FluentC API

Translation built for the way you actually build now.

FluentC was designed for what translation is now: an agent calling an API thousands of times an hour, in the middle of a workflow, expecting an answer back before the user notices.

Running more than one agent? Get the same translation from every one →

Mika TanakaSupport · Order #4821
ja ⇄ en
  1. My order hasn't arrived yet.

    注文した商品がまだ届いていません。

  2. Sorry about that, Mika. It shipped yesterday and should arrive tomorrow.

    Mika seesご不便をおかけして申し訳ありません、ミカさん。昨日発送済みで、明日届く予定です。

  3. Thank you so much!

    ありがとうございます!

Reply in English. Mika reads Japanese. Translated by FluentC
Example conversation. Names and order are made up.

Works where you build

  • n8n
  • LangChain
  • OpenAI
  • Claude
  • Cursor
  • and anything that sends HTTP
Built for more than one agent

Ten agents. Different models. One translation.

When every agent translates for itself, the same sentence comes out ten ways. Put FluentC in the loop and they all return the same one, whichever model is behind them.

How it stays the same

Source textYour order has shipped and will arrive on Thursday.Target: es

Each agent translates for itself

4 versions
  • Support agent Model ASu pedido ha sido enviado y llegará el jueves.
  • Sales agent Model BTu pedido fue enviado y llegará el jueves.
  • Onboarding agent Model CHemos enviado su pedido; lo recibirá el jueves.
  • Billing agent Model DSu envío está en camino y llegará el jueves.

…and every other agent adds a version of its own.

All agents call FluentC

1 version
  • Support agent Model ASu pedido ha sido enviado y llegará el jueves.
  • Sales agent Model BSu pedido ha sido enviado y llegará el jueves.
  • Onboarding agent Model CSu pedido ha sido enviado y llegará el jueves.
  • Billing agent Model DSu pedido ha sido enviado y llegará el jueves.

…and every other agent returns the same one.

  • One translation
  • Any model
  • Reviewed once
Illustrative: the variants are plausible phrasings, not output from named models. With FluentC, the first request translates the text and later requests return the stored translation.
Four ways in

Same engine. Call it the way your stack already works.

Industries

Agent flows for your industry.

All ten industries →
Patient messages, intake forms and discharge instructions.
Example agent flow

Patient message triage

A patient writes in their language. A triage agent works in English. A nurse reviews.

  1. Patient message
  2. Triage agent
  3. FluentC, both ways
  4. Nurse queue
  5. Reply sent

With FluentC in the loop

  • The triage agent works in English while the patient reads their own language, and every agent gets identical wording for the same instruction.
  • A nurse reviews a phrase once. The words that were reviewed are the words every agent sends next.
See the Healthcare flows

Example flows, not customer stories.

Articles

Translation, in the flow of the work.

All articles →
Questions

Things people ask.

Short answers, with links to the longer ones.

Something else? Ask us →
What is FluentC?
A translation API built for agents and workflows. You send text, HTML or JSON and a target language, and get the translation back through REST, an MCP server, LangChain tools or an n8n node. If you want to translate a website instead, see FluentC for websites.
How do I connect it to my agent?
Pick the integration that matches how you build: MCP for agents that use tools, LangChain for Python agents, n8n for workflows, REST for everything else. They share one API key and one translation memory. See integrations.
Should I use real-time or batch?
Real-time returns the translation in the response, for anything a person is waiting on. Batch returns a job ID that you poll, for catalogs, UI strings and content libraries. Choosing a mode has the short version.
What does “the same translation every time” mean?
The same text and target language return the same stored translation, whichever agent or model asks. The match is exact, not fuzzy. The enterprise page explains how it works and what it doesn't promise.
How many languages are there?
128+ languages, addressed by lowercase ISO codes such as es, fr and ja. Which of them your key can use depends on your account, and the languages endpoint lists them.
What does it cost?
Two plans, billed monthly or annually. Standard (Batch) is $10 a month or $100 a year, and Pro (Real-time) is $95 a month or $950 a year. Translation memory is included in both. See pricing.
Fluency

Fluent is the point.

Most translation APIs were designed when "translation" meant a human pasting text into a web form. Output here reads like a native speaker wrote it, and comes back fast enough to sit inside a user-facing request.

  • esTu pedido ha sido enviado.
  • jaご注文の商品は発送されました。
  • deIhre Bestellung wurde versandt.
  • frVotre commande a été expédiée.
  • ptSeu pedido foi enviado.
  • ko주문하신 상품이 발송되었습니다.
128+ languagesPass an ISO language code. The languages endpoint lists what's enabled for your key.
  • esEspañol
  • frFrançais
  • deDeutsch
  • ptPortuguês
  • itItaliano
  • nlNederlands
  • ja日本語
  • ko한국어
  • zh中文
  • hiहिन्दी
  • arالعربية
  • heעברית
  • ruРусский
  • plPolski
  • trTürkçe
  • viTiếng Việt
  • thไทย
  • idBahasa Indonesia
  • svSvenska
  • ukУкраїнська
  • elΕλληνικά
  • swKiswahili
  • bnবাংলা
  • taதமிழ்
  • and many more

We're the scrappy alternative to the giants.

That's on purpose.