Freelance · Fractional CTO · AI consulting · Madrid & remote

Cayetano Soriano Gallego

AI in production,
on platforms that don't break.

CTO and hands-on architect with 15+ years in tech, 8+ on AWS and 7+ as CTO. I've led two monolith-to-microservices transformations, and today I build LLM features, MCP servers and agentic engineering workflows that run in production.

15+
Years in tech
7+
Years as CTO
2
Monolith → microservices migrations
99.99%
Platform uptime
Built and led engineering at
  • ShareTech
  • Ride On
  • Enolovers
  • Packlink
  • Softonic
  • Kimia

What I build with AI

Not slides: code running in products. Everything below I've built myself over the last year, in client work and in my own products.

LLM features in real products

Claude generating bilingual listings and SEO copy for a marketplace; LLM symptom triage in a digital-health product; OpenAI and Gemini for chat and speech-to-text in a voice assistant. Tool calling and structured outputs, not free-form chat.

Claude APIOpenAIGeminiTool callingSpeech-to-text

MCP servers & agent tooling

MCP servers that let agents read and act on product data safely, from a back-office admin server to a 7-module domain server (medication, schedule, calls, timeline…). Internal tools built on the Claude Agent SDK.

MCPClaude Agent SDKTypeScriptPython

Privacy, tests & cost as defaults

Personal data stripped before any prompt, feature-flag kill switches and switchable EU endpoints for GDPR; LLM calls covered by tests with a fake model transport; the right model per task to keep cost in check; Sentry monitoring like any other service.

GDPRPII redactionFeature flagsTestingSentry

Agentic engineering for teams

Claude Code across a dozen repos with project rules (CLAUDE.md) enforced in CI, AI agents in CI/CD and automated dependency updates. As CTO, I introduced LLM-assisted workflows into the engineering process.

Claude CodeCI/CDDependabotCursor

Three things I do well

Architecture that scales

Two legacy monoliths (Clojure, PHP) decomposed into 20+ containerized microservices on AWS ECS, with Terraform-first infrastructure and 99.99% uptime in production.

Teams that deliver

Built and scaled engineering organizations as CTO at two companies: OKRs, cross-functional squads, on-call culture, and developer experience as a first-class concern.

The business side of tech

Vendor and partner contracts (Telefónica), technical due diligence with investors, city-council stakeholders in four cities, budgets and SLAs. I speak engineering and board.

20+
Microservices in production
30%
AWS cost reduction
0 s
Deploy downtime (Packlink)
10s → <1s
App load time (Enolovers)

Problems I've solved

Context → what I did → measurable outcome. The pattern repeats across companies: inherit something fragile, make it boring and reliable, then let the team move fast on top of it.

Enolovers · 2026 · Freelance

AI that writes the first draft of every listing

Context
Wine-experience marketplace: wineries sent rough notes, and turning them into bilingual, SEO-ready listings was slow manual work.
Action
Claude-powered generators (Anthropic SDK) that turn a winery's notes into an ES/EN title, description and price, plus an SEO copywriter and an onboarding drafter, tested against a fake model transport. An MCP admin server so agents can operate the back office.
Result
From a blank page to a reviewable bilingual draft; AI features ship through the same CI, tests and monitoring as the rest of the API.
Claude APIMCPPHP / SymfonyTypeScriptCI/CD
Digital health · 2026 · Own product, in development

LLMs where privacy is not optional

Context
Care platform for older adults and their families: symptom triage and a voice companion, on health data covered by GDPR.
Action
Symptom triage on Claude with personal data stripped before every prompt and feature-flag kill switches; voice companion with OpenAI speech-to-text and a switchable EU endpoint; an MCP server with 7 tool modules (medication, schedule, clinical, calls, timeline…).
Result
AI designed for regulated health data from day one, without slowing product iteration.
Claude APIOpenAIMCPGDPRTypeScript
Ride On · 2018–2019

From a Clojure monolith to 20+ microservices on AWS

Context
City-scale eSharing mobility platform blocked by a legacy monolith: slow releases, single points of failure.
Action
Designed and led the full re-architecture: 20+ containerized services on ECS, 100% of infrastructure in Terraform, CI/CD with Jenkins, observability with Sentry + PagerDuty.
Result
Critical bottlenecks eliminated; platform able to scale to city-wide operations. Promoted to CTO.
ECSTerraformJenkinsSentry
Enolovers · 2026 · Freelance

App load time from 10 s to under 1 s

Context
Consumer app growing fast with a small team: 10-second loads, scalability pain, slow releases, dependency drift and no clear security baseline.
Action
Resource loading optimization, lazy vs eager data loading, DB indexes, Redis caching and rate limiting; CI/CD with AI agents, automated dependency updates and a test harness; security best practices; Terraform for all infrastructure; Sentry, monitoring, analytics and per-call metrics.
Result
App load time cut from ~10 s to under 1 s; predictable releases; infrastructure reproducible and fully monitored.
PerformanceCI/CDAI agentsRedisTerraformSentry
More case studies
Ride On · 2019–2023

Cutting infrastructure cost while raising reliability

Context
Growing fleet and traffic; AWS bill scaling faster than revenue; investors requiring technical due diligence.
Action
Optimized container orchestration on ECS, introduced event-driven architecture on Kinesis, set OKRs for the tech org, owned security and uptime end to end.
Result
~30% lower AWS spend, 99.99% uptime, and due diligence passed with investors.
ECSKinesis
Packlink · 2015–2017

Zero-downtime migration to a polyglot architecture

Context
High-traffic e-commerce shipping platform (Packlink Pro, eBay integration) on a monolithic PHP codebase.
Action
Drove the migration to Java/Scala/Python microservices with RabbitMQ event patterns and Cassandra/Redis storage.
Result
Zero-downtime deployments across peak e-commerce operations.
JavaScalaRabbitMQCassandra

Who I am

I'm a CTO who still reads pull requests. Over 15+ years I've gone from web developer to architect to running technology for two companies, and I've kept one rule: own the whole stack, from the Terraform module to the on-call rotation to the roadmap conversation with the board.

I've taken companies from legacy monoliths to cloud-native microservices on AWS, and I've done the unglamorous work that makes that stick: CI/CD, observability, cost control, security, and technical due diligence with investors.

Today I'm focused on AI in production: LLM features, MCP servers, agentic engineering workflows and the guardrails around them (privacy, tests, cost, observability), built with the same discipline as any other backend service. I speak Spanish and English and work equally well in either.

Location Remote, or on-site in Madrid, Spain (CET)
Languages Spanish (native) · English (professional)

Experience

Independent Apr 2026 — Present
Fractional CTO, Architect & AI Engineer
Remote
  • Fractional CTO and hands-on architect/developer for early-stage companies: technical strategy, architecture reviews, cloud and delivery setup.
  • Enolovers (client): cut app load time from ~10 s to under 1 s (resource loading, lazy vs eager data, DB indexes, Redis caching, rate limiting); Claude-powered bilingual content generation and an MCP admin server; CI/CD with AI agents, automated dependency updates and a test harness; security best practices; infrastructure in Terraform; Sentry, monitoring, analytics and per-call metrics.
  • Own digital-health product (in development): LLM symptom triage with personal-data stripping, a voice companion with speech-to-text, and an MCP server with 7 tool modules.
  • Deep-dive training in security, AI/LLM systems, software architecture and blockchain, applied directly to client work.
Fractional CTOAWSTerraformRedisCI/CDAI / LLMsSecurityBlockchain
ShareTech Mar 2023 — Apr 2026
Chief Technology Officer
Madrid, Spain
  • Owned the technology vision and roadmap; final say on cloud architecture, build-vs-buy and platform investments.
  • Led cross-functional engineering squads; set standards for microservices governance, reliability and developer experience.
  • Hands-on across infrastructure automation (Terraform, ECS), AWS cost optimization and on-call/observability with Sentry + PagerDuty.
  • Vendor and partner contracts (M2M and cybersecurity integrations with Telefónica); technical counterpart for Pamplona City Council.
  • Operations & logistics tooling: metrics, SLAs, reporting dashboards and cost optimization.
  • End-to-end observability: OpenTelemetry instrumentation, Datadog/New Relic, CloudWatch, Kibana, Sentry and PagerDuty on-call.
  • Hands-on backend development; introduced LLM-assisted workflows into the engineering process.
AWSTerraform DockerSpring BootSentryPagerDutyM2M / IoTOpenTelemetryDatadogKibanaSecurity
Ride On 2019 — Mar 2023
Chief Technology Officer
Madrid, Spain
  • Promoted from Architect to CTO to own the full technology strategy of the eSharing mobility platform (remote since 2020).
  • Scaled the engineering organization and introduced OKRs for the tech department.
  • Drove event-driven architecture on AWS Kinesis; optimized container orchestration on ECS, cutting infrastructure cost ~30%.
  • Directly accountable for uptime (99.99%), security and technical due diligence with investors.
  • Vendor and partner contracts (M2M and cybersecurity with Telefónica); technical counterpart for city councils in Miami, Dundee, Leicester and Pamplona.
  • Operations & logistics: internal tooling, metrics, SLAs and reporting dashboards.
  • End-to-end observability: instrumented every service with OpenTracing / OpenTelemetry (distributed tracing), structured metrics and alerting (New Relic, Datadog, CloudWatch, Kibana, Sentry, PagerDuty) — from request to database.
AWSTerraformKinesis DockerOpenTracingOpenTelemetryDatadogNew RelicCloudWatchKibanaPagerDuty
Ride On 2018 — 2019
Software Architect
Madrid, Spain
  • Led the complete platform re-architecture: legacy Clojure monolith → 20+ containerized microservices on AWS ECS.
  • Authored the entire Infrastructure-as-Code layer in Terraform; automated CI/CD with Jenkins, images with Ansible + Packer.
  • Established observability with Sentry and PagerDuty; removed the bottlenecks blocking city-wide scale.
ECSTerraformDynamoDBElasticsearch JenkinsAnsiblePackerClojureSentry
Kimia 2017
Software Architect
Madrid, Spain
  • Designed and delivered high-throughput backend services in Go, backed by Redis and Elasticsearch.
  • Built real-time monitoring and alerting pipelines that improved incident response times and reliability.
RedisElasticsearchMonitoringAlertingHigh availability
Packlink 2015 — 2017
Backend Engineer
Madrid, Spain
  • Key contributor to the Packlink Pro and eBay shipping integration backend.
  • Drove the migration from a PHP monolith to polyglot microservices (Java, Scala, Python) with RabbitMQ, Cassandra and Redis.
  • Zero-downtime deployments across high-traffic e-commerce operations.
  • Platform monitoring and on-call: Kibana/Elasticsearch dashboards, CloudWatch, Sentry and PagerDuty for a high-availability product.
PHPJavaScalaPythonSpring Boot CassandraMongoDBRedisDockerRabbitMQKibanaSentryPagerDuty
Betabeers 2012 — 2015
Community Organizer & Speaker
Barcelona & Cádiz, Spain
  • Co-founded and led the Betabeers chapters in Cádiz and Barcelona: monthly meetups for 50–100+ developers and founders.
  • Built a local tech community connecting startups, engineers and investors.
Community leadershipPublic speakingStartups
Softonic 2013 — 2014
Backend Engineer
Barcelona, Spain
  • Backend for the Softonic Downloader, serving millions of daily downloads.
  • Data pipelines on the Hadoop ecosystem (Hive, Oozie); TDD with PHPUnit.
PHPMySQLHadoopHiveRabbitMQTDD
Crononauta 2012 — 2013
Web Developer
Spain
  • Built and maintained content-driven web applications with PHP and Drupal 7, from requirements to production.
PHPDrupal 7
Soluciones DTV 2011
Team Lead
Spain
  • First leadership role: managed a development team shipping a social networking platform from scratch, from technical design to launch.
Team leadershipProduct development

Skills & technologies

AI, agents & LLMs

LLM features, MCP servers and agentic workflows shipped in real products, with privacy, tests and observability built in.

  • Claude / Anthropic API
  • OpenAI API
  • Gemini API
  • MCP (Model Context Protocol)
  • Claude Agent SDK
  • AI agents
  • Tool calling
  • Structured outputs
  • Prompt engineering
  • Speech-to-text (Whisper)
  • PII redaction / GDPR
  • Claude Code
  • Cursor
  • GitHub Copilot
  • Blockchain / Smart contracts

Cloud & infrastructure

8+ years designing and running AWS platforms: containers on ECS, Terraform-first infrastructure, event streaming.

  • AWS
  • Terraform
  • ECS
  • Serverless
  • Kong
  • Kinesis
  • SNS / SQS

Backend

15+ years across PHP, Java/Spring Boot, Python, Scala and TypeScript; from monoliths to polyglot microservices.

  • Java / Spring Boot
  • TypeScript / Node.js
  • Python
  • Scala
  • PHP

Data & storage

Choosing and operating the right store per workload: key-value, search, cache, wide-column and relational.

  • DynamoDB
  • Elasticsearch
  • MongoDB
  • MySQL
  • Redis / ElastiCache
  • Cassandra
  • Hadoop / Hive

DevOps, CI/CD & observability

CI/CD pipelines, immutable images, on-call and observability; reliability as an engineering practice, not a team.

  • Docker
  • Jenkins
  • Ansible
  • Packer
  • Consul
  • OpenTelemetry / OpenTracing
  • Distributed tracing
  • Datadog
  • New Relic
  • CloudWatch
  • Kibana
  • Sentry
  • PagerDuty
  • RabbitMQ
  • Security hardening

Leadership

7+ years as CTO: roadmap, hiring, OKRs, vendor contracts, due diligence, budgets and city-council stakeholders.

  • Tech strategy & roadmap
  • OKRs
  • Hiring & team scaling
  • Technical due diligence
  • Cost management
  • Security & incident response

Education & certifications

Universidad de Cádiz

Computer Systems Engineering

2007 — 2014

Megathon W8 Cádiz

Hackathon award

Earlier: Zend Certified PHP Engineer, MongoDB Certified DBA & Developer, Oracle MySQL Developer.

Want to talk architecture, teams or AI in production?

Tell me what you're building. The first 30-minute call is free, and I reply to every serious message within 48 hours.

hello@cayetano.dev