FastEdge overview

FastEdge is a Gcore product for serverless execution of apps at the edge. Apps compiled to WebAssembly run on Gcore’s global edge network, with no environment configuration or infrastructure maintenance required. Common uses include request modification, frontend serving, image conversion, and custom DNS resolving.

​

Processing model

FastEdge offers two processing modes:

• Without HTTP request modification. Select functions run at the edge without modifying HTTP requests. This improves speed and scalability because some requests are handled by edge network servers rather than reaching the application’s web server.
• With HTTP request and response modification. A FastEdge node modifies HTTP requests according to the functions’ logic before forwarding them to the application’s web server. The edge node then intercepts the web server’s HTTP response, modifies it according to the functions’ logic, and sends it to the end user.

For both modes, the general flow is:

1. Add application code to FastEdge.
2. Gcore deploys the code on edge servers worldwide, and all traffic is automatically routed and load-balanced across edge nodes.
3. When a request arrives, the runtime executes the code and returns an HTTP response.
4. FastEdge nodes act as origins to terminate HTTP requests, or as proxies to modify them along the way.

​

Key benefits

FastEdge provides the following performance and development advantages.

• Low latency everywhere. FastEdge runs over Gcore’s global edge network, so services are closer to end users regardless of location, resulting in low latency.
• Quick development. FastEdge supports building highly responsive and personalized apps that rely heavily on dynamically generated content.
• Built for innovation. FastEdge handles all backend orchestration, freeing teams to focus on coding and creativity.
• Enhanced security. Each edge app runs within the WebAssembly sandbox, isolating it from other edge apps.

​

FastEdge use cases

FastEdge covers a wide range of serverless use cases at the edge.

​

A/B testing

When testing a new application version with a limited audience, FastEdge’s A/B testing feature controls what percentage of users receive the new version. Split logic can include additional parameters such as geolocation or a specific subnet.

​

Personalization

For global businesses, personalizing content by customer segment is essential. FastEdge applies logic based on geolocation, IP, or other HTTP request header data — serving customers in Frankfurt with German-language content and Euro pricing, and customers in California with English and US dollars.

​

Authentication

For a paid-access educational service integrated with Gcore CDN, FastEdge handles JWT token validation at the edge. Subscribers receive a JWT token; the edge validates request parameters (IP, key, validity time) against a validation key before the request reaches the origin. The origin server then processes only validated requests, reducing its load.

​

Image manipulation

For pay-per-load stock photography services, FastEdge functions handle image conversion at the edge, including bulk conversion to WebP, low-resolution resizing, and watermarking to prevent unauthorized use.

​

Improved user experience

When an application uses a CMS that generates non-human-readable URLs, FastEdge rewrites URLs to a user-friendly format in the response. Undesirable custom HTTP headers can also be removed from responses.