MCP-ready · MVP

Turn any API into an MCP server for AI agents

ToolRelay wraps your existing APIs into secure, logged, rate-limited MCP-ready tools — with API keys, usage limits, and Stripe billing built in.

Create your first MCP tool See MCP integration

No credit card required. 1 tool free forever.

Everything you need to ship a paid MCP tool

API to MCP in minutes

Paste an endpoint URL, pick public or private, and ToolRelay generates an MCP-style tool surface plus a raw HTTP proxy. No agent SDK to wire up.

Secure by default

Private tools require a per-tool x-toolrelay-key. SSRF guard rejects internal hosts, every call has a 25s timeout, and auth header values are stored server-side and never echoed.

Built for monetization

Free vs Pro plan limits enforced server-side, Stripe Checkout + webhook for billing, and usage logs you can audit per tool and per month.

Works with agents

Plug the MCP endpoint URL into Claude, an MCP client, or any automation workflow. Public tools are open; private tools accept the API key as a header.

From endpoint to MCP tool in three steps

You bring the API. ToolRelay handles the agent surface, metering, and billing.

Add your API

Paste an endpoint, method, and optional upstream auth header. Define inputs and a sample response.

Get an MCP-ready tool

ToolRelay generates /api/mcp/your-slug for agents and /api/run/your-slug as a raw HTTP proxy.

Track usage and bill

Every call is logged with status and latency. Plan limits enforce Free vs Pro. Stripe handles subscriptions.

Call it like an MCP tool

Every tool exposes an MCP-ready JSON endpoint. Agents POST { arguments: { … } } and get back the upstream response wrapped in a content array.

curl -X POST 'https://www.toolrelay.online/api/mcp/your-slug' \
  -H 'Content-Type: application/json' \
  -H 'x-toolrelay-key: trk_…' \
  -d '{"arguments":{"message":"hello from an agent"}}'

Read the MCP integration guide →

Simple pricing

Start free with a public MCP tool. Upgrade when you need private tools or more runs.

Free

$0/mo

• 1 public MCP-ready tool
• 100 runs / month
• Public tool page + MCP endpoint
• Basic usage logs

Start free

Pro

Frequently asked

What does "MCP-ready" actually mean here?+

Every ToolRelay tool exposes a /api/mcp/[slug] endpoint. GET returns the tool metadata (name, description, schemas, security model). POST accepts { "arguments": { … } } and forwards to your upstream, returning the response wrapped in MCP-style { content: [{ type: "text", text }] }. Full MCP transport support (SSE/stdio) is on the roadmap.

How is a private MCP tool secured?+

Private tools require a per-tool key (prefix trk_…) sent as the x-toolrelay-key header. Missing/invalid keys return a 401 with a structured error code, and unauthorized attempts are written to your usage_logs.

Where is the upstream auth header stored?+

Server-side in Postgres (encrypted at rest by Supabase). The value is forwarded to your upstream on every call but is never displayed in the dashboard or logged in usage_logs after save.

What counts as a run?+

Every call to /api/mcp/[slug] or /api/run/[slug] counts as one run, success or failure. Plan caps reset on the first of each month UTC.

Ship your first MCP tool tonight.

Wrap any API endpoint into a secure, logged, billable tool that AI agents can call. In under five minutes.

Create your first MCP tool See MCP integration