OpenRouter 403: diagnose the error and check an API429 migration

An OpenRouter 403 does not automatically mean a regional block. It is a refusal that needs context: the endpoint, response format, safe error fields and the rules applying to the key and model. Stop repeatedly submitting the same request while the cause remains unresolved. If you are considering API429, diagnose the original refusal first, then separately check the new service's contract and your permission to use the selected model.

This guide was reviewed on 24 October 2026. It does not establish a country-wide restriction date, prove access for a particular account or report a completed generation test. It gives you a reproducible way to collect evidence, choose a next action and assess a migration without confusing catalog visibility with working inference.

Collect evidence without copying credentials

Record the UTC time, request method, hostname and path, model ID, HTTP status and Content-Type. Exclude query strings if they contain sensitive values. For a JSON response, inspect the shape of error, a numeric code and a short redacted message locally. A documented limit_source can help an administrator identify a budget rule. Never paste the whole response into a public issue: metadata may include submitted content or other sensitive details.

Keep one sanitized example and the relevant configuration version. Separate what you observed from what you suspect. “POST to this path returned 403 with JSON” is an observation; “every user in my country is blocked” needs independent evidence. Ask a teammate to check your summary for accidentally copied authorization headers before sending it to support. Share a request identifier only through an appropriate support channel.

Diagnosis matrix: status is the beginning

OpenRouter also documents a 402 for an in-flight spending budget with Retry-After; inspect that specific signal before choosing a bounded recovery policy.

The OpenRouter error reference and guardrail reference describe the supported error distinctions. A data-region constraint concerns where a request may be processed; the EU service page is not evidence of a general country/IP ban.

When retries help

A persistent refusal will not become a permission grant through repetition. Pause the affected job, retain its application operation ID and resolve the rule before resuming. If a separate transient failure warrants retrying, use a bounded policy with backoff, a maximum attempt count and a clear stop condition. Rate-limit handling should respect the service's documented signals. Never turn an unresolved 403 into an unlimited retry loop.

For an operation that might already have produced output, establish its outcome before resubmitting. A client timeout and a provider refusal are different observations. Keep recovery logic separate from access diagnosis so that an uncertain result does not accidentally create another paid generation.

What can be said about restriction dates?

The current OpenRouter Terms carry a revision date of 31 August 2026; section 5.7 addresses geographical model restrictions and applicable model terms. A terms revision date is not the start date of a restriction for your account.

A May feature recap, dated 1 June and updated 13 July 2026, describes enforcement of configured per-key IP allowlists. Its current text is evidence about that feature, not an immutable June snapshot or a Russia-wide block announcement. To establish a date for your own incident, obtain the actual account notice or a support statement identifying the model, account scope and effective date. Keep those boundaries when explaining an incident to customers.

Five migration checks for API429

1. Set the service address deliberately. OpenRouter's documented base URL is https://openrouter.ai/api/v1; API429's is https://gateway.api429.com/v1. Check the application's actual configuration, including overrides and environment precedence. Use a separate test configuration so rollback remains straightforward.
2. Use an API429 key. Store it locally in API429_API_KEY, outside application source and browser code. A credential from another service is not interchangeable. Confirm which server process receives the variable before diagnosing an apparent authentication failure.
3. Select the literal model ID returned for that key. Set API429_MODEL to the exact ID you intend to check. The public catalog helps with selection, while authenticated GET /v1/models checks the key's list. Similar spelling, provider prefixes or punctuation do not establish alias compatibility.
4. Review the features your application actually uses. Compare streaming, tools, structured output, image inputs and error handling against API429 documentation and the endpoint reference. An OpenAI-style endpoint does not establish every SDK, agent or native-feature capability. Keep unsupported assumptions out of the rollout checklist.
5. Run a representative paid trial only when you choose to. After reviewing the current pricing and applicable terms, use a small approved workload and inspect output, latency and the recorded charge. Expand gradually once your own acceptance criteria pass. The example below performs no inference and cannot complete this step for you.

The existing OpenRouter alternative page owns the detailed comparison and migration mapping. Use it to evaluate service differences without assuming a universal two-line transfer. Changing services does not establish permission to use a restricted model; confirm the terms that apply to your intended use.

Complete model-access check: one GET, no generation

Download api429-model-access-check.py. It uses Python's standard library. Set API429_API_KEY through your local secret-management workflow and set API429_MODEL to a candidate exact ID, then run python3 api429-model-access-check.py. Do not put a live key in a command argument, shared shell history or a screenshot.

The script stops before networking when either variable is missing. It makes one GET to a fixed HTTPS address, refuses redirects, bounds time and response size, validates JSON and checks exact membership. It prints no response bodies or credentials. A failure is a reason to inspect locally, not permission to retry indefinitely.

"""Check API429 model-list membership; never send a generation request."""
import json
import os
import socket
import urllib.error
import urllib.request

URL = "https://gateway.api429.com/v1/models"
MAX_BYTES = 1024 * 1024
TIMEOUT_SECONDS = 15


class NoRedirect(urllib.request.HTTPRedirectHandler):
    def redirect_request(self, req, fp, code, msg, headers, newurl):
        return None


def main():
    key = os.environ.get("API429_API_KEY", "").strip()
    model = os.environ.get("API429_MODEL", "").strip()
    if not key or not model:
        print("Set API429_API_KEY and API429_MODEL locally before running.")
        return 2
    if any(c in key for c in "\r\n"):
        print("Invalid credential format; check your local environment.")
        return 2
    request = urllib.request.Request(
        URL, headers={"Authorization": "Bearer " + key,
                      "Accept": "application/json"}, method="GET"
    )
    opener = urllib.request.build_opener(NoRedirect())
    try:
        with opener.open(request, timeout=TIMEOUT_SECONDS) as response:
            if response.status != 200:
                print("Unexpected HTTP status; stop and inspect locally.")
                return 1
            if response.headers.get_content_type() != "application/json":
                print("Expected JSON; stop and inspect locally.")
                return 1
            raw = response.read(MAX_BYTES + 1)
        if len(raw) > MAX_BYTES:
            print("Response exceeds the local size limit.")
            return 1
        payload = json.loads(raw)
        if (not isinstance(payload, dict) or "error" in payload
                or not isinstance(payload.get("data"), list)
                or not all(isinstance(row, dict)
                           and isinstance(row.get("id"), str)
                           for row in payload["data"])):
            print("Unexpected model-list structure; stop and inspect locally.")
            return 1
        if not any(row["id"] == model for row in payload["data"]):
            print("Exact model ID absent from this key's model list.")
            return 1
        print("Exact model ID found: model-list membership only; generation untested.")
        return 0
    except urllib.error.HTTPError as error:
        print("HTTP " + str(error.code) + "; no retry or redirect performed.")
    except (socket.timeout, TimeoutError):
        print("Request timed out; no automatic retry performed.")
    except urllib.error.URLError:
        print("Connection failed; no automatic retry performed.")
    except (ValueError, UnicodeError):
        print("Invalid JSON or local request format; stop and inspect locally.")
    return 1


if __name__ == "__main__":
    raise SystemExit(main())

A synthetic response fixture is available for offline inspection. Its model name is invented and is not a catalog claim. Success means only that the exact ID appeared in the model list returned for this key. It does not prove generation, feature support, future availability, pricing or an explanation for an OpenRouter refusal.

FAQ and next action

Can I identify a regional restriction from 403 alone?

No. Use the response evidence and the applicable account/model terms. If the message remains unclear, contact the relevant service's support with a sanitized reproduction. A successful website visit or a model name in a public catalog does not settle account access.

Does the access checker diagnose OpenRouter?

No. It calls API429's model-list endpoint only. Use it after you decide to assess API429; it cannot explain an earlier response from another service.

What should I do before changing production traffic?

Resolve uncertain request outcomes, document your chosen ID and required features, and keep a rollback configuration. Use the API429 FAQ for account and setup questions. Keep the original incident report separate from the migration acceptance record so that a successful new integration does not become an unsupported claim about the old failure.