Error Handling

BlockRun uses standard HTTP status codes and returns detailed error information.

HTTP Status Codes

Error Response Format

Gateway errors use the OpenAI envelope, with message and code mirrored at the top level for older clients. debug carries the upstream text when there is one, redacted: credentials, URLs and any routing infrastructure we do not sell under its own name are removed before the response is sent. The status code and the upstream's own description of the fault survive, so debug stays useful for a bug report — it is just not a verbatim copy.

{
  "error": {
    "message": "Invalid request parameter — Message @bc1max on Telegram for help.",
    "type": "invalid_request_error",
    "code": "INVALID_PARAMETER",
    "param": null
  },
  "message": "Message @bc1max on Telegram for help.",
  "code": "INVALID_PARAMETER",
  "debug": "<upstream error text, redacted>"
}

error.type is one of invalid_request_error, rate_limit_error, api_error, payment_required. The Anthropic-compatible /v1/messages endpoint answers in Anthropic's {"type":"error","error":{"type","message"}} shape and /v1/responses in OpenAI's {"error":{"message","type","param","code"}} shape instead.

Error codes

Common Errors

400 - Invalid Request

{
  "error": {"message": "Invalid request body", "type": "invalid_request_error", "code": "INVALID_REQUEST_BODY", "param": null},
  "message": "Invalid request body",
  "code": "INVALID_REQUEST_BODY",
  "details": [
    {"path": ["model"], "message": "Required"}
  ]
}

An unknown model is a plain-string error that suggests live IDs:

{"error": "Unknown model: openai/gpt-4. Try one of: openai/gpt-5.6-sol, …. Full list: GET /v1/models"}

Causes:

• Missing required fields (model, messages)
• Invalid model ID
• Malformed JSON
• A parameter the upstream model rejects (INVALID_PARAMETER) — the gateway surfaces these as 400, not 500

402 - Payment Required

{
  "x402Version": 2,
  "accepts": [{"scheme": "exact", "network": "eip155:8453", "amount": "25685", "asset": "0x8335…", "payTo": "0x…", "maxTimeoutSeconds": 300}],
  "error": "Payment Required",
  "message": "This endpoint requires x402 payment",
  "price": {"amount": "0.025685", "currency": "USD"},
  "paymentInfo": {"network": "base", "asset": "USDC", "x402Version": 2}
}

The signed requirements travel in the X-Payment-Required / PAYMENT-REQUIRED headers (and WWW-Authenticate: X402 requirements="…"), and — since 2026-08-30 — are mirrored at the top level of the JSON body too (x402Version, accepts), byte-identical to the decoded header. This is for v1-era x402 clients (early x402-fetch/x402-axios and third-party wrappers) that only parse the body and silently fail to auto-pay when there's no top-level accepts. price.amount equals the signed amount, including the flat $0.001 transaction fee.

402 - Payment Rejected

A PAYMENT-SIGNATURE that fails verification is answered with 402 and a machine-readable code (since 2026-08-26, on every BlockRun-native paid endpoint):

{
  "error": "Payment verification failed",
  "code": "PAYMENT_UNFUNDED",
  "message": "The payment authorization could not be executed on-chain. The usual cause is an insufficient USDC balance on Base for the quoted amount — …",
  "debug": "<facilitator reason>",
  "payer": "0x…"
}

Verification always runs before settlement, so none of these charged you. On the Solana gateway PAYMENT_VERIFICATION_UNAVAILABLE means the facilitator was unreachable — retry the same signed payment.

429 - Rate Limited

{
  "error": {"message": "Rate limited — … retry after 60s, or fail over to a same-tier model on a different provider.", "type": "rate_limit_error", "code": "RATE_LIMITED", "param": null},
  "code": "RATE_LIMITED",
  "source": "openai",
  "retry_after_seconds": 60
}

Headers: Retry-After: 60, X-RateLimit-Source: <model family>. Free models add FREE_TIER_RATE_LIMITED with X-RateLimit-Limit / X-RateLimit-Remaining / X-RateLimit-Reset. See Rate Limits.

503 - Model Unavailable

{
  "error": {"message": "Model unavailable — Message @bc1max on Telegram for help.", "type": "api_error", "code": "MODEL_UNAVAILABLE", "param": null},
  "code": "MODEL_UNAVAILABLE",
  "debug": "<upstream text>"
}

Retry, or fail over to a same-tier model from a different family. Not settled.

500 - Server Error

{
  "error": {"message": "Unexpected error — Message @bc1max on Telegram for help.", "type": "api_error", "code": "INTERNAL_ERROR", "param": null},
  "message": "Message @bc1max on Telegram for help.",
  "code": "INTERNAL_ERROR",
  "debug": "<error text>"
}

Causes:

• Unclassified upstream error
• Temporary service issue

Settlement happens only after a successful upstream response, so a 500/503/504 never charges you.

SDK Error Classes

Troubleshooting

"Payment verification failed"

1. Read the code: PAYMENT_UNFUNDED → top up USDC on Base (or on Solana for sol.blockrun.ai)
2. PAYMENT_REPLAY → your client reused a nonce; sign a fresh authorization per request
3. PAYMENT_BLOCKHASH_STALE → re-sign; the Solana blockhash expired between signing and sending
4. PAYMENT_INVALID → confirm you signed the exact accepts[0] entry from the header (network, asset, amount, payTo) and that the wallet is on the right network

"Unknown model"

1. Check the model ID matches exactly (e.g., openai/gpt-5.5)
2. See available models for valid IDs

"Timeout"

1. Increase the timeout in client options
2. Try a faster model (e.g., gpt-5.4-mini instead of a -pro reasoning tier), or lower max_tokens — the gateway's own upstream timeout is 120s per call

"Network error"

1. Check your internet connection
2. Verify blockrun.ai/api is accessible

What's next?