Discovery
Process mapping, SaaS vs custom decision, functional definition.
SS-06 · Custom development
Custom development
We build software when your operations do not fit a SaaS. Microservices and DevOps when the problem justifies it. Fortnightly sprints with a live demo.
Not every process has a SaaS, and not every SaaS fits the real process. When an off-the-shelf tool falls short — because the flow is highly specific, because integration costs more than development, or because data cannot leave the client's environment — we build custom.
Current stack: TypeScript, Python, Go, Rust depending on the problem; React/Next/Nuxt/Svelte on the front end; Node/FastAPI/Spring/.NET on the back end; Postgres as the default database. Microservices only when the team and operations justify it; modular monolith when they do not.
What we deliver is a production system with documented code, tests, automated deployment, observability, and handover to the client's team. Not closed projects with opaque code.
L1Edge & CDN
- Cloudflare
- Vercel Edge
- WAF
L2Front-end
- Next.js
- Nuxt
- Svelte
- React Native
L3API & services
- Node · Fastify
- FastAPI
- Go
- .NET 8
L4Data
- Postgres
- ClickHouse
- Redis
- S3
L5Platform
- Kubernetes
- Terraform
- GitHub Actions
- Grafana
The Custom development process.
The process · four stagesTechnical design
Architecture, stack, data model, integrations.
Build
Fortnightly sprints with a live demo.
Handover
Documented code, tests, automated deployment.
What is included
What Custom development includes.
The operational detail: what we deliver as part of the engagement and what we keep active afterwards.
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Web and internal applications
Processes that do not fit a SaaS.
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Mobile and hybrid
React Native, Flutter, native Swift/Kotlin.
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Microservices when applicable
Not by default. Modular monolith when it works.
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DevOps and CI/CD
GitHub Actions, Docker, Kubernetes, Terraform.
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Operational documentation
What your team needs to operate.
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Full handover
Code, secrets, infra, runbooks. No black box.
Summum cluster
How it intersects with related services.
What is built runs in production. It integrates with cloud, security, and data services.
Frequently asked questions about Custom development.
Fixed scope or T&M?
Fixed scope when the scope is clear. T&M when there is iterative discovery.
What stack?
TS, Python, Go or Rust depending on the problem. React/Next/Nuxt on the front end; Node/FastAPI/Spring/.NET on the back end.
Is the code ours?
Yes. Repository in your organisation from day one.
Operations · open log
This is what a deployment sounds like.
What you see when a release goes to production. No surprises, no manual clicks.
→ summum deploy --env prod --service api --tag v2.14.0 checking signing key… ok ✓ tests pasados (1.241/1.241) en 3m 41s ✓ build firmado · sha 9f3a82c ✓ canary 5% · 4m · p99 124ms · errores 0 ✓ rollout completado en 4m 12s → summum status api.cliente.com status healthy uptime 47d 09h 22m replicas 3/3 p50 / p95 / p99 38ms / 89ms / 124ms error rate (1h) 0.00%
Field notebook
Field logbook.
Post-mortems and technical notes from real projects.
2026-04 Fashion eCom · LCP
From 1.8s to 340ms in 6 weeks
Images converted to AVIF, n+1 query fixed, CDN cache. Conversion increased 22% in the quarter.
2026-02 Industrial · custom ERP
Quote cycle 11 days → 38h
.NET module on top of CRM + legacy ERP. We kept the accounting SaaS.
2025-12 Public sector
28k users/day migrated to cloud with no downtime
Strangler-fig pattern over 22 weeks. RTO 12 min on game day.