# Limits

> Rate limits, request sizes and timeouts.

Source: https://www.lyber.ai/docs/api/limits/ · Markdown: https://www.lyber.ai/docs/md/api/limits.md

## Rate limits

| Scope | Limit |
| --- | --- |
| Requests per account | 60 per minute |
| Concurrent requests per account | 4 |
| Concurrent requests per model | 1, shared by all customers |

Each model serves one request at a time and keeps no queue. A request that arrives while the model is busy gets `429` with `x-lyber-admission: not-admitted` and `Retry-After: 5`. Nothing was started or charged, so wait and send it again.

## Request size

| Limit | Value |
| --- | --- |
| Request body | 16 MiB |
| `messages` and `tools` as JSON | 8 MiB |
| Messages per request | 4,096 |
| Tools per request | 32 |
| Context | 1,048,576 tokens, input and output together |
| Output | 32,768 tokens (MiniMax M3.1 Flash), 262,144 tokens (DeepSeek V4.1 Flash 1017) |

## Timeouts

| Limit | Value |
| --- | --- |
| Uploading the request body | 15 seconds |
| Generating the response | 180 seconds |

A request that runs past its time limit returns `504 upstream_timeout`, or ends a stream without `[DONE]`. Very long outputs can take longer than that; set `max_tokens` to what you need.