
file formats, no reduced API set
The API reaches the same formats the platform supports. Software localization adds json, structured-json, yaml, structured-yaml, ios-strings and android-xml. Executables and scripts are blocked for security.
Start with the free trial
15 days, 15,000 Smartwords, no credit card — API access included. Create a key, wire up a test project and push your real locale files, release notes or product docs through it. You are evaluating the integration and the translation quality at the same time.
Read the docs while you test
The API guides and the full API reference are public with no signup wall. The auth model, every endpoint, the async/callback model and the 4 requests/second limit are inspectable up front.
Move to a paid plan when you’re ready
When the trial ends, API access continues on the Anticipate and Autonomous plans. Prices are on the pricing page, visible without a sales call, and a scoping call sizes the plan against your real volume.
Translate files, not just strings
Create a project and send your file as a multipart request, then poll the project for status and export the translation when it’s done.
Long-running work is asynchronous by design — the API answers 202 IN PROGRESS — and you can register notification callbacks (webhooks, with custom headers) so your pipeline gets told instead of polling.
There is also a real-time endpoint when you genuinely do need a synchronous string back.
Translation memory, glossaries and human review
Segments your account has translated before are reused, and glossary terms are enforced — so a CI job translating release N+1 spends its linguistic effort only on what changed.
The same platform the API feeds includes review workflows and a marketplace of vetted linguists, a quality path a raw MT endpoint does not have.
There is also a Smartcat CLI intended for CI/CD pipelines, so a build step can push source files and pull translations without anyone writing an HTTP client.
File-level, not per-string
A general MT API prices and processes per character, per call. Locale files have structure to preserve, product terms to keep consistent and heavy overlap between releases.
Smartcat works at the file and project level: structure protection for JSON and XML, glossary enforcement and translation memory reuse across every release and every format.
Authentication and Setup, in Three Steps
1
Generate a key in Settings > API
As an administrator, open Settings > API. Your username is the string in the Account ID field; your password is an API key you create with CREATE NEW KEY. Multiple keys are allowed, and trial accounts can create them too.
2
Send Basic auth on every call
Base64-encode accountId:apiKey and send it as the Authorization header. The API uses HTTP Basic authentication on every method.
3
Call your regional base URL
https://smartcat.ai/api/integration/v1/… for Europe, us.smartcat.ai for the Americas, ea.smartcat.ai for Asia. The documented quickstart is POST /api/integration/v1/project/create as a multipart request with your file. A public Postman collection is available on GitHub.
Why 4 requests per second is not a volume ceiling
Because the heavy operations are asynchronous (202 IN PROGRESS) and can call you back via webhooks, the rate limit caps request volume, not how much content you can put through.
How do API credentials work?
Credentials are per-account: an Account ID plus API keys you generate in Settings > API, and you can hold more than one key. Trial accounts can generate keys, so you authenticate exactly as a paid account does from day one.
What should I test first?
Put your hardest content through the trial: the format you ship most, your product terminology, your longest release file. Smartcat earns its place on recurring, multi-format, multi-language work, where translation memory reuse and review workflows compound with every release.
Why Teams Trust Smartcat With Production Localization
The API feeds the same platform 1,000+ enterprise brands already localize on, with review workflows, a marketplace of vetted linguists and SOC 2 Type II controls behind every call.
for simple setup
for ease of use
enterprise brands
languages available
Scope This Against Your Pipeline
Run the trial against your own pipeline first, then bring the results to the call: the formats you ship, your release cadence and your peak volume. 4 requests per second sizes very differently for nightly batches than for on-demand calls, and that is the first thing we will work out with you.
What Automated Localization Pipelines Deliver
50%
increase in productivity
expondo increased productivity by 50% while reducing outsourcing costs by 50%, localizing in-house with Smartcat’s integrated platform.
1,000 hours
Admin time saved yearly
The City of Seattle saved about 1,000 hours of yearly administrative and project-management time by automating paperwork and payment for the 50+ community reviewers it works with, and cut translation expenses by 17%.
31 hours
Of work time saved monthly
Babbel’s marketing and L&D teams save 31 hours of work time every month, time they can now use for more strategic work.
Enterprise-Grade Security for Your Code
Smartcat is SOC 2 Type II compliant; content is encrypted in transit and at rest, and workspaces are isolated. Details on the security page.
Try It Free, Read the Docs, Then Book the Call
The guides and the full API reference are public — read them before you talk to anyone. The 15-day trial is free, needs no credit card and includes API access, so you can make real calls against your own files in parallel.
What the scoping call covers, in four parts:
- Which endpoints your pipeline would call, and whether the CLI covers your CI job.
- Whether 4 requests per second fits your real file counts, languages and release cadence.
- Which plan you’d be on, and what it costs.
- Which parts of the platform your team will use alongside the API — review workflows, marketplace linguists, connectors.
It’s an engineer-facing 1:1 — bring your engineer and ours will be on the call.
Frequently Asked Questions
Is the Smartcat translation API free?
You can use it free during the 15-day trial: API access is included, along with 15,000 Smartwords and no credit card. After that it continues on the Anticipate and Autonomous plans. The API guides and full reference are public with no signup wall.
What does the free trial include?
15 days, 15,000 Smartwords and API access, no credit card. Generate a key in Settings > API and call the same endpoints a paid account calls, so you can test the integration and the translation quality on your own files at once.
How can I evaluate the API before I buy?
Start the trial and build against it. Generate a key, point your pipeline at your regional base URL and run your real files through the endpoints you would use in production — same translation memory, same glossaries. Read the public guides and reference alongside it, and book a scoping call when you want a second pair of eyes on the design.
Which plans include API access?
The 15-day trial, then Anticipate and Autonomous. Plan details and prices are on the pricing page — visible without a sales call.
Which file formats can I translate through the API?
The same 50+ formats the platform supports — there is no reduced API set. That covers: Office and OpenOffice documents, TXT and RTF; HTML, XHTML, PHP and JS; bilingual CAT formats (XLIFF 1.2 and 2.0, SDLXLIFF, MQXLIFF, PO, TTX); DTP files (PDF, MIF, INDD, IDML, CSV); DITA and Help+Manual XML; and software-localization resource formats (XML, Android XML, RESX, LOCJSON, JSON, TJSON, YML, INC, INX, STRINGS, PROPERTIES).
Executables and scripts are blocked for security.
What are the rate limits and quotas?
4 requests per second, applied to every Smartcat API method. Exceed it and you get 429 TOO MANY REQUESTS. There is no per-plan differentiation, and it is documented publicly in the rate limits section of the API guides.
Because the heavy operations are asynchronous (202 IN PROGRESS) and can call you back via webhooks, 4 rps is a limit on request volume, not on how much content you can put through.
Where are the API docs?
Public, at developers.smartcat.com, with no signup wall — API guides for the how-to and the API reference for the endpoint-by-endpoint detail.
Is my content secure in the pipeline?
Smartcat is SOC 2 Type II compliant; content is encrypted in transit and at rest, and workspaces are isolated. Credentials are per-account: an Account ID plus API keys you generate in Settings > API, and you can hold more than one key. Details on the security page.
Can I translate into multiple languages at once?
Yes. A project can carry multiple target languages, and you export a translation per language. Because the heavy operations are asynchronous, your pipeline can register a notification callback rather than polling for each one.
How do I handle continuous updates and new strings?
There is a Smartcat CLI intended for CI/CD pipelines, so a build step can push source files and pull translations without anyone writing an HTTP client. Translation memory means release N+1 spends its linguistic effort only on what changed, and glossary terms stay enforced across releases.