corelayer0 — Connect any API to any LLM in 30 seconds<br>Code Mode is now available — two fixed tools to call any API without flooding your LLM context.<br>FREN<br>Create my MCP server →

Any API.<br>Connected to any LLM.<br>In 30 seconds.<br>Today, making an LLM talk to your API means writing an MCP server — one per API. We automate that: upload your OpenAPI spec, get a hosted MCP URL that works instantly in Claude, ChatGPT, Mistral, or any compatible client.<br>EU-hosted - GDPR-native - Your credentials never touch a US cloud<br>Try with my spec →Watch a demoNo card required. 100 endpoints · 5,000 calls/month.

openapi.json

1 Spec in<br>"openapi": "3.0.3",<br>"info": {<br>"title": "corelayer0 sample library",<br>"version": "1.0.0"<br>},<br>"servers": [<br>{ "url": "https://toplib.tld/api/v1" }<br>],<br>"paths": {<br>"/books": {<br>"get": {<br>"operationId": "listBooks",<br>"summary": "List books with optional filters",<br>"parameters": [<br>{ "name": "genre", "in": "query", "schema": { "type": "string" } },<br>{ "name": "author", "in": "query", "schema": { "type": "string" } },<br>{ "name": "q", "in": "query", "schema": { "type": "string" } }<br>},<br>"post": { "operationId": "createBook",<br>"summary": "Create a book (simulated)" }<br>},<br>"/books/random": {<br>"get": { "operationId": "getRandomBook",<br>"summary": "Return one book chosen at random" }<br>},<br>"/books/{id}": {<br>"get": { "operationId": "getBook",<br>"summary": "Get a book by numeric id" },<br>"patch": { "operationId": "patchBook",<br>"summary": "Patch a book by id (simulated)" },<br>"delete": { "operationId": "deleteBook",<br>"summary": "Delete a book by id (simulated)" }<br>},<br>"/inventory": {<br>"get": { "operationId": "getInventory",<br>"summary": "List stock levels and prices for all books" }<br>},<br>"/orders": {<br>"post": { "operationId": "createOrder",<br>"summary": "Place a book order (simulated)" }<br>},<br>"/orders/{order_id}": {<br>"get": { "operationId": "getOrder",<br>"summary": "Get the status of an existing order" }<br>2 Generated MCP server<br>GETlist_booksready<br>GETget_random_bookready<br>GETget_bookready<br>PATCHpatch_bookready<br>DELETEdelete_bookready<br>POSTcreate_bookready<br>GETget_inventoryready<br>+ 2 more

9 tools generated·—·v0.1Regenerate ↻

How it works<br>Three steps. Zero code.

You keep your API. We translate OpenAPI → MCP in real time — auth, schemas and errors preserved.

01Import your OpenAPI<br>JSON or YAML, or a public HTTPS URL. OpenAPI 3.x and Swagger 2.0 — Postman collections coming soon.<br>library-openapi.json9 endpoints3.1.0

02We generate the MCP server<br>Every endpoint becomes a properly typed MCP tool. Auth is injected server-side, automatically.<br>// generated tool<br>tool list_books {<br>genre?: string<br>author?: string<br>q?: string<br>} // from GET /books

03Connect your LLM<br>Paste the MCP URL into your LLM (Claude, ChatGPT, Mistral, or any compatible client). Instant — and the URL stays stable when you update your spec.<br>CClaudeconnected<br>GChatGPTconnected<br>MMistralconnected

Before / after<br>One week of dev vs. thirty seconds.

The spec already exists. MCP boilerplate is repetitive and costly to maintain. Let us generate it — cleanly, on every release.

WITHOUT corelayer0<br>You write the MCP server by hand. Per API. Per version.<br>Redeclare every endpoint in TypeScript or Python<br>Rewire auth, types, pagination, error handling<br>Maintain it manually on every spec change<br>Deploy, monitor, manage secrets yourself<br>~1 week per API · ×N APIs

WITH corelayer0<br>You provide the spec. You get the MCP URL. Done.<br>Automatic generation from OpenAPI 3.x<br>Auth injected automatically<br>Update your spec anytime — stable MCP URL, connected LLMs don't break<br>EU-hosted (France 🇫🇷 - OVHcloud)<br>30 sec · any API

Under the hood<br>Everything you'll never have to write again.

Zero MCP infrastructure to maintain. Your API stays yours — auth, data, logic.

⌘Auth injected automatically<br>Credentials never reach the LLM — they're injected server-side on every outbound call. No token, static Bearer, or OAuth2 Client Credentials — your choice.<br>No tokenpublic APIsavailable<br>API key / Bearerheader injectionavailable<br>OAuth2 Client Credentialsmachine-to-machineavailable

↻Spec always in sync<br>Paste your JSON or point to an HTTPS URL. Update your spec anytime — the MCP URL stays stable, your connected LLMs don't disconnect.<br>30s<br>to generate an MCP server

stable<br>URL across spec updates

endpoints supported

⊞Endpoint filtering<br>Enable or disable each endpoint from the dashboard. Expose exactly what your LLM needs — nothing more.

◐Native OAuth 2.1 per project<br>Each MCP server is its own Authorization Server. MCP clients connect without pre-shared tokens — PKCE S256, dynamic client registration, automatic rotation.

⌂EU sovereignty by design<br>Hosted on OVHcloud (France 🇫🇷, EU), secrets encrypted under an EU-controlled KMS. Your data and credentials never leave the European Union — and never fall under the US CLOUD Act. GDPR-native, no transatlantic data transfer to assess.

⇄A gateway between your APIs and every LLM<br>We speak MCP on the LLM side, plain HTTP/REST on your side. No agent to deploy, no SDK to integrate. Your LLM clients see tools;...