> ## Documentation Index
> Fetch the complete documentation index at: https://docs.square1.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Rate limits

> Every ceiling between your client and the model, and how each one answers

Independent of [token quotas](/concepts/quotas), several request-rate
ceilings apply. From the edge inward:

## 1. Edge IP limit

The edge in front of `inference.square1.dev` rate-limits by client IP
(on the order of 30 requests/minute with a small burst allowance).
Exceeding it returns a plain edge error **before** the request reaches
the API — you will not get the JSON error envelope.

This exists to absorb runaway clients; normal chat usage doesn't
approach it.

## 2. Per-model RPM (yours)

Each model has a per-account requests-per-minute limit — read it from
`rate_limit_rpm` in `GET /v1/models` and from the
`x-ratelimit-*-requests` response headers.

* Only **served** requests count toward the window; requests rejected by
  quota or validation don't burn RPM.
* Exceeding it → `429 rate_limited`.

## 3. Account burst cooldown

A safety net across **all** models: if one account fires too many
attempts (any status) in a short window, every request from that account
is rejected for a cooldown period.

* Trip → `429 abuse_cooldown` with `resets_at` in the envelope.
* The most common cause is an aggressive auto-retry loop hammering a
  failing request. Back off on errors instead of retrying in a tight
  loop — retrying into a cooldown only extends the outage on your side.

## 4. Model concurrency

Each model has a cap on concurrent in-flight requests across all users.
When it saturates you get **HTTP 529** `model_overloaded` — a global
"this model is busy" signal, not something you caused. Retry after a few
seconds.

## Retry guidance

| Signal                                       | Retry?     | How                                                            |
| -------------------------------------------- | ---------- | -------------------------------------------------------------- |
| `429 rate_limited`                           | Yes        | Wait for the RPM window (`x-ratelimit-reset-requests` seconds) |
| `429 abuse_cooldown`                         | Yes        | Wait until `resets_at` — retrying earlier is pointless         |
| `429 session_exhausted` / `weekly_exhausted` | Yes        | Wait until `resets_at`                                         |
| `429 model_quota_exceeded`                   | Yes        | Try another model, or wait for the 09:00 KST reset             |
| `529 model_overloaded`                       | Yes        | Short exponential backoff (seconds)                            |
| `500 upstream_error`                         | Cautiously | One or two retries with backoff; then surface the error        |
| `503 maintenance` / `server_draining`        | Yes        | Tens of seconds                                                |
| Any `400` / `401` / `403`                    | No         | Fix the request, key, or account first                         |