bridgenode

Use BridgeNode for AI inference (LLM chat completions) without API keys or registration. Pay per request with Solana USDC via x402 (HTTP 402 payment flow). OpenAI-compatible endpoint, MCP server available. Use when an agent needs LLM inference and has a wallet with USDC but no provider API key, or when pay-per-request pricing is preferred over subscriptions.

BridgeNode is an AI inference bridge. Agents get an OpenAI-compatible endpoint and pay per request with Solana USDC via the x402 protocol. No API keys, no registration, no subscriptions. Transaction fees (SOL) are sponsored by BridgeNode — the agent only needs USDC in its wallet.

When to Use

• The agent needs LLM inference (chat completions) but has no provider API key.
• Pay-per-request is preferred over monthly subscriptions.
• The agent has a Solana wallet with USDC (or can receive it) and supports x402 payments.
• Deterministic, transparent per-request pricing is required.
• MCP-based agents that need a paid inference tool.

Endpoints

Endpoint	Purpose
https://bridgenode.cc/v1	OpenAI-compatible API base URL
https://bridgenode.cc/v1/models	Public model list + prices (no auth)
https://bridgenode.cc/v1/chat/completions	Chat completions (POST)
https://bridgenode.cc/mcp	MCP server (streamable-http)
https://bridgenode.cc/llms.txt	Full agent install map

Models & Pricing

Prices are in USDC per token (6 decimals). Always fetch live prices from GET /v1/models — they are the single source of truth and are generated from server config.

Model	Input / token	Output / token	Context window	Max output
deepseek-v4-flash	$0.00000020	$0.00000040	1,048,576	8,192
groq-llama-3.3-70b	$0.00000079	$0.00000099	131,072	32,768
deepseek-v4-pro	$0.00000085	$0.00000170	1,048,576	8,192

Pricing model: exact scheme — the agent pays for input tokens + max_tokens before processing. If the model generates fewer than max_tokens, the agent still pays for max_tokens (this is the business model, not a bug). Minimum charge per request: 2000 atomic units = $0.002 USDC.

Payment Flow (x402 V2, exact scheme)

1. Send the request without payment headers.
2. Server responds 402 Payment Required with a PAYMENT-REQUIRED header (base64 JSON): price, payTo address, USDC mint, memo, recent blockhash.
3. Agent constructs a partial transaction: USDC TransferChecked (amount = required) + Memo instruction, signs with its own wallet. Fee payer is NOT signed by the agent.
4. Agent retries the request with PAYMENT-SIGNATURE header (base64 JSON payload with the signed transaction).
5. Server verifies, settles on-chain (fee payer = BridgeNode, gasless for the agent), then processes the request.
6. Response is 200 with PAYMENT-RESPONSE header (settlement receipt).

Key details:

• Network: solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp (Solana mainnet)
• Asset: USDC EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v
• The agent must have an existing USDC ATA (associated token account) for the mint.
• The agent does not need SOL — BridgeNode sponsors transaction fees.
• Use the official x402 SDKs (@x402/svm, x402[svm]) or any x402-capable client — they handle the 402 → sign → retry flow automatically.

Quick Start (curl)

Step 1 — get payment requirements:

bash

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}'

Response: 402 with PAYMENT-REQUIRED header (amount, payTo, memo).

Step 2 — sign the partial transaction with an x402-capable client (e.g. x402curl, official SDK, or pay CLI) and retry:

bash

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}'

Response: 200 with the completion and PAYMENT-RESPONSE header.

Quick Start (Python, x402 SDK)

python

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

Use the official x402 Python client (x402[svm]) configured with the agent's Solana keypair; point it at https://bridgenode.cc/v1/chat/completions. Payment is automatic.

MCP Usage

• Server URL: https://bridgenode.cc/mcp (streamable-http)
• Tool: chat_completions (model, mode, messages, max_tokens)
• Payment: x402 handshake per tool call; prices are annotated in tools/list (x-x402) as an indication — always check the actual amount in the 402 response before signing.

Request Options

• model: explicit model ID from /v1/models (e.g. deepseek-v4-flash).
• mode: smart routing — auto (complexity-based tier), eco (cheapest), premium (best). If both model and mode are sent, model wins.
• max_tokens: request cap (default 4096, clamped to model max). Non-stream requests are capped at 4096 — use stream: true for longer generations.
• stream: SSE streaming supported (stream: true).

Errors

Status	Meaning
400	Bad request (unknown model, invalid body, oversized non-stream max_tokens)
402	Payment required — see PAYMENT-REQUIRED header
413	Request body too large (limit 2 MB)
429	Too many requests (queue limit)
503	Service busy — retry with backoff

All errors use the OpenAI error format: {"error": {"message": ..., "type": ..., "code": ...}}.

Notes

• Discovery: https://bridgenode.cc/.well-known/agent-card.json, /.well-known/mcp.json, /.well-known/ai-manifest.json
• Transaction fees are sponsored (gasless) — only USDC balance matters.
• Refunds: if the provider fails before any content is delivered, the payment is refunded automatically (reverse USDC transfer).