Software, business and AI consulting

Technical judgement to decide what to do before you build.

I analyse your problem and help you decide what to do, how to do it and where to start.

See how I work ↓

01Services

What I can do for you

Four concrete problems where business and technology need to move forward together.

Not sure your case fits? Tell me in two lines.

02Method

How I work

Five steps, and you don't have to climb them all.

first session

The first conversation

Understanding the problem and scoping it. No deliverables.

fixed price

The map

Your knowledge, ordered and navigable.

hourly

Judgement

What is dead weight, what to redirect, what will get expensive.

scoped

Test

A prototype that proves or rules out that something fits.

budget per phase

Implementation

In phases, each with its own scope and price.

Pricing agreed in the first conversation · 50% up front, 50% on delivery · no maintenance.

The first step is half an hour of conversation. No strings attached.

03Cases

What I have built

Discover my products, open-source projects, client work and research.

Products

zetesis rag — Búsqueda y agentes sobre tu propia documentación

graphmarks — Tus marcadores, como un mapa

sebastian — Voz bidireccional sobre hardware propio: el altavoz sobre la mesa, con el anillo de luz encendido

Projects

Konect

Konect: audio transcription and analysis

ProductKonectTranscription

Homelab

Building a homelab from scratch: the big picture - Homelab (01/06)

Case studyHomelabProxmox

Escohotado

Antonio Escohotado's legacy, explorable with AI

Case studyEscohotadoRAG

CERN's IT governance graph, with its nodes and relations

CERN graph

CERN's IT governance, navigable as a knowledge graph.

CERNQuartzKnowledge graph

Open the graph

CERNphone

CERNphone: telephony for more than 5,000 users

ProductCERNphoneTelephony

Keycloak

Centralized identity management with Keycloak

LabKeycloakRBAC

Naiz Fit

Naiz Fit: configurable testing campaigns

Case studyNaiz FitProduct

Zetesis Portal

Zetesis Portal and PayloadAgents: how we built our SaaS

ProductZetesis PortalPayloadAgents

El panel del optimizador fiscal foral: el ahorro identificado del ejercicio en grande, la barra del crédito vitalicio de vivienda agotado a 36.000 €, y el desglose por vivienda, EPSV e inversiones, con el pie que recuerda que todo es una proyección del mismo log de eventos y que la herramienta es orientativa.

Simulador de la Renta

A simulator for Bizkaia's foral income tax

LabEvent sourcingTaxation

Las dos mitades del montaje, separadas por una diagonal. A la izquierda, sobre fondo oscuro, la gráfica de coste por modelo de Langfuse a lo largo de tres meses, con el gasto acumulado del periodo. A la derecha, la tabla de la pasarela: cuatro alias estables —chat-estandar, chat-premium, razonador y economico— apuntando a modelos de cuatro proveedores distintos, cada uno con su coste de entrada y de salida por millón de tokens.

LLMOps

LLMOps on your own cluster with LiteLLM, Langfuse, and ArgoCD

LabLLMOpsGitOps

Postiz

Postiz: scheduling social media posts from your own server

LabHomelabKubernetes

Harbor

A Harbor of our own for the cluster's images and charts

LabHarborGitOps

Go to the blog →

Collaborations

Facing a similar problem?

04About me

Rubén García Hernando

Software architect and researcher

I could not make sense of this work without research. After three years at CERN, back in Bilbao I decided to work on my own and keep researching and learning. I believe entrepreneurship is the ultimate professional challenge — and, at the same time, an expression of creativity and a claim to freedom.

Zetesis comes from the Greek ζήτησις, inquiry: find the cause before proposing the solution.

Learn more

2023 — today

Zetesis

Founder. My own platform, in production.

2023 — 2024

Naiz Fit

iOS and Android apps used at scale.

2019 — 2022

CERN

Internal telephony: 30,000 calls a day.

2017 — 2019

LIN3S

From developer to software architect.

Complex IT problems

Unblock problems caught between business and technology

The problem

What the business needs and what technology offers no longer fit. The gap grows until it becomes a problem neither side can solve on its own.

How I help

I find where the fit has broken down and help align priorities, architecture and capabilities. When the gap is in the team’s skills, I train and support them so they can deliver and sustain the solution.

When every explanation contains some truth

Business sees technology delivering too slowly. Technology sees constantly changing priorities. Leadership sees missing ownership, while the team receives dates without control over scope. Choosing one version too early produces an incomplete solution.

The discussion also often starts with an answer — migrate, hire, rewrite or introduce AI — before anyone agrees on the outcome that needs to change. A technically sound proposal may still miss the business priority.

The human factor is part of the system

My approach is inspired by Javier G. Recuenco’s personotecnia: in a complex problem, people’s capabilities, motivations, relationships and behaviour are a central source of complexity.

A deadline may protect a commercial commitment unknown to technology. Resistance may come from a previous delivery that caused months of incidents. Understanding what each person knows and is trying to protect prevents elegant solutions that nobody will execute or maintain.

The goal is not to make business and technology think alike. It is to get them working on the same problem again.

Reconstruct before proposing

I listen to the relevant perspectives, review earlier decisions and separate facts, interpretations and hypotheses. We then examine four dimensions that are usually tangled together.

The outcome the business actually needs.
What technology can offer and which constraints are real.
The knowledge, time and autonomy available to the team.
The trade-off or decision nobody has yet made explicit.

Turn conflict into decisions

I am not a messenger and I do not soften constraints. I translate broad goals into observable outcomes, technical limits into business consequences, proposals into comparable options and agreements into an owned plan.

The answer may be to change the architecture, reduce scope, alter a priority, remove a feature or stop an initiative. Technology is part of the answer, but cannot decide it in isolation from the organisation.

Train the team when the solution requires it

If the blocker is capability, training becomes part of the real work. I design sessions, hands-on support and documentation around the tools and decisions the team will need to sustain without outside help.

Training is also a reality check: if maintaining the solution requires turning the entire organisation into specialists, we should first ask whether that complexity is justified.

What changes

The problem stops bouncing and becomes a shared decision

01A diagnosis that combines business, technology and the human factor.
02Facts, constraints and hypotheses clearly separated.
03Comparable options with visible costs, risks and trade-offs.
04An executable decision with clear scope and ownership.
05Support and training where the team needs new capabilities.

Understand the approach

IT consulting and governance Javier G. Recuenco: personotecnia and complex problems

Stop handing the same problem back and forth

If the issue has survived several meetings without progress, a first conversation can help identify the decision that is still missing.

Software, business and AI consulting

What I can do for you

Standardise how your team builds software with AI

Put your company knowledge to work with AI

Turn your prototype into a sellable product

Unblock problems caught between business and technology

Standardise how your team builds software with AI

Put your company knowledge to work with AI

Turn your prototype into a sellable product

Unblock problems caught between business and technology

Standardise how your team builds software with AI

Put your company knowledge to work with AI

Turn your prototype into a sellable product

Unblock problems caught between business and technology

How I work

The first conversation

The map

Judgement

Test

Implementation

What I have built

Products

Zetesis RAG

Graphmarks

Sebastian

Projects

Konect

Homelab

Escohotado

CERN graph

CERNphone

Keycloak

Naiz Fit

Zetesis Portal

Simulador de la Renta

LLMOps

Postiz

Harbor

Collaborations

Rubén García Hernando

Zetesis

Naiz Fit

CERN

LIN3S