kaivaBRIDGE
GUIDE

How to convert an API into an MCP server

Updated

Give Kaiva Bridge your API's OpenAPI or Swagger spec. It creates one MCP tool for each operation and hosts the server for you, so there is no code to write and nothing to run. You switch on the tools your AI needs, publish, and add the server's address to Claude, ChatGPT, Cursor or any other MCP client.

Start freeRead the docs

Step by step

  1. Create a free accountSign up at app.kaiv.ai. No card is needed.
  2. Paste the spec linkChoose New server, then REST API, and paste the link to your OpenAPI (3.x) or Swagger (2.0) spec, in JSON or YAML. If the API needs a key, add it here: it is stored encrypted and never shown to the AI.
  3. Choose the toolsBridge reads the spec and lists one tool per operation, each marked as a read or a write. Servers are read-only by default: writes stay off until you switch them on.
  4. PublishClick Deploy server. Your MCP server is live at an address on api.kaiv.ai.
  5. Add it to your AI clientCopy the address from the Connect tab and add it to your client. Claude and ChatGPT sign in with your Kaiva account, so no key is needed.

The same from a terminal, with the open-source CLI:

Terminal
npx @kaiva/bridge login
npx @kaiva/bridge push my-api --openapi https://api.example.com/openapi.json --read-only
npx @kaiva/bridge install my-api --client claude-code

Read-only by default. Writes when you decide.

Your server starts read-only. Writes are optional: switch on the ones you want when you are ready, after checking what they do.

From inside Claude

Kaiva Bridge is in Claude's connector directory. Connect it, then ask Claude: "Turn https://api.example.com/openapi.json into an MCP server. Which tools do I need?" Claude creates the server, lists its tools and recommends the ones for your task. You publish it in the console with one click.

What you need

A link to the API's OpenAPI or Swagger document, or the file itself (you can paste or upload it). If you only have a documentation page, paste its link: Bridge follows a Swagger UI or docs page to the spec it points to, and reads GitHub, GitLab, Bitbucket, SwaggerHub and Dropbox links as the file they show.

Free includes 3 MCP servers, 200,000 tool calls a month and 200 pages of documents, with no card.

Other ways to do it

  • Run an open-source generator yourselfSeveral open-source projects generate an MCP server from an OpenAPI spec, including FastMCP's OpenAPI support. You host, update and secure the server, and store the API credentials, yourself.
  • Use the vendor's own MCP serverIf the company behind the API publishes an official MCP server, use it. Bridge can also put a remote MCP server behind one address with your other servers.
  • Write one with an MCP SDKThe official TypeScript and Python SDKs let you write each tool by hand. That gives full control, at the cost of writing and maintaining the code.

Questions

Do I need to write code?
No. Bridge generates the tools from the spec and hosts the server. You choose which tools to switch on.
Does it work with Swagger 2.0?
Yes. OpenAPI 3.x and Swagger 2.0 both work, in JSON or YAML.
What if my API needs an API key?
Add it when you create the server: a bearer token, basic auth or a custom header such as X-API-Key. It is encrypted, added to each call on the server side and never sent to the AI client.
Can the AI change data through my API?
Only if you switch writes on. Servers are read-only by default, and writes are optional.
Is it free?
Free includes 3 MCP servers, 200,000 tool calls a month and 200 pages of documents, with no card.

Related guides