How to use Claude to build a European startup map
A nontechnical founder manually mapped startups, moved a directory from Lovable to Claude Code, learned its data tools and supplied the simpler solution to a logo-loading performance problem.
news.ycombinator.com
Prompt to try
Editorial adaptation, not the source author’s exact prompt. Replace bracketed inputs and review tool permissions first.
Help build [regional startup directory] from [curated company data], with locations, funding stages and hiring links. Explain [database services] and APIs as we work. Investigate slow loading of [logo assets], compare simpler alternatives to clustering and flag database access controls for review.
Reach people exploring AI agents
See placements →What happened
The directory reached 2,300+ curated startups; after 90 days the author reported 18,000+ monthly visitors and 683 applications started.
Reported by denysjw on Hacker NewsHow the agent did it
- Manually mapped startups in Belgium, then the Netherlands.
- Built with Lovable and subsequently migrated to Claude Code.
- Tried multiple clustering approaches to reduce logo-loading delays.
Where a person stepped in
The author challenged failed suggestions, and a developer friend identified missing database row-level security.
A person approved each step before the agent continued.
The author started startupmap.one while looking for a job at a small European startup. Finding these companies was difficult without existing connections, so they began mapping them manually, starting in Belgium and then the Netherlands. The directory eventually contained more than 2,300 curated European startups, with hiring data, funding stages and locations.
They first built with Lovable and later migrated to Claude Code, despite having no computer science experience or prior coding background. Claude also acted as a tutor while they learned how Supabase, Neon and APIs worked well enough to make product decisions. The author promoted the platform through city subreddit posts and LinkedIn; word of mouth followed, and they were beginning to spend more time on SEO and GEO.
Loading 2,000 logo PNGs made navigation unsatisfying. Several sessions trying clustering approaches suggested by Claude did not fully solve the problem. The author stepped back, proposed a simpler approach that Claude had not suggested, and reports that it worked. Separately, a developer friend noticed database row-level security had not been enabled.
After the first 90 days, the author reported more than 18,000 monthly visitors, average sessions above six minutes and 683 applications started.
Who it's for: Nontechnical directory builders willing to learn their data infrastructure and challenge an agent's proposed solutions.
Prompt
Suggested prompt (written by Agents In Use, not the author's)
Source: Hacker News · denysjw
Frequently asked questions
Did Claude solve the performance problem alone?
No. The author says several Claude-suggested clustering approaches did not fully work. They then thought of a simpler solution themselves and report that it worked.
What oversight issue did a friend find?
A developer friend pointed out that row-level security was not enabled on the database. The post does not say whether or how that setting was subsequently changed.
More details
Remaining steps
- Devised a simpler performance solution after the agent suggestions fell short.
About this account
Claude helped with development and tutored the author on data infrastructure; the author supplied the successful simpler performance approach.
Platform: Hacker News. Attribution: https://news.ycombinator.com/item?id=47573744. Prompt: Suggested (written by Agents In Use, not the author's). Sourced by the Agents In Use pipeline.
Credit: denysjw on Hacker News
Source published 30 Mar 2026
Source checked 14 Oct 2026
Tools and topics
Claude Code · Lovable · Supabase · Neon
Startup directory · Maps · Product development
Editorial completeness: 100/100. Measures documented fields, not agent performance or verified outcomes.