Network services
Customize your content delivery.
Full-Site Delivery
Streaming Delivery
TLS
Image Optimizer
Security
Protect your services and applications.
Next-Gen WAF
Edge Rate Limiting
Access Control Lists
Compute
Experiment with Fastly's edge computing platform.
Compute services
Testing and debugging
Edge Data Storage
Quick start
Go from zero to Fastly with these step-by-step guides and tutorials.
Delivery getting started guide
Compute getting started guide
Building blocks
Start with the basics and learn how Fastly lets you take advantage of the modern internet.
Basics
Core concepts
Web interface guides
See all guides

Log in Try Fastly free

client.class.checker

BOOL, read-only.

Available inall subroutines.

The client is an automated checker (e.g., W3C Validator).