When Is One Slow Service Worth Rewriting in Go?

"Should we rewrite it in Go?" usually comes up when something is slow, the cloud bill is climbing, or a developer has read about Go's performance. Sometimes it's exactly the right move. Often it isn't.

Our main backend is Node.js, and we've used Go on client work for the specific services where it earns its place. This is how we decide.

Step 1: measure before you decide

"It's slow" isn't a diagnosis. Before any rewrite, find out:

• Which requests are slow, and how slow
• Where the time goes: the database, an external API, or the code itself
• What the load looks like: steady, spiky, or growing
• What it costs to run today

Most slowness we're asked to look at is in the database or in calls to other services. A new language won't fix a missing index or a slow third-party API. Tune those first.

Step 2: check the workload fits Go

Go is excellent at a particular shape of work:

• Handling many connections at once, like gateways, real-time feeds and busy APIs
• Background workers that process queues and files steadily
• Small, focused services where low memory use and fast start-up matter
• Command-line tools shipped as a single binary

It's less of an advantage for business apps full of forms, admin screens and changing rules, where development speed matters more than raw performance. For those, Node.js or .NET usually gets you there faster.

Step 3: rewrite one service, not the system

If the measurements point at one busy part of the system, and that part fits Go's strengths, pull just that part out into a small Go service behind a clear interface. The rest of the product stays as it is.

That keeps the risk small, the result measurable, and the team's existing knowledge intact.

Step 4: think about who maintains it

A Go service needs someone who can maintain it. If nobody on your team knows Go, factor that in: either plan to learn, or keep the service small and well documented so it's easy to hand over. We document every component we build and can maintain it from $700 a month.

Step 5: measure again

Compare the numbers before and after. If the rewrite didn't make a meaningful difference to speed or cost, it was the wrong fix, and it's better to know.

Our view in one line

Measure first, fix the obvious bottlenecks, and use Go for the one service that needs it. See our Go development page and backend technologies.

Is Go faster than Node.js?

For many workloads, especially heavy concurrency and CPU-bound work, Go is faster and uses less memory. For typical business APIs that mostly wait on databases, the difference matters less than good queries and caching.

Should we rewrite our whole backend in Go?

Rarely. Rewriting a working system is expensive and risky. Rewriting one measured bottleneck is usually the better bet. Our rewrite or refactor guide goes deeper.

What about Rust?

Rust is worth considering for the most performance-critical components, like parsers and heavy data processing. See our Rust development page.