Jesús Roncal

AI & Backend · Milan

Open to AI Engineer roles · EU

Open to AI Engineer roles · EU

I ship LLM systems
that survive production.

Eight years in backend; the last four shipping multi-agent, RAG and eval pipelines to real users.

Senior Software Engineer, AI & Backend. Eight years building backend systems — the last four shipping multi-agent, RAG and eval pipelines to real users. Measured, grounded, cost-aware. Based in Milan.

Jesús Roncal smiling, in front of a brick archway on a sunny day

NowAI Engineer · Intercorp

2025 – 2026Tech Lead · MindFortress

Milan, IT · ES / EN / IT
Esc

    Selected work

    Four problems, and what changed

    How I approached each one, in the order it happened. Every case reads in about ninety seconds.

    01 · Intercorp · AI Engineer

    Evals before vibes: fixing a prompt that drifted

    Before: 45.6%. After: 100%.

    LLM-as-judge fixtures across 5 dimensions and 19 items turned prompt changes into a measured release gate. Structural conformance: 45.6% in production before the fix, 8 of 8 test fixtures after it.

    • Gemini 2.5 Pro
    • Spring AI
    • LLM-as-judge
    Read the case

    02 · MindFortress · Tech Lead

    Finding the AI spend nobody could explain

    Before: ~$16/day. After: guarded.

    A spend bucket with no owner was costing about $16 a day. I traced it to a stale staging worker running against the production database, shipped a guard in the code and split the production and staging credentials.

    • Python
    • Railway
    • Root-cause analysis
    Read the case
    Two more cases

    Open source

    Code you can actually read

    Client work stays under NDA. These are public, small on purpose, and each one is about a single idea.

    Experience

    Eight years, one directionEight years, three continents, one direction

    From PHP back offices in Lima to leading AI products for US startups — always on distributed teams across the US, EU and LATAM.

    1. 2024 — nowAI EngineerIntercorp · Innova LATAMProduction LLM system generating curriculum-aligned lesson plans for 3 countries.Peru · remote
    2. 2025 — 2026Technical Lead, AI ProductsMindFortressCode review and release gating for Freya and Reeve; the team’s AI-assisted delivery system.USA · remote
    3. 2022 — 2024Backend & AI EngineerWordboxLLM content pipelines for 500K+ learners; Python → Go rewrite, −40% latency.MX / UK · remote
    4. 2023 — 2024Backend DeveloperAccelOneVideo platform backend: large-file pipelines on SQS, Elasticsearch search.USA · remote
    5. 2021 — 2022Backend Developer, freelanceIndra · Pretty TechnicalAPIs serving ML models at 95% coverage; Go services for fintech and genomics.PE / NL
    6. 2020 — 2022Backend DeveloperRed Científica PeruanaInternationalised a hosting platform serving 11,000+ businesses.Lima
    7. 2017 — 2020Software EngineerCodriseFrom L3 support to shipping Laravel and CodeIgniter APIs.Lima
    8. 2017 — 2022Backend & Software EngineerIndra · RCP · Codrise

    How I work

    Three rules I don’t break

    1. Evals before vibesA prompt change ships when a fixture set says it is better — not when it reads better.
    2. No threshold is a guessEvery limit in a system I own has a measurement next to it, and a note on what it costs.
    3. Cost is a featureTokens, latency and dollars per request are on the dashboard from day one, and reported to whoever pays.

    Let’s build something
    that holds up.

    Open to AI Engineer, Senior Backend and Tech Lead roles across the EU.

    Open to AI Engineer, Senior Backend and Tech Lead roles across the EU — remote, or on-site in Milan.

    Download CVEmail me