CO-FOUNDER AND CTO · STACKLIST
Martina Zrnec
Building Stacklist and the Atomic Content Protocol: the knowledge layer for the AI-first web. Ten years shipping software, from Zagreb to New York.
Key facts
- Role
- Co-founder and CTO, Stacklist
- Experience
- 10+ years building software
- Based in
- Zagreb, Croatia
- Latest workshop
- Build Your Own AI Agent
ABOUT MARTINA
Co-founder and CTO of Stacklist
Martina Zrnec is the co-founder and CTO of Stacklist, the platform that turns saved content into structured, AI-readable knowledge. She leads engineering and product, and is the architect of the Atomic Content Protocol (ACP), an open standard that lets AI agents read and cite curated content without re-parsing the page it came from.
She has been shipping software since 2014. After a master's in informatics and telecommunications at the University of Zagreb, she built payment and members-club products in New York, led the team behind Vibby's video platform and its CI/CD and AWS infrastructure, and from 2019 worked through Toptal as a Verified Expert in Engineering: front-end lead, engineering manager and fractional CTO for clients including CIAL Dun & Bradstreet, Kencko and Exemplar Human Services.
Today she is based in Zagreb and works wherever the product needs her. She taught Build Your Own AI Agent, a half-day workshop on the AI Engineers track at Web Summer Camp 2026 in Opatija, co-hosts the Building Stacklist podcast with co-founder Kyle Hudson, and writes about the build in public. She is a builder first, a systems thinker always, and convinced the next version of the web belongs to curators.
Quote
The next version of the web belongs to curators. We are building the infrastructure that makes curation legible to both humans and machines.
JOURNEY
10+ years of shipping
- 2010 - 2015
- BSc and MSc, University of ZagrebInformatics and telecommunications, followed by a first developer role writing SQL procedures and WPF interfaces at Hypo Alpe-Adria Bank.
- 2015 - 2016
- Web developer, Magnises (New York)Built the Stripe payment flow, Mailchimp notification system and event maps for a members' club product shipping weekly.
- 2016 - 2019
- Web developer and team lead, VibbyLed the team behind a video-player management system and a YouTube Chrome extension, and owned the Jenkins CI/CD pipeline and AWS infrastructure.
- 2019 onward
- Toptal, Verified Expert in EngineeringFull-stack and leadership engagements for CIAL Dun & Bradstreet, Celebrate GmbH and Exemplar Human Services, plus engineering-manager work at Kencko.
- 2022
- Web Summit, LisbonOn stage with Toptal's leadership team, and helped run the Women in Tech lounge alongside women building in Kyrgyzstan, Australia and Ukraine.
- 2024 onward
- Co-founder and CTO, StacklistOwns engineering, product and AI strategy for the curation layer of the internet. Bootstrapped the first year, then backed by Blue Startups and Connetic Ventures.
- May 2026
- Open-sourced the Atomic Content ProtocolPublished ACP as an open standard so any publisher can hand AI agents a structured envelope instead of a page to scrape.
- July 2026
- Web Summer Camp 2026, OpatijaHalf-day workshop, Build Your Own AI Agent, opening the AI Engineers track on the first morning of the conference.
SPEAKING
Stages, workshops and the mic
- Web Summer Camp 2026
- Build Your Own AI Agent, half-day workshopAI Engineers track, Opatija, Croatia, 2 to 4 July 2026. Two sessions on the opening morning, straight after the keynote.
- Web Summit 2022
- Toptal panel and Women in Tech loungeLisbon. Shared the stage with Toptal's leadership team and helped run the lounge for hundreds of women working in tech.
- Building Stacklist
- Podcast, co-hosted with Kyle HudsonAn unscripted record of building a company: fundraising, product calls, team growth, and the parts that never make the highlight reel.
FEATURED STACKS
What Martina is building and curating
19My AI Builder Stack
The tools, platforms, and infrastructure I rely on as an AI builder — from coding IDEs (Cursor, Windsurf) and AI models (OpenAI, Claude) to agent frameworks (LangChain, Hermes), deployment infra (Vercel, Railway, Daytona), data & search (Pinecone, Firecrawl, Jina, Apify), voice A
13Basketball Courts to Play in Croatia
This curated collection is your ultimate guide to discovering the best outdoor and indoor basketball courts across Croatia, perfect for travelers and basketball enthusiasts. It features iconic locations like the world-famous Dubrovnik City Wall Rooftop Court, alongside top courts in Zagreb, Split, and Zadar. Whether you're looking to hoop with a stunning sea view or explore Croatia's vibrant basketball culture, this resource provides essential information to find your next game.
14Startup or Geeky Series / Movies
This curated collection features 14 compelling TV series and movies, perfect for anyone looking to dive into the world of startups, technology, finance, and geek culture. Designed to inspire and engage, it's an essential resource for aspiring entrepreneurs, developers, tech enthusiasts, and business leaders seeking content that puts them in 'startup/execution/developer mode'. Discover stories of innovation, hacking, entrepreneurial journeys, and financial sagas, from the rise of tech giants to groundbreaking market disruptions.
WRITING
Notes from the build
Martina writes about building Stacklist while it is still being built: the architecture calls, the benchmarks, and the parts that do not resolve neatly.
- We benchmarked an 84% token reduction. Then we open sourced the protocol. - building ACP, and sitting with the part we cannot solve.
- A CTO diary: the day the system moved, and so did I - how rebuilding the foundation rebuilt parts of her too.
- Coverage is not overlap - the decisions still get made; the conversations do not happen.
- Falling into the AI rabbit hole (and trying to climb out) - the never-ending drop of game changers.
- When praise feeds doubt - feeling like a fraud even when you are winning.
FAQ
Questions about Martina and Stacklist
What is Stacklist and what does Martina do there?
Stacklist is a curation platform that makes saved content structured and discoverable by both people and AI engines. Martina Zrnec is its co-founder and CTO: she owns engineering, product architecture and AI strategy, and is the primary author of the Atomic Content Protocol (ACP).
What is the Atomic Content Protocol (ACP)?
ACP is an open standard from Martina and the Stacklist team. It wraps content in a structured envelope - summary, tags, key entities, classification - so an AI agent can read and cite it directly instead of scraping the page. In a live read of one Wikipedia article, the full body cost roughly 25,000 tokens and the ACP envelope roughly 350.
What did Martina do before Stacklist?
She has been building software since 2014, after a master's in informatics and telecommunications at the University of Zagreb. She built payment products at Magnises in New York, led the team and infrastructure behind Vibby's video platform, and from 2019 worked through Toptal as a Verified Expert in Engineering - front-end lead, engineering manager and fractional CTO for clients including CIAL Dun & Bradstreet, Kencko and Exemplar Human Services.
Does Martina speak at conferences?
Yes. She ran Build Your Own AI Agent, a half-day workshop opening the AI Engineers track at Web Summer Camp 2026 in Opatija, Croatia. In 2022 she spoke at Web Summit in Lisbon with Toptal's leadership team and helped run the Women in Tech lounge.
Can I book Martina for a talk, workshop or podcast?
Yes. The quickest route is to book a slot directly at cal.com/martina-zrnec, or use the contact form on this page. Usual subjects: building AI agents, MCP, making content readable by machines, and what an AI-first web does to search and discovery.
Where does Martina write?
On Substack, at martinazrnec.substack.com, where she publishes essays on the engineering and the emotional reality of building Stacklist - including the post announcing ACP as open source.
Does Martina have a podcast?
Yes. She co-hosts Building Stacklist with co-founder Kyle Hudson: an unscripted show on fundraising, product decisions, team growth and everything in between.
Where is Martina based?
Zagreb, Croatia, and wherever the product needs her - including New York, and Hawaii for the Blue Startups accelerator chapter of Stacklist's growth.
Get in touch with Martina
Founder intros, podcast pitches, partnership ideas, or just to say hi.