Your first paid call

Four steps to a paid call. You do not install anything.

1. 1 Sign in with Google, GitHub or Apple and choose the developer role.
2. 2 Add funds. There is no auto-top-up — the balance you add is the ceiling on what anything can spend.
3. 3 Mint a key. It is shown once. Give it a 24-hour cap if you want one.
4. 4 Call a tool.

Your first call#

curl -s https://api.nexus402.dev/v1/mcp \
  -H "X-Nexus-Api-Key: nx_dev_..." \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "tools/call",
    "params": {
      "name": "acme/weather/forecast",
      "arguments": { "city": "Lisbon" }
    }
  }'

That is standard MCP JSON-RPC. The only thing that is ours is the header.

Finding tools to call#

The catalog is public and needs no key, so you can browse before you fund anything:

# Every published tool, with its price and description
curl -s https://api.nexus402.dev/v1/tools

# One tool's input schema and example
curl -s https://api.nexus402.dev/v1/tools/acme/weather/forecast

What to read next#

• Using an MCP client — point the client you already have at the gateway.
• Keys and caps — bound what any one key can spend in a day.
• Error codes — what each refusal means and whether you were charged.