Haired CV

Inspiration

I spent years on the recruiting side before building this reviewing thousands of resumes, watching qualified people get filtered out by ATS systems before anyone read their name. The gap between "this person is great" and "this person never got a callback" usually came down to something stupid: they used the word "led" and the job posting said "managed." Same thing. Different word. Filtered out. Then I moved to Barcelona and started applying for jobs myself in a market that works completely differently from what I was used to. Photos on CVs. A4 format. Two pages instead of one. Every piece of resume advice online was written for the US market, and none of it applied. That's when it clicked there wasn't a single AI resume tool built for how hiring actually works outside the US. So I built one.

What it does

HAIRED analyzes your CV against any job description and tells you exactly which keywords you're missing the ones the ATS is actually scanning for. It rewrites your CV to close those gaps without inventing experience you don't have. It also scores your LinkedIn profile against the same criteria recruiters use, because most resume tools completely ignore the fact that recruiters check both. It's built specifically for European and LATAM job markets proper A4 formatting, photo guidelines by country, full Spanish language support, and ATS logic tuned for non-US hiring systems. It's also one of the only tools in this space with a real native iOS app instead of a mobile browser wrapper.

How I built it

The core is a Python backend that runs CVs through an ATS simulation layer parsing structure, extracting keywords, and scoring against a target job description. On top of that sits an OpenAI-powered rewriting layer that takes the gaps the simulation finds and suggests rewrites that stay true to the person's actual experience. The web app is Next.js, the database is Supabase, and the iOS app is built with React Native / Expo so I could ship to both platforms without maintaining two completely separate codebases. I built all of it solo, which meant a lot of decisions came down to "what can one person actually maintain" rather than "what's the most elegant architecture."

Challenges I ran into

Getting the ATS simulation to actually behave like real-world ATS systems was the hardest part by far. There's no public documentation for how Greenhouse, Workday, or Taleo parse resumes I had to reverse-engineer behavior by testing hundreds of real CVs and cross-referencing actual rejection patterns. The second challenge was language. Building genuinely good Spanish-language CV optimization isn't just translation Spanish job postings use different conventions, different keyword density expectations, and recruiters in different countries weight sections differently. Getting that nuance right took way longer than I expected. And honestly doing this solo while also handling support, marketing, and everything else has been its own challenge. There were weeks where shipping a feature meant three other things didn't get done.

Accomplishments that I'm proud of

We've now processed over 10,000 resumes through the ATS engine, and users who complete the full optimization flow see a 36% increase in interview callbacks on average. That number is what keeps me building this it's not abstract, it's people actually getting interviews they weren't getting before.

I'm also proud that we built something genuinely different from the fifteen other AI resume tools out there instead of just cloning Rezi with a different logo. The European and LATAM focus wasn't an afterthought it's the entire reason this exists.

What I learned

That the hardest part of building an AI product isn't the AI it's the domain knowledge underneath it. Anyone can wrap GPT in a nice UI. Understanding why a specific ATS rejects a specific resume format took way more research than the actual AI integration did. I also learned that solo founders underestimate distribution constantly. I spent the first few months almost entirely on product and barely touched marketing in hindsight, I should have started talking to users and building in public much earlier.

What's next for Haired CV

Expanding template variety it's currently our weakest area compared to more established tools. Deeper salary benchmarking by role and country. And I'm working on extending ATS coverage to more European markets beyond Spain, Germany, and France. Longer term, I want HAIRED to be the default tool for anyone job hunting outside the US not an alternative to the American tools, but the obvious choice if you're applying in a market they were never built for.

Built With

• expo.io
• next