Building "Production-Grade" APIs in .NET

Many engineers build and deploy APIs into production. So we have an API running in production — does that mean it’s truly production-grade? More often than not, the answer is no. We write the code, test it locally (usually alone, on one machine, with one user), and proudly tell the business, "Hey, it’s ready!" Maybe there’s even a QA environment where someone from product gives it a quick click-through and confirms, "Looks good to me!" And then... reality checks in. You get a call on the weekend: “Users can’t log in.” Or worse: “A customer placed an order, and it’s gone.” Now you're scrambling, thinking: “I wish I’d added logs there.” “Why didn’t we catch this earlier?” “How are we supposed to debug this in production?” If that scenario feels familiar, this post is for you. Let’s walk through what I consider the minimum bar for an API to be truly production-grade — and how to build one in .NET. What Qualifies as “Production-Grade”? Most APIs “work” during development. But production-grade APIs are designed to behave predictably under pressure; when traffic spikes, something fails, or a customer is relying on your system to do its job. For me, production-grade doesn’t mean “it passes QA”, it means the system is built in a way that makes life easier for engineers and consumers alike. It means: The API is intuitive to use. Consumers don’t have to ask how it works. They don’t open tickets asking why they got a 500. It’s predictable, self-documenting, and consistent. It’s observable. You can tell what the system is doing, when it fails, and why. You find out something’s wrong before your customers do; no surprise calls at 10 PM. It’s resilient. Every API that handles load will eventually fail; so you build in circuit breakers, retries, and rate limits before you need them. It’s secure by default. If your API is public, someone will try to break it. Don’t assume good will from your users. Protect your business. Especially in B2B software where one leak or exploit can damage your reputation permanently. It’s safe for your users. No user data in logs. No stack traces exposed. If you break that trust, users will hate you, and you may land in legal trouble, too. It’s automated and testable. You don’t publish from your machine. Deployment should be a repeatable, automated pipeline with proper testing. Even if your business doesn’t release multiple times per day (like in medical or aerospace), you still benefit from CI/CD; because you always have a shippable, tested build and fast feedback loops. A "Production-Ready" Framework to Follow This mindset can be distilled into five key areas. Not as a checklist, but as a framework for designing APIs that last beyond dev and QA. That’s why I break it down into five core areas. A framework I use every time I design an API I expect to survive real-world use. 1. Developer Experience & Documentation Even the most reliable API will fail if it’s confusing to consume. Clean routes, consistent behavior, meaningful errors, versioning, and good documentation are essential. 2. Observability & Diagnostics Structured logging, traces, metrics, and health checks let you understand what’s happening in production, and debug issues when they inevitably arise. 3. Resilience & Stability Your API must handle real-world failures: retries, circuit breakers, timeouts, fallback strategies, and rate limiting help it stay functional under stress. 4.Security & Safety Authentication, authorization, input validation, exception handling, and proper error reporting — all critical to protect user data and prevent abuse. 5. Deployment & Automation CI/CD pipelines, infrastructure as code, testing pyramid, smoke and load testing, and safe deployment practices (e.g., blue/green, canary). These ensure your API can be updated often without fear. This post is part of my blog series: Building Production-Grade APIs in .NET. Visit my blog for the rest of the series and deeper technical posts.

May 4, 2025 - 12:01

Building "Production-Grade" APIs in .NET

Many engineers build and deploy APIs into production.

So we have an API running in production — does that mean it’s truly production-grade?

More often than not, the answer is no.

We write the code, test it locally (usually alone, on one machine, with one user), and proudly tell the business, "Hey, it’s ready!"

Maybe there’s even a QA environment where someone from product gives it a quick click-through and confirms, "Looks good to me!"

And then... reality checks in.

You get a call on the weekend:

“Users can’t log in.”

Or worse:

“A customer placed an order, and it’s gone.”

Now you're scrambling, thinking:

“I wish I’d added logs there.”

“Why didn’t we catch this earlier?”

“How are we supposed to debug this in production?”

If that scenario feels familiar, this post is for you.

Let’s walk through what I consider the minimum bar for an API to be truly production-grade — and how to build one in .NET.

What Qualifies as “Production-Grade”?

Most APIs “work” during development. But production-grade APIs are designed to behave predictably under pressure; when traffic spikes, something fails, or a customer is relying on your system to do its job.

For me, production-grade doesn’t mean “it passes QA”, it means the system is built in a way that makes life easier for engineers and consumers alike.

It means:

The API is intuitive to use. Consumers don’t have to ask how it works. They don’t open tickets asking why they got a 500. It’s predictable, self-documenting, and consistent.
It’s observable. You can tell what the system is doing, when it fails, and why. You find out something’s wrong before your customers do; no surprise calls at 10 PM.
It’s resilient. Every API that handles load will eventually fail; so you build in circuit breakers, retries, and rate limits before you need them.
It’s secure by default. If your API is public, someone will try to break it. Don’t assume good will from your users. Protect your business. Especially in B2B software where one leak or exploit can damage your reputation permanently.
It’s safe for your users. No user data in logs. No stack traces exposed. If you break that trust, users will hate you, and you may land in legal trouble, too.
It’s automated and testable. You don’t publish from your machine. Deployment should be a repeatable, automated pipeline with proper testing. Even if your business doesn’t release multiple times per day (like in medical or aerospace), you still benefit from CI/CD; because you always have a shippable, tested build and fast feedback loops.

A "Production-Ready" Framework to Follow

This mindset can be distilled into five key areas. Not as a checklist, but as a framework for designing APIs that last beyond dev and QA.

That’s why I break it down into five core areas. A framework I use every time I design an API I expect to survive real-world use.

1. Developer Experience & Documentation

Even the most reliable API will fail if it’s confusing to consume. Clean routes, consistent behavior, meaningful errors, versioning, and good documentation are essential.

2. Observability & Diagnostics

Structured logging, traces, metrics, and health checks let you understand what’s happening in production, and debug issues when they inevitably arise.

3. Resilience & Stability

Your API must handle real-world failures: retries, circuit breakers, timeouts, fallback strategies, and rate limiting help it stay functional under stress.

4.Security & Safety

Authentication, authorization, input validation, exception handling, and proper error reporting — all critical to protect user data and prevent abuse.

5. Deployment & Automation

CI/CD pipelines, infrastructure as code, testing pyramid, smoke and load testing, and safe deployment practices (e.g., blue/green, canary). These ensure your API can be updated often without fear.

This post is part of my blog series: Building Production-Grade APIs in .NET.

Visit my blog for the rest of the series and deeper technical posts.