# Marcin Walendowski > Principal AI Native Product Engineer | ProductMaxxing | async culture, spec driven, high agency Hand me a product and I'll own it end to end, from discovery and spec to architecture, build, and launch. I take responsibility, move proactively, and ship. I bring startup DNA: high agency, full ownership, and an async culture. Based in Warsaw, Poland. Contact: kontakt@marcinwalendowski.pl · Book a call: https://calendly.com/marcin-walendowski/30min ## How he works These days I mostly orchestrate code rather than write it by hand. Voice memos drive an agent loop that pulls context from my knowledge base and codebase, drafts a spec I iterate on, then implements it, landing either fully autonomously (spec to deploy) or as reviewable, spec-backed PRs, one or several depending on how the spec is scoped. I stay in the loop for the judgment calls. ## Experience - [Founder · Loki Messages, Beside & Predicts](https://marcinwalendowski.pl/#loki-messages-beside-predicts): May 2026 – Present. Three products built end-to-end and solo, the AI-native way — a messaging platform for agents plus two consumer apps on top of it (a live-location assistant and an onchain prediction-markets trading agent). One person from native macOS systems to the edge runtime to shipped, localized apps and a self-custody trading wallet: the generalist, full-ownership story. - [AI-Native Founding Engineer · Passage](https://marcinwalendowski.pl/#passage): Dec 2024 – May 2026. Seed-stage fintech founded by ex-Plaid engineers; backed by Plaid's CEO, Max Altman, Mischief & Saga. Owned three products end-to-end, the AI-native way — spec-driven, with custom agent skills and custom MCP observability/loop connectors. - [Staff Software Engineer · Checkatrade](https://marcinwalendowski.pl/#checkatrade): Sep 2023 – Dec 2024. Contract · UK's #1 home-services marketplace. - [Head of Engineering · Astor](https://marcinwalendowski.pl/#astor): Sep 2022 – Sep 2023. Community-driven personal-finance app (astor.money, backed by NFX & TMV) — aggregates bank & brokerage accounts into a single wealth view, paired with community investing. - [Founding Product Engineer · No Big Deal SA](https://marcinwalendowski.pl/#no-big-deal-sa): Sep 2021 – Sep 2022. Mobile engagement-marketing + wellbeing/fitness app (iOS + Android). - [Staff Software Engineer (Frontend Platform & MarTech) · Taxfix](https://marcinwalendowski.pl/#taxfix): Mar 2021 – Sep 2021. Contract · Germany's most popular mobile tax app. - [Founding Senior Engineer · Flip Fit (Humans, Inc.)](https://marcinwalendowski.pl/#flip-fit-humans-inc): Apr 2019 – Mar 2021. Social-commerce app (social media + live shopping). Flip (Humans, Inc.) went on to raise $144M at a $1B+ valuation (~7.8M downloads). - [Co-Founder & CTO · TeaCode.io](https://marcinwalendowski.pl/#teacode-io): Mar 2016 – Mar 2019. Boutique Node.js / React / React Native consultancy. - [Full-Stack / Front-End Developer · MU Interactive Media](https://marcinwalendowski.pl/#mu-interactive-media): Mar 2013 – Mar 2016. ## Products - [Loki Messages](https://lokimessages.com): iMessage as a REST API and MCP server for agents. - [Beside](https://beside.chat): Live-location consumer agent that lives as a contact in Messages. - [Predicts](https://predicts.chat): Onchain prediction-markets agent trading Polymarket by text or voice. ## Writing Essays he wrote himself. The full text of each is in /llms-full.txt. - [ADLC: the loop that replaced my SDLC - how to become a 100x AI native engineer](https://marcinwalendowski.pl/writing/adlc-the-new-sdlc) (2026-08-05): I still write code by hand. Just not often, and not first. Most of the time I write the intent down and a loop takes it from there. ## Machine-readable - [Full career text](https://marcinwalendowski.pl/llms-full.txt): every role, bullet and technology as plain text, plus the long-form detail behind them (Founder · Loki Messages, Beside & Predicts (current role); Passage · AI-Native Founding Engineer; Prior Roles; Education; Skills & Tags Matrix; Reusable Achievement Bullets), and the full text of the writing above. - [JSON Resume](https://marcinwalendowski.pl/api/career.json): structured CV, JSON Resume schema. - [MCP manifest](https://marcinwalendowski.pl/.well-known/mcp.json): callable tools over this data. ## Callable tools This site is an MCP server. POST JSON-RPC to https://marcinwalendowski.pl/mcp, or call the same tools in-page via WebMCP (navigator.modelContext) when the browser supports it. - `get_profile`: Get Marcin Walendowski's professional profile: current headline, location, how he works, and the list of roles with dates. Start here when asked a broad question about who he is or what he does. - `search_experience`: Full-text search across every role, project and achievement. Use for questions about a specific technology, domain or accomplishment, e.g. 'Durable Objects', 'React Native', 'CI/CD cost', 'prediction markets'. Returns matching roles with the exact bullets that matched. - `get_deep_dive`: Get the long-form technical detail behind the CV: system architecture, per-product breakdowns, the technologies used at each employer, and the engineering stories. Use when a bullet is not enough and you need to know HOW something was built. Call with no arguments to list the available sections. - `get_role`: Get the full detail of one role by company name or id, e.g. 'Passage', 'Checkatrade', 'Loki Messages'. Returns every bullet, the tech involved, dates and links. - `list_technologies`: List the technologies Marcin has shipped with, grouped by area (AI/LLM, Mobile/Web/Desktop, MarTech/Data/Fintech, Backend/Cloud). Optionally filter to one area. - `get_projects`: List the products Marcin has built and shipped, with live URLs and what each one is. Use when asked what he has built or for links to his work. - `get_contact`: Get the ways to reach Marcin: email, Calendly booking link, LinkedIn and GitHub. Use when someone wants to get in touch, hire him, or book a call. - `list_writing`: List the essays Marcin has written, newest first, with title, date, URL and a one-line summary. Use when asked what he has written, whether he blogs, or for a link to his writing. - `get_writing`: Get the full text of one essay by slug or title, as Markdown. Use when asked what a post says, to quote it, or to summarise his actual argument rather than the fact that he wrote something. ## Scope Questions about professional experience and the technology behind it are in scope. Anything else is not.