Rate limiting

Avoid being overwhelmed. Fastly's network can handle hundreds of terabits of traffic per second, so whether it's managing a queue for a product or ticket release, preventing abusive traffic from bots, or billing API customers based on their usage, rate limiting at the edge is a great use of Fastly.

Virtual waiting room

Fastly features

Our dedicated Edge Rate Limiting product provides ratecounter and penaltybox primitives to VCL and Compute services. Real time logging allows data from the edge to be streamed to a destination of your choice, which is often useful for counting specific types of request.

Granular counters are also included with Advanced Rate Limiting rules in our Next-Gen WAF.

HINT: Compute customers can find equivalent functions in Compute SDKs.

Ideas and typical uses

Typically, rate limiting requests at the edge broadly falls into one of three use cases:

  • Abuse prevention: stopping abusive bots that may be badly configured, malfunctioning or intentionally attempting to bring down your site in a denial-of-service attack. This is a great use of Edge Rate Limiting.
  • Metering: Accurately measuring activity for billing or subscription purposes, with a cutoff when a prescribed volume is reached. Consider using Real time logging in combination with an aggregation or business intelligence tool outside of Fastly to receive and process the data.
  • Queueing: Flattening the curve of traffic surges caused by product releases or sudden major publicity. The Compute platform, combined with a state store capable of atomic incrementing counters is a good way to create queueing solutions at the edge, or alternatively consider a stateless waiting room solution if strict queue order is not important.


The following demos, tutorials, starter kits, and code examples are relevant to this use case. Try them out!


Step by step instructions. Build and learn.

Rate limitingUse ratecounters and penalty boxes to stop high-volume automated attacks against your website.
Stateful waiting roomYou have regular large volumes of traffic and need to limit the rate at which users can start new sessions. Once a user has been allowed in, they should retain access.

Starter kits

Template Compute applications you can use to bootstrap your project.

Queuing / Waiting room (JS)Park your users in a virtual queue to reduce the demand on your origins during peak times.

Code examples

Snippets of code ready to copy and paste.

Bot detection using ratecounterRate counters are normally used for detecting high volume DoS-style attacks, but you can also use them to measure lower rates, to ensure that navigation between pages is happening at human speed.
Cache '429' rate-limiter responses per IPIf a backend returns a 429, cache it for the requesting IP but continue to allow other clients to use origin.
Flatten the curve of major traffic spikes with a waiting roomA totally stateless solution to hold back new users for a minimum waiting period to smooth out spikes in traffic.
Rate limit requestsUse ratecounters and penalty boxes to stop high-volume automated attacks against your website.
Slowing down responses (tarpit)Force a response to be delivered very slowly to reduce the rate at which an attacker can send requests.
Throttling per country over configurable time periodsAdjust the maximum TCP socket pacing for connections at peak times of day in busy regions.

Blogs and articles