why vercel does not run full nodejs runtime on edge servers

Vercel, as a platform, focuses on providing high-performance and scalable hosting for frontend applications and static sites. While Vercel does support serverless functions (referred to as Edge Functions) that can execute at the edge of their network, there are limitations and reasons why running a full Node.js runtime directly on edge servers is not feasible or practical:

1. Limited Resources:

   • Edge servers typically have limited resources (CPU, memory, disk space) compared to centralized cloud servers or data centers. This limitation is essential for maintaining low latency and high availability across a distributed network.
   • Running a full Node.js runtime with its associated libraries and dependencies would require significantly more resources than what edge servers typically provide.

2. Performance Considerations:

   • Edge servers are optimized for fast content delivery and processing lightweight tasks close to end-users. They are not designed to handle the compute-intensive workloads that a Node.js runtime might demand, especially for applications requiring extensive processing or large memory footprints.

3. Scaling and Consistency:

   • Edge servers operate in a distributed environment across multiple geographical locations. Ensuring consistency and synchronization of a full Node.js runtime across these distributed edge locations would be complex and could introduce operational challenges.
   • Serverless architectures, where code executes in response to events (like HTTP requests), are better suited for edge computing scenarios because they allow for dynamic scaling and efficient resource allocation based on demand.

4. Security and Isolation:

   • Running a full Node.js runtime on edge servers could pose security risks, as edge servers are exposed to potentially untrusted user requests from the internet. Serverless functions (Edge Functions) are designed with security and isolation in mind, executing within managed environments that provide sandboxing and controlled access to resources.

5. Service Scope and Optimization:

   • Vercel’s primary focus is on optimizing frontend and static site deployments, where content can be cached and delivered quickly from edge locations. This aligns with the platform’s goal of providing a highly responsive and efficient hosting solution for static assets and dynamic content handled via serverless functions.

Edge Functions (Serverless Functions) on Vercel

Instead of running a full Node.js runtime on edge servers, Vercel provides Edge Functions, which are serverless functions designed specifically for execution at the edge of their network:

• Purpose: Edge Functions allow you to execute lightweight JavaScript functions in response to HTTP requests at Vercel’s edge locations.
• Execution Model: They are triggered by events (e.g., HTTP requests) and are designed to handle tasks such as authentication, API routing, or lightweight data processing.
• Benefits: Edge Functions leverage the proximity of edge servers to users, ensuring low-latency responses while offloading compute-intensive tasks to centralized data centers when necessary.