kibin.pro

Engineering

Backends, APIsand payments

The part of the system where mistakes cost the most: load, money and servers. This is where 18 years of experience pays directly.

Engineering

Where things actually break

Backends rarely fall over from request volume alone. They fall over because the data model wasn’t built for growth, a payment was captured twice, a background job hung — and there’s no monitoring, so you hear about it from users rather than from the system.

My background here is fairly specific: the backend of the Block.io crypto wallet at roughly 300,000 users, a payment service turning over about a million dollars a day, and a distributed network of ~1500 devices under production load. Plus antifraud and DDoS protection.

Hence the habit of designing for growth, for a third-party outage, and for the payment gateway that delivers the same webhook twice.

What’s included

How the work runs

  1. Auditing what’s there

    If the system already runs, I find where the bottleneck actually is and what actually breaks. It’s often not where people were looking.

  2. Architecture and plan

    A solution outline and an order of work. Changes are split into steps that can each be shipped and rolled back on their own.

  3. Implementation

    Changes go in without stopping the running system: backward-compatible migrations, staged rollout, a way back to the previous version.

  4. Observation

    After rollout: metrics and alerts, so a deviation is visible before a user writes in about it.

Track record

Common questions

What does backend development cost?

It depends on scope: an API for a mobile app and a payment system with antifraud are different orders of magnitude. Billing is hourly. Describe the job and I’ll give an orientation.

Everything is slow. Can you find out why?

Yes — that’s a job of its own. Measurement and locating the real bottleneck first, then an estimate for the fix. The first improvements often cost noticeably less than people expect.

Which payment providers do you integrate?

Russian and international gateways, subscription models, App Store and Google Play purchases, crypto payments. Poor gateway documentation is a normal working condition, not a reason to decline.

Can you work alongside our team?

Yes. I can take a defined area — the payment layer or the infrastructure, say — and hand it over to your team with documentation.

What about security?

Rate limiting, brute-force protection, server-side receipt and webhook validation, secrets kept out of the repository, TLS. The engineering background includes antifraud and DDoS protection.

Who owns the infrastructure after delivery?

Whichever we agree. I can hand it to your administrators with documentation, or keep running it myself — also hourly.

Tell me what it has to survive

Discuss the problem