Configuration

These articles describe configuration settings and changes you can make to your cache settings when setting up Fastly services.

• Caching configuration best practices
• Controlling caching
• Enabling API caching
• Implementing API cache control
• Overriding caching defaults based on a backend response
• Preventing cache poisoning via HTTP X-headers
• Segmented Caching

These articles describe conditions and how to use them in VCL and the Fastly web interface.

• About conditions
• Troubleshooting conditions
• Using conditions

These articles describe how to create your own VCL files with specialized configurations.

• About VCL Snippets
• Accept-Language header VCL features
• Authenticating before returning a request
• Basic authentication
• Custom responses that don't hit origin servers
• Enabling URL token validation
• Guide to VCL
• Isolating header values without regular expressions
• Manipulating the cache key
• Response Cookie handling
• Support for the Edge-Control header
• Understanding the different PASS action behaviors
• Uploading custom VCL
• Using dynamic VCL Snippets
• Using regular VCL Snippets
• VCL regular expression cheat sheet

These articles describe how to move rapid key/value pair decision logic to the edge using dictionaries.

• About dictionaries
• Working with dictionaries using the web interface

These articles describe configuration settings and changes you can make to your domains and origins when setting up Fastly services.

• Changing origins based on user location
• Failover configuration
• IPv6 support
• Maintaining separate HTTP and HTTPS requests to origin servers
• Routing assets to different origins
• Setting up redundant origin servers
• Specifying an override host
• Using Fastly with apex domains
• Using Fastly's global POP network

These articles describe configuration settings and changes you can make to your headers when setting up Fastly services.

• Adding or modifying headers on HTTP requests and responses
• Enabling cross-origin resource sharing (CORS)
• Removing headers from backend response
• Setting Content Type based on file extension
• Understanding the X-Timer header

These articles provide basic instructions for and examples of setting up and beginning to use the Fastly Image Optimizer.

• About Fastly Image Optimizer

These articles provide information about distributing requests across multiple servers to optimize resource use and avoid overloading any single resource.

• About Dynamic Servers
• Creating and using pools with Dynamic Servers
• Creating and using server entries with Dynamic Servers
• Load-balancing configuration

These articles describe how to adjust the performance of Fastly's services beyond standard configuration methods.

• Enabling automatic gzipping
• Enabling HTTP/3 for Fastly services
• Failure modes with large files
• HTTP/2 server push
• Making query strings agnostic
• Precision Path
• Serving stale content
• Streaming Miss

These articles describe how to purge cache.

• Authenticating URL purge requests via API
• Purging a URL via the web interface
• Purging all content via the web interface
• Purging via API
• Purging with surrogate keys
• Setting Surrogate-Key headers for Amazon S3 origins
• Soft purges
• Wildcard purges
• Working with surrogate keys

These articles describe configuration settings and changes you can make to requests when working with Fastly services.

• Checking multiple backends for a single request
• Conditionally changing a URL
• How request settings are applied
• Manipulating the X-Forwarded-For header

These articles describe configuration settings and changes you can make to your response settings when setting up Fastly services.

• Creating and customizing a robots.txt file
• Creating error pages with custom responses
• Responses tutorial

These articles describe setup and configuration guidelines for setting up live stream delivery or video on-demand.

• Adaptive bitrate playback URL guidelines
• Collecting OTFP metrics
• Configuration guidelines for live streaming