I find what's slowing your team down, and fix that first.
Usually it's a team without a lead, a legacy stack that's hard to change, a backend that might not hold at peak, or a release process nobody trusts. I'm Mario Kranjec, a senior backend engineer and contract tech lead. I join part-time or for a defined project, and work in your repo until your team can carry on without me.
Book a call30 minutes, free. No prep needed.
- 100k
- URLs migrated to Next.js for InYourPocket, with search rankings up after launch
- 2.45M
- requests per second at peak on a top global sportswear brand's drop platform
- 7
- engineers led as acting team lead at CargoX
What are you dealing with?
- Your team needs a lead, but not a full-time hire yet.Contract tech leadI join 2–3 days a week to run planning, set architecture and code standards, and mentor the team, until you hire a lead or no longer need one.
- The old stack is slowing you down, but your traffic depends on it.Legacy migrations without losing SEOMove from a legacy PHP stack to a modern one section by section, behind redirects and monitoring, so search rankings hold.
- Peak traffic is coming, and you're not sure the backend will hold.Scale and performanceFind the bottlenecks before your users do: service-to-service communication, caching, databases and load testing for launch-day traffic.
- Shipping is slow, even though everyone's working hard.Developer experience and deliveryFaster local setup, CI/CD your team trusts, end-to-end tests that catch regressions, and code standards that enforce themselves.
Case studies
- 100kURLs migrated, search rankings up after launch
Moving a 100+ city travel guide from Symfony to Next.js without losing search traffic
- 2.45Mrequests per second at peak · 50 Gbps · 14+ markets
Product drops that held at peak
How we can work together
- Fractional
- 2–3 days a week as part of your team, for as long as it's useful. Often that's until you hire a permanent lead.
- Fixed-scope project
- One defined outcome, such as a migration, a performance push or a delivery setup, with scope and timeline agreed upfront.
Based in Slovenia. Remote-first, working in EU time zones (CET). On-site visits by arrangement.
I’ve spent more than ten years building production systems. Most recently I was tech lead on InYourPocket’s move from Symfony to Next.js, and acting team lead for seven engineers at CargoX. I work hands-on: in your standups and your planning as well as the code.
Outside client work I co-organise Spletne urice Maribor, Slovenia’s longest-running tech meetup.
Not sure which of these fits?
That's what the intro call is for. Tell me what's going on, and I'll tell you honestly whether I'm the right person to help. If it's a fit, I send a short written proposal, and the first week is an assessment of your code and team.