Learn & AgentsApplication / Alex Kostyniuk

I ship product end to end—problem definition through UX, API, and instrumentation—and I have spent the last while building with agents rather than around them.

Fullstack Product Engineer · 0→1 · Stockholm

Alex Kostyniuk

Run 01 / Candidate

  1. Define
  2. Retrieve
  3. Build
  4. Instrument

Why we're a strong match

Why Sana should hire me

End-to-end by default
React and TypeScript on the front, Node and PostgreSQL behind it. I own a feature from problem definition through UX, API, and the events that tell us whether it worked.
Agent-native, not agent-curious
I introduced agentic workflows at my current company and build with them daily—keeping judgment, testing, and review in the loop rather than trusting output blindly.
Comfortable at 0→1
I turn ambiguity into a clear path to production: pick the smallest thing that proves the idea, ship it, and let what we learn decide the next move.
Product judgment
I start from the customer and business problem and work with Design to find the right feature to build, not just the one that was asked for.
Depth when it matters
I turned a ten-minute core workflow into a twenty-second one by challenging the architecture, not merely tuning it. Retrieval-heavy products need that instinct.
A force multiplier
I lead engineers today—reviewing code, setting direction, and still shipping. I get as much from raising the people around me as from my own output.

Why I want to join Sana

Agents doing real work
Agents that reach across a company's apps, knowledge, and data are the most interesting product surface in software right now, and almost none of it is a solved pattern yet.
Small teams, real ownership
Shipping customer-facing value in a small squad, with instrumentation deciding the next iteration, is exactly the loop I want to be inside.
Talent density in Stockholm
A product-obsessed team with this bar, building here, is rare. I want to be in the room with people who make me raise my own standard.

How I work.

I start with either a problem to solve or a business idea. I shape it around customer needs and technical realities, and look for a solution that can serve many customers instead of just one. Once the core is clear, I work with Design team on the experience, break it down into a focused story, and leave it ready for a developer or me to build.

How I develop features

  1. 01

    Start with an agent

    I always work with an agent. For bigger features or bugs that aren't obvious at first, I use specific skills to help it focus. For smaller tasks, I explain what needs doing and jump in.

  2. 02

    Scope the solution

    When the work needs a plan, I turn it into a detailed spec, including edge cases and what done looks like.

  3. 03

    Implement with agents

    Once the task is clear, I let one or more agents build the feature.

  4. 04

    Create feedback loops

    Browser Use, types, and tests help the agents see what they built and catch their own mistakes.

  5. 05

    Check manually

    I still open the feature and use it myself, from start to finish.

  6. 06

    Run an agent review

    I ask fresh agents to review the work and catch anything the first ones missed.

  7. 07

    Review the code

    Then I read the diff myself and fix whatever is left.

  8. 08

    Babysit the PR

    Finally, an agent watches CI and review comments until the PR is ready to merge.

Outcome

The result is a feature that has been planned, built, checked, and reviewed from a few different angles—usually in much less time.

Learn & Agents

Let's put agents to work on problems people actually have.

Sana × Alex

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