We design, ship, and run
consumer apps.

An independent software studio based in Madrid. Two products live, both built and operated end-to-end by the same small team — from mobile clients to AWS infrastructure.

Products

Two products live, more on the way.

Each product is built, run, and supported by the same small team — from mobile and web clients to the production infrastructure beneath.

Live

Champsheep

Pick every World Cup match. Bragging rights only.

A free-to-play social game where football fans pick every match of the tournament, compete with friends in private leagues, and climb global leaderboards — for bragging rights, not money. Built to scale from zero to millions of users during the tournament window, on a Kubernetes-backed AWS footprint.

Infrastructure
Amazon EKS Amazon RDS ElastiCache ALB
Visit champsheep.com
Champsheep prediction interface showing matches and scores
Live

Acutis Firewall

Privacy-first parental control for Android.

A free on-device firewall that blocks adult content, malware, and dangerous sites, with built-in screen-time controls. All filtering happens locally — no user data ever leaves the device.

Platform
On-device Android
Visit acutis.castillo.sh
Acutis Firewall main screen on Android

Infrastructure

Production on AWS.

Champsheep runs on a fully Terraform-managed AWS footprint — lean today, designed to scale into the FIFA World Cup 2026 traffic window.

Compute
Amazon EKS
Managed Kubernetes node groups running the API and web tiers.
Data
Amazon RDS for PostgreSQL
Primary data store with automated backups and Performance Insights enabled.
Cache
Amazon ElastiCache for Redis
Session storage, rate limiting, and hot-path caching across services.
Networking
Application Load Balancer, ACM
TLS termination at the edge with AWS-issued certificates and path-based routing.
Registry & Secrets
Amazon ECR, Secrets Manager
Private image registry and runtime configuration backed by Secrets Manager.
Logs & State
CloudWatch, S3, DynamoDB
Container and audit logs in CloudWatch; Terraform state in S3 with DynamoDB locking.

Where the next investment goes

Areas we plan to expand on AWS as we scale into the World Cup window and add new products:

  • CloudFront at the edge Absorb fixture-time traffic spikes and protect origin during World Cup matches.
  • Lambda for scheduled jobs Replace cron containers with event-driven match-data sync workers.
  • CloudWatch dashboards & alarms Operational visibility and on-call paging as we scale users.

The studio

Small team. Real products.
Long horizons.

Bootstrapped. Two products live. The team that designs them also runs them in production.

The team brings over a decade of engineering experience across distributed systems, security and forensics, and shipping production software in Elixir, TypeScript, and on AWS. We invest deeply in each product we ship rather than spreading thin across many.

Alongside the studio's product work, the founder advises financial institutions in Latin America on cloud migration and IT modernization — including a recent cloud-readiness assessment for Banco de Machala in Ecuador.

Contact

Get in touch.

Investors, partners, and press — we'd love to hear from you.

Headquarters

Madrid, Spain · Delaware, USA