Serverless and edge architectures have changed how today’s apps are built, which also means they’ve also changed how they must be secured.
Serverless and edge architectures have changed how today’s apps are built, which also means they’ve also changed how they must be secured. If you’re deploying to AWS Lambda, Vercel Functions, Cloudflare Workers, or running distributed microservices across regions, your security model can’t rely solely on a traditional perimeter. The architecture itself distributes execution, scale, and exposure.
This guide explains:
If you’re building modern infrastructure, this is the security model you need to understand.
Serverless security refers to protecting applications that run on event-driven platforms where functions are spun up on demand, such as AWS Lambda, Vercel Functions, and other function-as-a-service environments.
Unlike traditional servers, serverless workloads:
Security in this model focuses less on hardening long-lived hosts and more on protecting individual functions, request flows, and service interactions. The core challenge is that every function becomes its own entry point.
In a monolithic system, traffic typically flows through a centralized gateway where that gateway becomes the main enforcement point for rate limiting, filtering, and access control. Distributed architectures break that assumption.
Each serverless function or edge route can accept requests directly. A login endpoint, webhook handler, AI inference API, and background trigger may all be independently invokable. An attacker doesn’t need to take down your entire application, they only need to target one expensive function.
Edge runtimes execute close to users for latency reasons. If every request had to be routed back to a centralized security layer, you would undermine the performance benefits of edge deployment. Security controls must respect latency constraints.
Microservices communicate internally over HTTP or RPC. Retry storms, misconfigurations, or compromised credentials can generate traffic that looks legitimate at the network layer but still overwhelms downstream services. Perimeter security cannot see intent or identity context inside those calls.
In distributed systems, the security boundary is not just at the edge of the network, it exists at every execution environment.
Firewalls, WAFs, and API gateways still play important roles. They provide:
But they operate at the infrastructure layer which means they generally lack:
In serverless and microservices environments, relying exclusively on perimeter controls creates gaps. Some endpoints receive strong protection, while others rely on implicit trust. That inconsistency is where abuse often occurs.
Application-layer security enforces protection inside the request lifecycle of each service or function. Instead of inspecting traffic only at the network boundary, it evaluates:
For example, identity-aware rate limiting can combine IP address, email, API key, or account ID into enforcement logic, that is far more precise than simple IP throttling at a firewall. Because enforcement runs inside the service, it scales horizontally and does not require introducing a centralized bottleneck In distributed architectures, this placement is critical.
If you are securing serverless functions, edge deployments, or microservices, these best practices should guide your architecture.
Arcjet is designed to integrate directly into application runtimes such as serverless functions, edge handlers, and microservices. Rather than assuming all enforcement happens at a centralized gateway, it enables protection logic to run alongside application logic.
This approach:
It complements, rather than replaces, API gateways and WAFs by adding contextual, identity-aware enforcement inside distributed execution environments. Arcjet exists as part of a defense in depth strategy where you delegate generic protections to the platform with Arcjet customized to protect high-value endpoints. Generic solutions are great for protecting against volumetric attacks, but application context makes the difference between distinguishing between an attack and legitimate requests from your largest user. That’s where Arcjet shines.
Serverless platforms reduce some infrastructure risks because providers manage the underlying host environment. However, they do not eliminate application-layer risks. Each function remains an exposed entry point that must enforce its own protections.
Yes, but with a different purpose depending on where it’s deployed. Traditional WAFs filter known attack patterns at the network edge. Arcjet Shield WAF provides protection directly inside your application, alongside identity-aware rate limiting and abuse controls.
For many serverless and edge architectures, enforcing WAF and application-layer protection where your code runs is a better fit than relying solely on a centralized network WAF.
You enforce rate limiting inside the Lambda handler by evaluating request context before running expensive logic. This allows limits to scale with the function and use identity-aware signals such as IP, user ID, or API key.
Tools like Arcjet provide built-in rate limiting and abuse controls that run directly inside your Lambda functions, rather than relying only on upstream gateways.
Inconsistent enforcement and internal service abuse are major risks. When services trust each other implicitly, misconfigurations or compromised components can cause cascading failures.
Serverless, edge, and microservices architectures improve scalability and performance by distributing execution, your security must follow the same pattern.
If enforcement remains centralized while everything else becomes distributed, you introduce blind spots, inconsistent protection, and unnecessary latency. Modern systems require a layered approach: infrastructure controls at the network boundary combined with application-layer enforcement inside each service and function.
Arcjet is built for this distributed model. Instead of assuming security lives only at a gateway, it runs alongside your application code inside serverless functions, edge handlers, and microservices where identity, context, and intent are available. This allows rate limiting, abuse prevention, and WAF protection to scale horizontally with your architecture without creating a centralized bottleneck.
As architectures evolve, security strategies must evolve with them, and distributed systems require distributed protection and enforcement that lives where your code runs.
If you are building on Lambda, Vercel, or at the edge, security should be part of your runtime, not bolted on afterward. Explore how Arcjet fits into your architecture.
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