OpenRouter 402 "Your account or API key has insufficient credits"

What does the error mean?

OpenRouter’s errors page describes a 402 as Your account or API key has insufficient credits. Add more credits and retry the request. The error type is payment_required.

The response body says which limit you hit. Look at error.metadata.limit_source.

limit_source	What happened	Retry?
openrouter_credits	Your balance can’t cover the request, or one request costs more than your whole in-flight budget	Not until you add credits or shrink the request
openrouter_in_flight_budget	Running and recently finished requests filled the in-flight budget	Yes, after the Retry-After header
openrouter_key_limit	The API key’s own credit limit is used up	Not until the key’s limit resets or goes up

Codes as listed on OpenRouter’s Limits page, checked November 5, 2026.

The in-flight case carries the message This request would exceed your available credits given your current in-flight requests. It’s the only 402 worth retrying unchanged.

How do you fix it?

1. Log error.metadata.limit_source and remedy_hint. Branch your code on the source and leave the hint for people reading logs.
2. For openrouter_credits, add credits at openrouter.ai/settings/credits until the balance is above zero.
3. If the balance is fine, lower max_tokens or trim the prompt. The up-front estimate counts input tokens plus every token max_tokens allows, or a fixed cap when max_tokens isn’t set.
4. For openrouter_in_flight_budget, wait for Retry-After and send it again. More credits also raise this budget, up to a ceiling.
5. For a key limit, raise the key’s credit limit in the dashboard or wait for its daily, weekly or monthly reset at midnight UTC. Some key and budget limits come back as a 403 with Key limit exceeded instead, so check both codes.

How do you keep it from coming back?

Turn on auto top-up on the credits page so the balance refills below a threshold. Then set the low balance alert. It’s on every plan, goes out by email and defaults to $100.

Put a credit limit on every key, especially ones an agent uses. OpenRouter recommends it, since a key with no limit can spend the whole balance, auto top-ups included.

You can also check GET /api/v1/key from your own monitoring to see limit_remaining before requests fail. ernd is a card for AI spend that earns 4% back, a good fit for whatever pays for the top-ups.