Quickstart

Step 1 — probe for the price#

Send the request without a payment header:

curl https://bridgenode.cc/v1/chat/completions \
  -H "Content-Type: application/json" \
  -d '{"model":"deepseek-v4-flash","messages":[{"role":"user","content":"hello"}],"max_tokens":100}'

The response is 402 Payment Required with a PAYMENT-REQUIRED header (base64 JSON) containing the exact price in USDC atomic units, the payTo Solana address, and a memo.

Step 2 — sign and retry#

Construct the partial transaction (USDC TransferChecked + memo instruction), sign it with the agent's own wallet, and retry with the signature attached:

curl https://bridgenode.cc/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "PAYMENT-SIGNATURE: <base64 payload>" \
  -d '{"model":"deepseek-v4-flash","messages":[{"role":"user","content":"hello"}],"max_tokens":100}'

The response is 200 with the completion and a PAYMENT-RESPONSE header confirming settlement.

In practice, an x402-capable client (the official x402 SDK, x402-proxy, or the pay CLI) automates both steps — it never returns a raw 402 to your application code, it handles the sign-and-retry internally.

Python (x402 SDK)#

# pip install "x402[svm]"
# The official x402 client handles the full 402 -> sign -> retry loop.

Configure the client with the agent's Solana keypair and point it at https://bridgenode.cc/v1/chat/completions. Payment is automatic.

Before you send a real request#

Check current prices and context limits first — they are the source of truth for what a given model costs and can handle:

curl https://bridgenode.cc/v1/models

This endpoint is public and requires no payment. See Models & Pricing for the current table.

Next#

• Payment Flow for the full protocol detail (network, asset, transaction shape)
• API Reference for the complete request and response schema
• Errors for what each status code means