RESENDProduct EngineerApplication / Alex Kostyniuk

I care about how a product works and how it feels, in the same commit. Six years of shipping web products, most of it making complicated things look obvious.

Product Engineer · TypeScript & React · Remote, CET

Alex Kostyniuk

Candidate / one send

Email log

re_4Xq...8fA

  • email.sent

    200

    12:04:31.204

  • email.delivered

    250

    12:04:33.019

  • email.opened

    ok

    12:07:02.884

  • webhook.delivered

    200

    12:07:03.101

  • domain.verified

    ok

    yesterday

Delivered in 1.8s, and you can see exactly why.

Live

Why we're a strong match

Your exceptional fit list, answered

Three of four

  • Products for developers

    A component library, a devtool, and a technical blog

    glasscnmellowfmtalex-posts

  • Visual taste

    glasscn: 20+ glass primitives, built for feel

  • Small, high-ownership teams

    Team lead in a startup, shipping weekly

  • DNS, webhooks, API platforms

    Yes, though email deliverability itself would be new

Why Resend should hire me

Six years of shipped products
Production web products for six years, features owned from the problem statement through UX, API, instrumentation, and the iteration after launch.
TypeScript, React, Next.js
Exactly your stack, daily. I work close enough to modern Next.js to write articles about App Router, server components, and the rendering trade-offs.
Comfortable across the stack
Node, PostgreSQL, and AWS behind the interface. I own the API contract a screen depends on rather than waiting for someone to change it.
Craft is the product
I care about interaction details to the point of publishing a component library about them. For a developer tool, polish is the difference between trusted and tolerated.
Making systems explainable
Dense operational interfaces are my favourite problem: showing what happened, in order, with the cause visible. That is the same job as an email log or a webhook trace.
Default to action
I introduced agentic workflows at my company and ship with review in the loop. Ambiguous problem, smallest honest version, then iterate on what users actually do.

Why I want to join Resend

Email is deceptively deep
One API call hides DNS, deliverability, retries, and reputation. Products that make genuinely hard infrastructure feel trivial are the ones I admire most.
Developers are my users already
My open source work exists for other developers. Doing that as the day job, for three million of them, is a straight upgrade.
Remote, small, high ownership
Fifty people across fifteen countries with autonomy to just ship is how I want to work. I am in CET, which sits inside your timezone requirement.

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.

RESENDProduct Engineer

Let's keep email feeling like one line of code.

Resend × Alex

Continue to my portfolio

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