api_error

HTTP 500, 503. Something went wrong on Flow’s side.

What it means

The failure is Flow’s, not your request’s. Nothing needs to change in what you sent.

Why it happens

A short outage or a restart (503 with retry_after).

How to fix it

Retry with the same Idempotency-Key after retry_after seconds (or with backoff); the key makes sure nothing is sent twice. If it keeps failing, quote error.request_id when you contact us.

for (let i = 0; i < 5; i++) {
  const res = await send(body, { idempotencyKey }); // same key every time
  if (res.status < 500) break;
  await sleep(2 ** i * 500);
}

Every error also carries hint, one sentence specific to your request, and doc_url, this page. Coding agents connected to Flow’s MCP server (https://api.flow.engineer/mcp) can call explain_error with the type to read this page.

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api_error

api_error

What it means

Why it happens

How to fix it

​api_error

​What it means

​Why it happens

​How to fix it

api_error

What it means

Why it happens

How to fix it