I build products, and the automation that gets them out the door.

What I can do for you ↓
I'm also working on something about AI for small businesses. If that sounds like you, get in touch.
hola@guillermoorellana.es
Services

Currently booked full-time. Open to short advisory work if interesting enough.

How we can work together.

You need another senior pair of hands.
I join your team for a few months and ship with you.

Mobile, backend, payments, and the CI and AI tooling that holds it all together.

Recently: I moved a team's iOS builds off Xcode Cloud and onto GitHub Actions. Checks on every PR, a build every night, a release whenever you tag.
You want someone to look at it with fresh eyes.
A short review with a clear scope.

Architecture, mobile and backend, how you release, and where an AI agent could save your team time.

Recently: I set up bots that open, approve and merge their own pull requests, and a single CI gate for a whole monorepo.
You need someone to lead engineering.
Part-time lead while you hire, or while you grow.

How often you release, code standards, testing, and hiring the people who'll take over.

Recently: Nightly end-to-end tests that create their own test accounts, so nobody has to set them up by hand any more.
Where I've worked

Remote

  • Morse (formerly Sling Money)
  • Guild
  • Qonto+
    • Google Pay Adding your card to Google Pay from inside the app, plus the paperwork for launch approval.
    • Faster, cheaper tests Moved UI tests to Firebase Test Lab: builds 60% faster, fewer flaky runs, 43% lower weekly cost.
    • Automated releases Shipping a new version stopped being a manual checklist.

London

  • Monzo+
    • Salary Sorter Engagement features that helped double the number of people using Monzo as their main account.
    • Smoother sign-up Cut the share of new customers contacting support during sign-up from 7.5% to 2.2%.
    • Face unlock Led the move to the new biometrics APIs so customers could unlock the app with their face.
  • Skyscanner+
    • App start-up Cut Android start-up time by 45% and kept it there, using profiling and telemetry.
    • Build and CI Simplified an over-complicated build setup, CI pipeline and developer workflow.
    • App-wide changes Coordinated regulatory and security changes across tens of squads.
  • Badoo (now Bumble)+
    • Kotlin adoption Led the group that evaluated Kotlin and then brought it into the Android apps.
    • Chappy A new dating app from zero to MVP in a small cross-functional team, with builds 40% faster.
    • API design Helped design the APIs for the whole mobile ecosystem, from the server to every client.
  • Coniq+
    • Coniq Scanner The app the business collected its data with: new architecture, a Material Design facelift, and the UI and redemption logic.
    • Code quality Rebuilt the test suites and set up coverage, linters and static analysis.
    • Phone provisioning Python tools that set up and maintained the company's fleet of phones automatically.

Wrocław

  • Credit Suisse+
    • Research reader Took a cross-platform app for internal and external clients from designs and a proof of concept to release.
    • Mobile framework First app on the bank's new in-house mobile framework, working with its team to shape it.
    • Test automation Automated change-request testing in Python, cutting re-runs by 70%.
About

I studied telecoms engineering and ended up coding. I've lived in Wrocław and London, and came back to Marbella. When I'm not automating something, I'm probably cooking, lifting heavy things or wandering around somewhere new without a map.

Public appearances