Answers to the questions people ask before and after connecting an AI agent to file-convert.online. For the tool reference see the README at file-convert.online/blog/file-convert-mcp-server-readme; to get going in minutes see file-convert.online/blog/file-convert-mcp-server-quickstart.
What is an MCP server, and how is it different from the REST API?
MCP (Model Context Protocol) is the open standard AI clients use to discover and call tools. Instead of you writing code against our REST endpoints, the agent reads the tool list, understands from the descriptions what each tool does and calls them on the user's behalf. The MCP server is a thin layer over the same REST API, so nothing is possible in one that is impossible in the other; the difference is who does the integration work. Use REST from your own code, use MCP from Claude, Cursor, VS Code, Windsurf, n8n or any other MCP client.
How do I get an API key?
Create a free account on file-convert.online, sign in, and open file-convert.online/account/api-keys. Click Create key; the key (fc_live_...) is shown once together with ready-made client snippets, so keep it somewhere safe. The same page lists and revokes keys. Programmatic creation through POST /api/identity/v1/api-keys is documented in the README.
How do I add the server to Claude Desktop, Claude Code or Cursor?
Claude Code: claude mcp add --transport http fileconvert https://file-convert.online/api/mcp/v1/mcp --header "Authorization: Bearer fc_live_...". Cursor, Windsurf and most other clients take a JSON block with the url and a headers object. Claude Desktop only speaks to local processes for header-authenticated servers, so it uses the mcp-remote shim. All snippets are in the quickstart page and the client setup article.
Why do I have to restart my client after editing the config?
Most clients read their MCP configuration on startup and cache the tool list. After editing the JSON, restart the client (or reload the MCP servers panel where one exists) and check that the eight fileconvert tools appear.
Which formats and conversions are supported?
More than 110 formats in six categories: image, document, audio, video, archive and ebook. Conversions run within one category, for example docx to pdf or mov to mp4, but not png to docx. Call list_formats for the current catalogue, or ask the agent to list the formats for you.
Is there a file-size limit, and what happens if I exceed rate limits?
convert_file fetches files up to 200 MiB from a URL; upload_file accepts up to 25 MiB inline because base64 in a chat message is not the place for bigger payloads. Rate limits are per minute and depend on your plan; exceeding them returns 429 with a Retry-After header, and the MCP server turns that into an error that tells the agent to wait and retry.
Can I use it with ChatGPT?
ChatGPT's developer mode lets you register a remote MCP connector with a URL and a token. Point it at https://file-convert.online/api/mcp/v1/mcp and use your API key as the token. Support for custom connectors is evolving quickly on their side, so check their current documentation if the connector does not appear.
Can I use it from n8n, Zapier or other automation tools?
Yes. n8n has a native MCP Client Tool node that speaks Streamable HTTP with Bearer authentication; a full walkthrough is in the n8n article. Tools without MCP support can call the REST API directly with an HTTP node, following the OpenAPI description at https://file-convert.online/api/mcp/openapi.json.
Why am I getting 401 Unauthorized?
Almost always a header formatting problem: the value must be exactly Bearer, a space, then the key starting with fc_. Check for quotes that ended up inside the value, a trailing newline copied with the key, or a key created on the dev environment (fc_test_...) being used against production. A key that was revoked also returns 401.
Is my data secure, and how long are files kept?
Files are private to your account, transferred over HTTPS and deleted automatically. A converted result is downloadable for about an hour by default; you can extend a file's retention up to 14 days through the REST API if you need to. Keys are stored hashed, and the MCP server does not keep copies of your key or your files.
How much does it cost?
Each conversion costs credits: 1 for images, 2 for documents, audio, archives and ebooks, 5 for video. Free accounts receive 10 credits per day whenever their balance is empty. Paid plans with monthly allowances and higher limits are on file-convert.online/pricing. get_balance tells the agent how many credits are left.
Does the agent need to know numeric format ids?
No. Name formats by extension ("docx", "pdf", "webp"). The server resolves them; every extension currently maps to one category, and a format_type hint exists for the day that changes. Numeric ids still work for clients built against the first release.