Backend & data
We build APIs and integrations, untangle data models and find slow queries. The next engineer should be able to pick up where we left off.
HILLS Lab
We build backend systems and software products.
HILLS Lab is a founder-led engineering studio in Split. We build and improve backend systems, product workflows, and operational infrastructure for teams that need ownership, speed, and dependable delivery.
Focus
We find what's holding things up.
Sometimes it's a slow query. Sometimes it's the integration nobody wants to touch, or a feature that keeps missing the release.
We read the code, talk to the team and trace the problem to its cause. Then we agree on the scope and see the change through testing and release.
Use cases
Where we bring the most value.
From brief to release
We clarify the brief, cut the excess and ship a useful first release. What we learn from users shapes the work that follows.
AI in the dev workflow
We give agents context, limit their access and review the result. AI speeds up the work; we remain responsible for the change.
After the deploy
We prepare monitoring, migrations and rollback. When something breaks, the team needs to know what happened and how to get the system back.
Recommendations
Proof from teams we have built with.
Povio, ReneVerse, and Tilt are HILLS Lab work. The other recommendations show the wider engineering track record behind HILLS Lab.
HILLS Lab engagement Open, professional, transparent in communication, and reliable on every agreed scope.
HILLS Lab engagement A top-tier engineer who made next-level impact across core Web2/Web3 services and real-time ad targeting infrastructure.
HILLS Lab engagement Multiple people have called out the quality and speed of Hrvoje's work across several projects.
Wider engineering track record
Ericsson Nikola Tesla Founder track record
Curious, proactive, and willing to take responsibility beyond his role early in his career.
Profico Founder track record
Someone we could truly rely on, not afraid to take responsibility and push new initiatives forward.
Rimac Automobili Founder track record
An exceptionally capable engineer whose code was built to last in a highly challenging hypercar telemetry and OTA domain.
Thesis
Tools change. Engineering judgment compounds.
The highest-value part of senior engineering is not the amount of code produced. It is finding the real constraint, explaining the trade-off clearly, and delivering a system the team can safely continue to evolve.
Engagement model
A small pilot before a large promise.
Discovery
One conversation and a short review of the product, domain, team, existing system, and the outcome that matters.
Problem and boundaries
We map the domain, existing system, ownership, risks, and the real constraint behind one concrete workflow.
Delivery
We build the smallest serious part of the solution that can be tested with real data, users, and operational conditions.
Release and handoff
You get a verified change, documented decisions, and a clear next step for handoff, continued implementation, or ongoing support.
Six checks before the change
The same questions apply to code, a migration, an AI workflow, or a production operation. Speed only matters when the change stays understandable and verifiable.
Source
Which repo, ticket, incident, document, or decision supports the claim.
Freshness
Whether the information is still current or a newer record has replaced it.
Permission
Whether this context is allowed for this team, tool, actor, and task.
Risk
What could break production, leak data, or lead the agent to a wrong conclusion.
Change
What changed since the last run, deploy, incident, or recorded decision.
Trace
Whether a person can replay the path: sources, permissions, decision, and result.
PLAYGRND PLAYGRND proof point
Product, backend, and operations in one ownership loop.
We build PLAYGRND as a public record for amateur football: SSR web, a private Go API, Postgres/Redis, WhatsApp magic links, claim/correction loops, admin review, and recomputable season aggregates. It shows how HILLS works when product, architecture, data, release, and operations share one owner.
Applied context research / Memoato
Trustworthy memory, implemented as a product.
Memoato preserves raw entries, separates reviewed facts from inferences, records corrections, returns evidence with recall, and limits API/MCP keys to logging, recall, or both. Personal memory is the first workspace; the architecture is our practical base for future permission-aware context.
Community work / Pro bono
A new website for a club built around its community.
We designed and built NK Prugovo's website pro bono, giving the club one clear place for its story, youth academy, media coverage, partners, and contact information.
For local software teams
Local companies often do not need another vendor or generic demo. They need a senior engineer who can understand the domain quickly, work with the existing team, and own a concrete outcome.
Notes
Working notes from practice.
Short notes on backend decisions, product workflows, operations, and the safe use of modern AI tooling in real software work.
Read notes