He Promised Rust Would Save Us — It Ended the Company Instead
It started with a promise. Not a business plan, not a roadmap — a promise. “Rust will fix everything.” We were tired of Go’s race conditions, Node’s memory leaks, and Python’s performance anxiety. Rust sounded like freedom — no nulls, no segfaults, no fear. And honestly? We bought it. I remember the CTO — let’s call him Arun — standing in front of a whiteboard, eyes bright with conviction. “Memory safety,” he said, like it was a religion. “Zero-cost abstractions. Compile-time guarantees. This will make us unstoppable.” We nodded. Because it felt right. Because safe code had to mean safe business. Right? …yeah.
The Migration That Started as a Meme
At first, it was a side experiment.
A small service — billing-worker — rewritten in Rust to “test the waters.”
The Go version handled around 1,200 transactions per second. The Rust one?
We benchmarked it.
1,900/sec.
Faster. Cleaner. Cooler.
The team Slack lit up like we’d just launched a rocket.
$ wrk -t4 -c100 -d30s http://localhost:8080/process
Requests/sec: 1923.44
Latency: 4.23ms
Arun dropped the line that sealed our fate:
“If it’s this fast for billing, imagine what it’ll do for everything else.”
So we imagined.
And then we rewrote. Everything.
The Borrow Checker vs. Human Patience
The first few weeks felt… romantic.
Rust looked beautiful. Its compiler talked back. It cared.
But then came the friction.
We had junior devs staring at the screen, whispering at cargo check like it was a stubborn oracle.
error[E0502]: cannot borrow `user` as mutable because it is also borrowed as immutable
--> src/payment.rs:47:9 |
42 | let name = &user.name;
| ---------- immutable borrow occurs here
47 | user.balance -= amount;
| ^^^^^^^^^^^^^ mutable borrow occurs here
I still remember Ravi — one of our best Go developers — throwing his headphones down. “I just wanted to subtract a number,” he said. He looked tired. Really tired. And honestly? I didn’t blame him. We had replaced runtime errors with compile-time therapy sessions. The borrow checker wasn’t saving us. It was breaking us. Slowly.
The Day the Build Broke — and So Did We
Six months in, half the codebase was in Rust.
The other half was still in Go, held together by a web of gRPC calls and false optimism.
Then one Friday night, the CI failed.
A dependency update in our Rust crates had broken ABI compatibility with a C library.
Our build pipeline froze.
Docker images wouldn’t compile. Our staging deployment died.
error: linking with `cc` failed: exit code: 1
note: undefined reference to `ssl_ctx_new`
That line still gives me chills.
We spent 19 hours trying to patch it. Arun stayed up the whole night, eyes red, mumbling about musl and static linking.
By Saturday morning, staging was gone. By Sunday, so was production.
Because, of course, our graceful rollback plan hadn’t accounted for half the stack being rewritten in a language nobody fully understood.
Our incident report said “integration failure.”
But the truth?
It was ego. Wrapped in curly braces.
The Performance That Never Paid Off
Here’s the cruel irony:
Rust did make our code faster.
Just… not where it mattered.
Sure, CPU usage dropped by 30%. Memory leaks vanished. Latency graphs looked like art.
But our customers didn’t notice.
They cared about features. We cared about futures.
We lost three months rewriting an API handler that could’ve been improved with a single database index.
CREATE INDEX idx_user_orders ON orders(user_id);
That line would’ve saved more time — and more money — than our entire rewrite.
But we were chasing purity.
And purity doesn’t pay AWS bills.
When Rust Meets Runway
By the time our investors checked in, we had burned through 80% of our Series A.
Our velocity chart looked like a heart monitor on flatline.
Every new engineer needed a month just to get the toolchain working.
cargo, rustup, nightly, mold, llvm — it was alphabet soup with segfault seasoning.
I remember one junior dev saying:
“This language makes me feel stupid.”
And I knew exactly what he meant.
Rust made us careful — too careful.
Every pull request turned into a debate about lifetimes and ownership semantics.
We stopped shipping.
Faster. Safer. Stronger.
Until we weren’t shipping anything.
The Human Side of “Safe” Code
People don’t talk enough about how technical safety can create emotional risk.
Rust forces you to think before you write.
Which is great… unless your business model depends on writing fast.
And weirdly enough, the more the compiler “protected” us, the less we trusted ourselves.
Every failure felt personal — not “the code broke,” but “I didn’t understand the borrow checker.”
I’d see Slack messages at 2 a.m.:
“Anyone know how to fix lifetime errors in async closures?”
We were building a company, but living inside a compiler tutorial.
The End (and the Epiphany)
The company didn’t explode. It quietly stopped existing.
One by one, people left. The last PR merged was titled:
refactor: remove unsafe blocks we never needed anyway
That one hurt.
Rust didn’t kill us. Ambition did.
But Rust gave ambition the tools to do it faster.
And I don’t hate the language — I still use it for personal projects.
But every time someone says, “Let’s rewrite this in Rust,”
I feel a twitch.
Because I’ve seen what happens when you optimize the system before you understand the problem.
What I Learned (the hard way)
- Safety isn’t speed. Compile-time guarantees mean nothing if you never reach production.
- Tools don’t save teams. Communication does.
- Technical debt isn’t bad — emotional debt is worse.
- The cleanest rewrite is the one you never do.
And maybe, just maybe — “fast” isn’t the same as “forward.”
What About You?
What’s the most painful “rewrite” you’ve ever been part of?
Did it make things better… or just harder to explain?
Because sometimes, progress isn’t about moving fast or slow.
It’s about knowing when to stop running.