Fastly’s Full-Site Delivery

Fastly’s Full-Site Delivery allows you to speed up websites and mobile applications by pushing content closer to users, providing improved and secure experiences across the world. Full-Site Delivery includes the following features.

Content serving, caching, and control

Full-Site Delivery uses Fastly’s global content delivery capabilities to cache and accelerate the delivery of your HTTP-based file content such as video, images, CSS, JavaScript files, as well as HTML and API responses. Specifically:

  • HTTP header controls. Full-Site Delivery obeys standard HTTP caching headers and support forwarding, adding, removing, and modifying the HTTP headers we receive from your origin servers and send to end users, allowing you to send one set of instructions to your Fastly services and another set of instructions to downstream caches, proxies or browsers.

  • Time to Live controls. Content expiration is controlled via Time to Live (TTL) settings you configure that work as timers on your cached content. You have the option of configuring a global default TTL to control cached content which, when set, will cache objects in a consistent manner even if you have multiple origins or server applications with inconsistent TTL settings.

  • Request collapsing. When your content expires, the fetch and refresh process from your origin may take one second or more. During that time, your Full-Site Delivery may receive dozens or hundreds of end-user requests for that content. Fastly's request collapsing feature groups those requests and fulfills them together when it receives the refreshed content from your origin. Request collapsing decreases load on your origin servers by keeping your Fastly services from sending duplicate requests for the same expired content to them. Request collapsing is enabled by default.

  • Grace mode (Serving stale content). If your origin servers become unavailable for any reason, grace mode can instruct your Fastly services to continue to serve stale or expired (but likely still valid) content to end users for a set amount of time. This allows you some extra time to return your unavailable servers to normal operations while still serving content instead of error messages to end users. Grace mode is not configured by default. To enable it, you must specifically configure your services to serve stale content.

  • Compression. To help you speed up information transmission, we allow you to compress static content during transmission thereby making it available to your customers more quickly. To enable static or dynamic content compression, you must either enable automatic compression or set up an advanced compression policy.

  • Purging. For dynamic or event-based content that doesn’t lend itself to predetermined TTL-based content expiration, you can proactively remove or invalidate your content within milliseconds with Fastly's purging features. We limit purging to an average of 100K purges per hour per customer account, inclusive of all services within that account and according to any packaged offering you've purchased.

Edge logic and advanced content delivery control

Fastly’s content delivery capabilities are based on a heavily extended version of the Varnish caching software. Varnish software gives you direct access to content delivery, control and edge logic capabilities, via the expressive HTTP inspection and modification scripting language, Varnish Configuration Language (VCL).

Streaming content delivery

Fastly’s Streaming Delivery allows you to stream live and video-on-demand streaming content by leveraging Fastly’s native support of common streaming formats. Fastly streaming format support includes HTTP Live Streaming (HLS), HTTP Dynamic Streaming (HDS), Dynamic Adaptive Streaming over HTTP (MPEG-DASH) and HTTP Smooth Streaming.

Precision Path

Precision Path traffic routing proactively identifies network congestion and poorly performing paths and automatically switches your traffic over to better performing alternatives. This improves service availability and resilience. Provisioned at strategic locations across our global fleet, this feature is available to all Fastly customers as part of our platform.

Origin shielding

You can designate a Fastly point of presence (POP) to serve as a shield for your origin servers, thus enabling increased cache hit rates for your Fastly services and potentially protecting your origin servers from unexpected spikes in requests for content. You can optimize this shielding geographically by configuring different shield POPs for different origin server locations. Origin shielding is not enabled by default. To use it, you must specifically enable it.

Load balancing

Services configured with multiple origin servers will automatically distribute requests to those servers evenly. You can modify this default load balancing behavior with a variety of conditions and load balancing rules.

Health checks

The health of your origin servers can be monitored with configurable health checks to help ensure only responsive origin servers are being sent requests.

Fastly web interface

All Fastly accounts have access to Fastly's web interface, allowing it to be managed by multiple users within your organization. You can control each user's role, as well as control the scope of their service access and their specific permission levels. Fastly services can be created, monitored, and managed through the Fastly Web Interface via any standard, modern web browser.

Application programming interface (API)

Fastly provides an application programming interface (API), accessible via HTTPS, through which Fastly services can be created and configured, and customers can access account information and analytics.

Real-time log streaming

To help you tune the performance of your Fastly services, we support real-time log streaming to a variety of locations, including third-party services, for storage and analysis. You can find our supported logging endpoints in our list of streaming log guides. We limit real-time log usage to a monthly average of two log statements per request, per service. If you require a higher volume of logs, Fastly offers High Volume Logging.

Transport Layer Security

Fastly supports a variety of Transport Layer Security (TLS) services that allow websites and applications to serve traffic over HTTP Secure (HTTPS), providing added privacy and data security for your services and end users. All Fastly services have access to our free shared domain option, plus a variety of additional paid TLS services to meet your TLS business and technical needs.

Always-on DDoS mitigation

Fastly's globally distributed network was built to absorb Distributed Denial of Service (DDoS) attacks. As part of Fastly's standard, Full Site Delivery, all customers receive access to a combination of features inherent in Fastly Edge Cloud network capabilities that help protect the availability of your content from DDoS threats.

  • Access to origin shielding. Fastly allows you to designate a specific point of presence (POP) to host cached content from your origin servers. This POP acts as a shield that protects those servers from every cache miss or pass through the Fastly network, reducing the load that directly reaches them.
  • Automatic resistance to availability attacks. Before they're even processed by our caching infrastructure, we filter out Layer 3 and 4 attacks (e.g., Ping floods, ICMP floods, UDP abuse) as well as distributed reflection and amplification (DRDoS) attacks that rely on anonymity to abuse internet protocols (e.g., DNS and NTP).
  • Access to Fastly cache IP space. Fastly provides an API endpoint to any customer who would like to know which IP addresses our caches will use to send traffic from our CDN to your origin servers. We make this data available so you can update firewalls at your origin to ensure only our cache traffic can access your resources.
  • Custom DDoS filter creation abilities. Using custom VCL, we allow you to craft your own DDoS protection rules to protect your network from complex Layer 7 attacks. Once you identify signs of a potential DDoS attack, you can mix and match Fastly VCL with custom VCL to construct filter configurations based on a variety of client and request criteria (e.g., headers, cookies, request path, client IP, geographic location) that block malicious requests before they hit your origin servers.

In addition to these standard DDoS protection services, Fastly offers a DDoS Protection and Mitigation Service. For more information about this or any of our advanced services, including their subscription costs, contact

Pricing and billing


Billing limits for this product may be different if you've purchased a package offering or are using a product or feature trial.

Full-Site Delivery charges are based on the volume of content delivered to your end users and the location of the POPs from which that content was served. Fastly billing is done in arrears based on actual usage with month-to-date usage being available via both our web interface and APIs.


Fastly maintains partnerships with Google and Microsoft that may provide discounts on outbound data transfer traffic to customers who qualify and configure their Fastly services correctly. See our integrations guides for additional details.

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