openrouter-common-errors

OpenRouter Common Errors

Overview

OpenRouter returns standard HTTP error codes plus OpenRouter-specific error codes in the response body. The most common: 401 (auth), 402 (credits), 429 (rate limit), 400 (bad request), and 5xx (upstream provider errors). Each error includes a code field and a human-readable message. This skill covers every common error, its root cause, and the exact fix.

Complete Error Reference

HTTP	Error Code	Cause	Fix
400	bad_request	Malformed request body	Validate messages array format; ensure model ID includes provider prefix
400	invalid_model	Model ID not found	Check model exists: curl -s https://openrouter.ai/api/v1/models | jq '.data[].id'
400	context_length_exceeded	Prompt + max_tokens > model limit	Reduce prompt size or use a larger-context model
400	invalid_tool_schema	Tool definition has unsupported types	Use basic JSON Schema types only (string, number, boolean, object, array)
401	invalid_api_key	Key malformed, revoked, or wrong	Regenerate at openrouter.ai/keys; key must start with sk-or-v1-
401	missing_api_key	No Authorization header	Add Authorization: Bearer sk-or-v1-... header
402	insufficient_credits	Credit balance is zero	Top up at openrouter.ai/credits
402	credit_limit_reached	Per-key credit limit hit	Increase key limit in dashboard or create new key
403	key_disabled	Key was disabled by admin	Re-enable in dashboard or create new key
408	request_timeout	Model took too long	Reduce max_tokens; use streaming; try faster model
429	rate_limit_exceeded	Too many requests per interval	SDK auto-retries; increase max_retries; use multiple keys
502	provider_error	Upstream provider returned error	Retry with backoff; try different provider via provider.order
503	model_unavailable	Model temporarily offline	Use fallback models; check status.openrouter.ai

Error Response Format

{
  "error": {
    "code": 401,
    "message": "Invalid API key. Please check your API key and try again.",
    "metadata": {
      "provider_name": "Anthropic",
      "raw": "..."
    }
  }
}

Diagnostic Script

#!/bin/bash
echo "=== OpenRouter Error Diagnostics ==="

# 1. Test authentication
echo -n "1. Auth: "
AUTH=$(curl -s -o /dev/null -w "%{http_code}" \
  https://openrouter.ai/api/v1/auth/key \
  -H "Authorization: Bearer $OPENROUTER_API_KEY")
[ "$AUTH" = "200" ] && echo "OK" || echo "FAIL (HTTP $AUTH)"

# 2. Check credit balance
echo -n "2. Credits: "
CREDITS=$(curl -s https://openrouter.ai/api/v1/auth/key \
  -H "Authorization: Bearer $OPENROUTER_API_KEY" | \
  jq -r '(.data.limit // 0) - .data.usage')
echo "\$$CREDITS remaining"

# 3. Test model availability
echo -n "3. Model: "
MODEL="openai/gpt-4o-mini"
EXISTS=$(curl -s https://openrouter.ai/api/v1/models | \
  jq --arg m "$MODEL" '[.data[] | select(.id == $m)] | length')
[ "$EXISTS" -gt 0 ] && echo "$MODEL available" || echo "$MODEL NOT FOUND"

# 4. Test a minimal request
echo -n "4. Request: "
RESP=$(curl -s -w "\n%{http_code}" \
  https://openrouter.ai/api/v1/chat/completions \
  -H "Authorization: Bearer $OPENROUTER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"openai/gpt-4o-mini","messages":[{"role":"user","content":"hi"}],"max_tokens":1}')
HTTP=$(echo "$RESP" | tail -1)
[ "$HTTP" = "200" ] && echo "OK" || echo "FAIL (HTTP $HTTP)"

Python Error Handler

import os
from openai import OpenAI, APIError, AuthenticationError, RateLimitError, BadRequestError, APITimeoutError

client = OpenAI(
    base_url="https://openrouter.ai/api/v1",
    api_key=os.environ["OPENROUTER_API_KEY"],
    max_retries=3,  # Auto-retry 429 and 5xx
    timeout=30.0,
    default_headers={"HTTP-Referer": "https://my-app.com", "X-Title": "my-app"},
)

def safe_completion(messages, model="openai/gpt-4o-mini", **kwargs):
    """Completion with categorized error handling."""
    try:
        return client.chat.completions.create(
            model=model, messages=messages, **kwargs
        )
    except AuthenticationError as e:
        # 401: Bad or missing API key
        raise SystemExit(f"AUTH ERROR: Check OPENROUTER_API_KEY. {e}")
    except BadRequestError as e:
        # 400: Bad model ID, invalid params, context too long
        if "context_length" in str(e):
            raise ValueError(f"Prompt too long for {model}. Trim or use larger-context model.")
        raise ValueError(f"Bad request: {e}")
    except RateLimitError:
        # 429: SDK already retried max_retries times
        raise RuntimeError("Rate limited after all retries. Wait or use more API keys.")
    except APITimeoutError:
        # Timeout: model too slow
        raise TimeoutError(f"Model {model} timed out. Try streaming or a faster model.")
    except APIError as e:
        # 402, 5xx, other
        if e.status_code == 402:
            raise RuntimeError("Insufficient credits. Top up at openrouter.ai/credits")
        raise RuntimeError(f"API error {e.status_code}: {e}")

Prevention Middleware

import requests

def validate_before_send(model: str, messages: list, max_tokens: int = 1024):
    """Pre-flight validation to catch common mistakes before API call."""
    errors = []

    # Check model exists
    models = requests.get("https://openrouter.ai/api/v1/models").json()["data"]
    model_ids = {m["id"] for m in models}
    if model not in model_ids:
        # Try to suggest correct ID
        prefix = model.split("/")[0] if "/" in model else ""
        suggestions = [m for m in model_ids if prefix and m.startswith(prefix)][:3]
        errors.append(f"Model '{model}' not found. Did you mean: {suggestions}")

    # Check messages format
    if not messages or not isinstance(messages, list):
        errors.append("messages must be a non-empty list")
    for msg in messages:
        if "role" not in msg or "content" not in msg:
            errors.append(f"Each message needs 'role' and 'content': {msg}")

    # Estimate context usage
    total_chars = sum(len(str(m.get("content", ""))) for m in messages)
    est_tokens = total_chars // 4
    model_info = next((m for m in models if m["id"] == model), None)
    if model_info:
        ctx_limit = model_info["context_length"]
        if est_tokens + max_tokens > ctx_limit:
            errors.append(f"Estimated {est_tokens} + {max_tokens} max_tokens > {ctx_limit} context limit")

    if errors:
        raise ValueError("Pre-flight validation failed:\n" + "\n".join(f"  - {e}" for e in errors))

Error Handling

Scenario	SDK Behavior	Your Action
429 rate limit	Auto-retries with backoff	Increase max_retries or add keys
5xx server error	Auto-retries with backoff	Increase max_retries; add fallback models
401 auth error	Fails immediately (no retry)	Fix API key and retry
400 bad request	Fails immediately (no retry)	Fix request parameters
402 no credits	Fails immediately (no retry)	Top up credits

Enterprise Considerations

• The OpenAI SDK handles 429 and 5xx retries automatically -- configure max_retries (default 2, recommend 3-5)
• Implement pre-flight validation to catch 400 errors before making API calls (saves money and time)
• Log error codes and rates to detect systematic issues (e.g., provider outages show as 502 spike)
• Build a status dashboard that checks both your error rates and status.openrouter.ai
• For 402 errors, implement credit balance monitoring with alerts at 20% remaining

References

• Examples | Errors
• Error Codes | Status