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I build and review production software systems.

I'm a senior full-stack engineer in Kyiv. I work on applications, integrations and the systems behind them, including AI-powered features.

Discuss a project Read my notes
Olha Shevchenko
Olha

Making things

Build

A feature doesn't stop at the screen.

I design and implement application workflows, APIs and integrations, with the data, background jobs and deployment work they need.

The work I take on
  1. InterfaceWhat someone needs to do
  2. BackendThe rules and integrations
  3. DataWhat has to stay true
  4. ProductionTests, deployment, debugging

My usual tools: Node.js, TypeScript, Next.js, PostgreSQL and AWS.

Reading what is already there

Review

I investigate architecture, authorization, reliability and production behaviour. The report separates what the evidence supports from what still needs checking.

How I review a system

For an acquisition: technical due diligence.

From the sample shelf

PRODUCTION DIAGNOSTICEXTRACT / 03

Illustrative extract. Fictional company; all findings and evidence invented.

Finding & urgency

Deploy pipeline lacks reliable health checks and rollback

Finding 3 · Urgent

Supporting evidence

Observed symptom
A deployment left the application degraded until a manual revert.
Evidence
The deployment check accepted running tasks without establishing that they could serve application traffic.

Recommended action

Fix
Add a health check for DB, Redis and a critical downstream dependency, and require CI smoke tests before declaring deploy success.
Effort
2 to 3 days. The memo names this the highest-impact fix.

Condensed from the illustrative production-triage memo. Full sample, 4 pages

What did 'healthy' actually mean?

Here, running tasks were enough to pass the deployment check. I'd want to see whether it exercised the application and its dependencies.

A question about the illustrative sample above.
Four sample documents. Open to read.

Things I've been thinking about

Notes, questions,
and the occasional finding.

All writing

Over to you

What are you working on?

Something to build, or a system you want to understand better.

Tell me about it