Rate Limiting
Last updated: February 16, 2026
Rate limiting is a technique that controls how many requests a client can make to a server within a defined time window. When a client exceeds the allowed threshold, subsequent requests are rejected, typically with an HTTP 429 (Too Many Requests) status code, until the window resets.
Why It Matters
AI assistant deployments face rate limits at multiple levels. Model providers like Anthropic and OpenAI enforce request-per-minute and token-per-minute limits on their APIs. Messaging platforms like Telegram, Discord, and Slack impose limits on how frequently bots can send messages. Your own gateway may also enforce rate limits to prevent abuse. Understanding rate limiting is essential for building a reliable assistant that handles high traffic gracefully without hitting walls that degrade the user experience.
How It Works
Rate limiting algorithms vary in sophistication. A fixed window counter resets at regular intervals, such as allowing 60 requests per minute. A sliding window smooths out bursts by tracking requests over a rolling time period. A token bucket algorithm allows short bursts up to a maximum capacity while refilling tokens at a steady rate. Most production systems use a combination of these approaches.
When your AI assistant hits a rate limit from a model provider, the API response includes headers like Retry-After or X-RateLimit-Reset indicating when to try again. Well-designed gateways implement automatic retry logic with exponential backoff, queuing requests and replaying them after the rate limit window expires rather than dropping them entirely.
In Practice
Monitor your rate limit usage through provider dashboards and API response headers. Implement request queuing in your gateway to handle burst traffic without losing messages. Consider caching frequent responses to reduce API calls. For multi-user deployments, implement per-user rate limits on your own gateway to prevent a single user from exhausting shared quotas. Set up alerts when usage approaches provider limits so you can upgrade plans before hitting hard caps.