How it works

One gateway. Paid per call. Rated by measurement.

Probegrade sits between your agents and the tools they call. It handles payment, metering and trust, so your team doesn't have to.

Probegrade sources providers

We find tools and APIs worth calling, agree terms with each provider and list them with a clear per-call price.

Your agent calls the gateway

One endpoint, one account. Agents can discover sources through the MCP server or call them over HTTP.

x402 handles payment

If a call costs money, the gateway replies HTTP 402 with the price. The agent signs a payment and retries. No card forms, no API key swaps.

Probes keep everyone honest

Automated probes call every listed source on a schedule and record uptime, latency, schema validity, price and freshness.

You see every call

Usage logs show what each agent called, what it paid and how the source performed.

# 1. Agent calls a tool through the gateway GET /v1/call/weather.forecast?lat=36.16&lon=-86.78 # 2. Gateway answers with the price HTTP/1.1 402 Payment Required PAYMENT-REQUIRED: {scheme:"upto", network:"eip155:8453", maxAmount:"…"} # 3. Agent retries with a signed payment, gets data PAYMENT-SIGNATURE: eyJ4NDAyVmVyc2lvbiI6Mi… HTTP/1.1 200 OK

x402 payments

Built on the open x402 standard.

x402 revives HTTP 402 Payment Required so software can pay for a request inside the request.

x402 v2

Uses the PAYMENT-REQUIRED and PAYMENT-SIGNATURE headers with CAIP-2 network IDs: Base (eip155:8453) and Base Sepolia for testing.

Backward compatible

Older agents that send the v1 X-PAYMENT header still work. Upgrade on your schedule.

Exact or upto

“Exact” charges a fixed price. “Upto” lets the agent approve a cap and pays only the metered amount, never more.

MCP server

Works with the agent tools you already use.

The Probegrade MCP server runs locally over stdio or remotely over Streamable HTTP. Agents can look up scores, compare sources and call tools.

# Remote (Streamable HTTP) POST https://POST https://api.probegrade.com/mcplt;gateway-hostPOST https://api.probegrade.com/mcpgt;/mcp # Local (stdio) in an MCP client config { "mcpServers": { "probegrade": { "command": "python", "args": ["mcp_server.py"] } } }

Endpoint details are shared with early access accounts.