When Serverless Is the Right Choice
Serverless architecture solves real problems beautifully — but it's not a universal solution. Choosing the right architecture means understanding where serverless excels and where traditional approaches work better. Often, the best answer is a hybrid.
Where Serverless Shines
Variable and unpredictable traffic is serverless's sweet spot. If your application sees traffic spikes during certain hours or events, serverless scales automatically without you paying for idle capacity during quiet periods.
Event-driven workloads fit naturally. Processing uploaded files, responding to webhooks, handling form submissions — these discrete, triggered operations map perfectly to serverless functions.
Infrequent background jobs benefit enormously. A daily report that runs for 30 seconds doesn't need a server running 24/7. Serverless lets you pay only for those 30 seconds.
Prototypes and MVPs launch faster with serverless. You skip infrastructure setup entirely and focus on building features. If your product succeeds, you can always migrate later.
Where Serverless Struggles
Constant high traffic changes the economics. When your servers would run at high utilization anyway, traditional compute often costs less and performs more predictably.
Long-running processes hit hard limits. Most serverless platforms cap execution at 15 minutes. Batch jobs, video processing, or complex calculations that exceed this limit simply won't work.
WebSocket connections and real-time features are challenging. Serverless functions are designed to start, execute, and stop. Maintaining persistent connections requires workarounds or different architectures entirely.
Stateful applications need external state management. Every function invocation starts fresh, so you must store state in databases or caches. This adds complexity and latency.
Low-latency requirements suffer from cold starts. When a function hasn't run recently, it takes time to initialize — sometimes hundreds of milliseconds. For applications where every millisecond matters, this unpredictability is problematic.
The Hybrid Approach
Most production systems combine approaches strategically. A common pattern uses serverless for HTTP APIs through an API Gateway, traditional containers for long-running background workers, serverless again for scheduled tasks and event processing, and managed databases for persistent storage.
This hybrid model captures serverless benefits — automatic scaling, pay-per-use pricing, reduced operations — while using traditional compute where it makes more sense.
Making the Decision
Ask yourself: Is traffic variable or constant? Are operations short or long-running? Do you need persistent connections? How sensitive is the application to latency? What's your team's operational capacity?
There's no universally correct answer. The best architecture matches your specific requirements, constraints, and team capabilities.