Akamai CDN
Enterprise-grade CDN for app, API, and media delivery at global scale
Varnish Cache
Lightning-fast HTTP accelerator for high-traffic web services
Varnish Cache delivers ultra-low latency content delivery by caching HTTP responses, offering a programmable VCL language, multi-threaded performance, and extensive testing for reliable edge acceleration.
Overview
Overview
Varnish Cache is a high-performance HTTP accelerator designed to cache web content and serve it with minimal latency. It operates as a reverse proxy, intercepting requests and delivering cached responses, which reduces load on origin servers and speeds up user experiences.
Capabilities & Deployment
The core of Varnish is written in C and leverages a multi-threaded architecture to handle thousands of requests per second. Custom request handling is achieved through VCL (Varnish Configuration Language), allowing fine‑grained control over caching policies, header manipulation, and backend selection. The project includes a comprehensive automated test suite run via CircleCI and the vtest framework, ensuring stability across supported platforms. Varnish can be built from source on Linux/Unix systems and integrated into existing infrastructure, with commercial support available for enterprise deployments.
Highlights
Programmable request handling via VCL
Multi-threaded architecture for high throughput
Robust automated testing with CircleCI and vtest
Optimized for HTTP/1.1 caching and edge delivery
Pros
- Exceptional request throughput and low latency
- Fine-grained control through VCL scripting
- Active community and commercial support options
- Extensive automated test suite ensures stability
Considerations
- Steep learning curve for VCL
- TLS termination requires external solutions
- Primarily Linux/Unix; limited Windows support
- No built-in graphical management interface
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Fit guide
Great for
- High-traffic websites needing fast content caching
- API endpoints where response latency is critical
- CDN edge nodes for static asset acceleration
- Enterprises requiring customizable request logic
Not ideal when
- Small static sites with minimal traffic
- Environments that demand native TLS handling
- Windows-only deployments
- Teams preferring out-of-the-box UI dashboards
How teams use it
E‑commerce site acceleration
Reduced page load times and lower backend database load during peak sales.
API response caching
Improved latency for frequent API calls while preserving freshness via VCL rules.
News portal edge caching
Fast delivery of static articles and images to global readers.
CDN edge node integration
Efficient caching of static assets, decreasing origin bandwidth consumption.
Tech snapshot
C92%
M43%
Python3%
Shell1%
Makefile1%
VCL1%
Frequently asked questions
What programming language is Varnish written in?
Varnish is primarily implemented in C.
How do I customize caching behavior?
Use VCL (Varnish Configuration Language) files to define policies, header handling, and backend selection.
Does Varnish provide built-in TLS termination?
TLS termination is not native; it is typically handled by a front‑end proxy such as Nginx or HAProxy.
Where can I get commercial support?
Commercial support and services are offered through the Varnish HTTP Cache Business page.
How can I test my VCL configuration?
Varnish includes the vtest framework for automated testing of VCL scripts.
Project at a glance
Active- Stars
- 4,037
- Watchers
- 4,037
- Forks
- 401
Repo age10 years old
Last commit2 days ago
Primary languageC
Last synced 11 hours ago