What is the difference between REST and gRPC?

REST uses JSON over HTTP/1.1, while gRPC uses Protocol Buffers (binary) over HTTP/2. gRPC is significantly faster and more efficient for internal microservice communication.

How to reduce API latency?

Latency can be reduced by using persistent connections (Keep-Alive), optimizing database queries, implementing caching (Redis), and choosing a more efficient serialization format like Protobuf.

When should I use GraphQL?

GraphQL is best when the frontend needs highly flexible data fetching or when you're aggregating data from many different microservices into a single request.

Architecting High-Throughput APIs: Beyond REST and GraphQL

The Scaling Wall

Every backend engineer eventually hits a wall where standard REST APIs become too slow. Whether it's the overhead of JSON parsing or the limitations of HTTP/1.1, scaling to millions of concurrent users requires a rethink of how data moves.

The Scratch Level: REST with Best Practices

Before jumping to advanced protocols, ensure your REST APIs are optimized. Use Compression (Gzip/Brotli), implement E-tags for caching, and ensure your database indexes match your query patterns. Most "scaling" problems are actually "unoptimized query" problems.

Intermediate: The Case for GraphQL

GraphQL solves the Under-fetching and Over-fetching problems. It's excellent for complex frontends, but it introduces N+1 query problems on the backend. To fix this, you must use Dataloaders to batch database requests.

Advanced: gRPC and Connect

In 2026, internal microservices almost exclusively use gRPC or the Connect Protocol. By using Protocol Buffers (Protobuf) instead of JSON, we reduce payload sizes by up to 80% and eliminate parsing latency.

Combined with HTTP/2 multiplexing, a single connection can handle hundreds of concurrent streams without the overhead of repeated handshakes.

Real-Time Infrastructure

WebSockets: Best for bi-directional, long-lived connections.
Server-Sent Events (SSE): Best for one-way streams (like AI chat responses).
WebTransport: The next-gen protocol for ultra-low latency over QUIC.

Frequently Asked Questions

How do I choose between gRPC and REST?

Use gRPC for internal service-to-service communication where speed and type-safety are critical. Use REST (or Connect) for public-facing APIs where ease of use and browser compatibility are more important.

What is an N+1 problem in GraphQL?

It happens when a query for a list of items results in one database query for the list, plus N additional queries for the details of each item. Use Dataloader to batch these into two queries instead of N+1.

How to handle rate limiting effectively?

Implement rate limiting at the API Gateway level (using tools like Kong or Nginx) rather than in the application code. Use the Token Bucket algorithm for smooth traffic shaping.

A scalable API is not one that never fails, but one that fails gracefully under load.