# FluentC API

> FluentC is a translation API built for agents and workflows. Translate text, HTML and JSON through a REST API, an MCP server, LangChain tools or an n8n node, in real-time or batch mode, with translation memory included.

- Base URL: https://api.fluentc.ai
- Authentication: send the API key in the Authorization header exactly as shown in the dashboard. Do not add a Bearer prefix.
- Requests and responses are JSON. Language codes are lowercase two- or three-letter codes such as es, fr, ja.
- Modes: real-time returns the translation in the response; batch returns a job_id that you poll.
- Consistency: the same text and target language return the same stored translation, whichever agent or model asks. Matches are exact, not fuzzy.

Every documentation page is also available as Markdown by replacing the trailing slash with `.md`, for example /docs/api/translate.md.

## Get started

- [FluentC API documentation](https://www.fluentc.ai/docs/index.md): Translate text, HTML and JSON from agents and workflows. Use the REST API, the MCP server, LangChain tools or the n8n node, in real-time or batch mode, with translation memory included.
- [Quickstart](https://www.fluentc.ai/docs/quickstart.md): Make your first real-time translation and your first batch translation in a few minutes, with cURL, Python or Node.
- [Authentication](https://www.fluentc.ai/docs/authentication.md): Authenticate every request with your API key in the Authorization header. No Bearer prefix. How to keep the key safe and what each authentication error means.
- [Concepts](https://www.fluentc.ai/docs/concepts.md): Real-time and batch modes, translation memory, input formats, language codes and how plans decide which mode a key can use.

## REST API

- [Translate](https://www.fluentc.ai/docs/api/translate.md): POST /ai_agent/translate. Translate text, HTML or JSON in real-time or batch mode. Request fields, response shapes, formats, and every validation error.
- [Batch results](https://www.fluentc.ai/docs/api/batch-results.md): POST /ai_agent/results. Fetch the result of a batch translation by job_id. The three statuses, polling guidance, and the one case where a wrong job_id looks like processing.
- [Detect language](https://www.fluentc.ai/docs/api/detect-language.md): POST /ai_agent/checklanguage. Identify the language of text or HTML without translating it.
- [Languages](https://www.fluentc.ai/docs/api/languages.md): GET /ai_agent/languages. List the languages enabled for your API key, to validate a language code before you translate or to populate a language picker.
- [Errors](https://www.fluentc.ai/docs/api/errors.md): Every HTTP status and error message the FluentC API returns, what causes it, and which ones are safe to retry.

## Integrations

- [Choose an integration](https://www.fluentc.ai/docs/integrations/overview.md): How to pick between the REST API, the MCP server, LangChain tools, the n8n node, Make and Zapier, and function calling, and what they all have in common.
- [MCP server](https://www.fluentc.ai/docs/integrations/mcp.md): Connect an MCP client such as Claude or Cursor to the FluentC MCP server, so an agent can translate on its own. Server URL, authentication, client configuration and troubleshooting.
- [LangChain tools](https://www.fluentc.ai/docs/integrations/langchain.md): The official fluentc-langchain-tool Python package. Install it, translate in real time or batch, detect languages, and give a LangChain agent FluentC as tools.
- [n8n node](https://www.fluentc.ai/docs/integrations/n8n.md): Install and use the FluentC n8n community node. Credentials, the Translate, Detect and Get Many operations, batch polling, limits and common workflows.
- [Make and Zapier](https://www.fluentc.ai/docs/integrations/make-zapier.md): Call FluentC from Make scenarios and Zapier Zaps with a plain HTTP step. Request settings, a real-time pattern, a batch pattern with polling, and tips for avoiding duplicate work.
- [Function calling](https://www.fluentc.ai/docs/integrations/function-calling.md): Let OpenAI, Anthropic, Gemini or any model with tool calling translate through FluentC. A tool definition, a handler that calls the REST API, and the full loop.

## Articles

- [Batch or real-time? Choosing a mode](https://www.fluentc.ai/articles/batch-or-real-time.md): Every FluentC request is either real-time or batch. A short guide to which fits which job, how the plans map to modes, and how to poll a batch job without waiting forever.
- [Giving a support agent a second language](https://www.fluentc.ai/articles/support-agent-second-language.md): Your support agent works in English. Your customers don't always write in it. How to add detection and translation around the agent, in about thirty lines, without changing the agent.
- [Ten agents, one translation](https://www.fluentc.ai/articles/ten-agents-one-translation.md): When every agent translates for itself, the same sentence comes out ten ways. Here is why that happens, what it costs, and how to make every agent return identical wording.

## Industries

Example agent flows for each industry, and where FluentC fits in them. Examples, not customer stories.

- [Healthcare](https://www.fluentc.ai/industries/healthcare/): Patient messages, intake forms and discharge instructions.
- [Financial services](https://www.fluentc.ai/industries/financial-services/): Support, statements and disclosures across every channel.
- [E-commerce & retail](https://www.fluentc.ai/industries/ecommerce/): Catalogs, order updates and shopper chat.
- [Travel & tourism](https://www.fluentc.ai/industries/travel/): Itineraries, policies and guest messages.
- [Technology & software](https://www.fluentc.ai/industries/technology/): UI strings, docs and in-product help.
- [Legal](https://www.fluentc.ai/industries/legal/): Client intake and document triage.
- [Manufacturing](https://www.fluentc.ai/industries/manufacturing/): Work instructions, safety notices and supplier messages.
- [Automotive](https://www.fluentc.ai/industries/automotive/): Owner Q&A, service scheduling and parts catalogs.
- [Government & public sector](https://www.fluentc.ai/industries/government/): Resident services, public notices and forms.
- [Non-profit & NGO](https://www.fluentc.ai/industries/nonprofit/): Field reports, appeals and program materials.

## Optional

- [OpenAPI specification](https://www.fluentc.ai/docs/openapi.yaml): machine-readable description of the REST API
- [All documentation in one file](https://www.fluentc.ai/llms-full.txt): every page above, concatenated
- [Documentation home](https://www.fluentc.ai/docs/): the human-readable docs
- [Enterprise](https://www.fluentc.ai/enterprise/): why many agents on different models return one translation
- [Pricing](https://www.fluentc.ai/pricing/): the Standard (Batch) and Pro (Real-time) plans, monthly or annual
- [Contact](https://www.fluentc.ai/contact/): ask a question