API design
REST, GraphQL or tRPC — the choice follows the consumer, not developer pride.
- OpenAPI specs as contract baseline
- Versioning & deprecation plan
- Rate-limit & quota strategy
Backend Development
Back-ends that survive both load and audits
APIs, event pipelines and data models for regulated industries — observable from day one, deployable any hour.
Disciplines
Four pillars of a maintainable backend platform
We separate concerns cleanly, document every assumption, and ship telemetry before the first feature goes live.
Data models
Postgres-first with a clear migration history. Event sourcing when audit obligations require it.
- ACID guarantees as the default
- Read replicas for reporting
- Time-travel via logical decoding
Observability
OpenTelemetry traces, structured logs, Prometheus metrics — no backend ships without all three.
- p50 / p95 / p99 as SLOs
- Distributed traces in Tempo
- Alerts on symptom, not cause
Security & compliance
mTLS between services, immutable audit logs, GDPR and ISO-27001-ready.
- Secret rotation automated
- Threat modeling per service
- PII encryption at the column level
Default stack
What we start with on day one
These defaults have proven themselves in 70+ production back-ends. Deviations are possible — but they need a reason.
LayerPickWhy this
RuntimeNode 24 · Bun · GoNode for API-first teams, Go for high-load services. Bun where edge cold-start matters.
DatabasePostgres 18We take "Postgres is enough" seriously. Other stores only when there is a documented reason.
CacheRedis · KeyDBDistributed locks, session state, rate limits — Redis is the unspectacular standard here.
Queuepg-boss · Kafkapg-boss up to 10k events/min, Kafka above that. No premature streaming architecture.
HostingAWS · Hetzner · K8sFrom managed to bare-metal — compliance line and load profile decide, not trends.
ObservabilityOTel · Grafana · LokiVendor-neutral, OSS-only — no telemetry lock-in.
By the numbers
This is hafencity.dev
15+ Experts
Engineers, designers, and strategists working as one practice from our Hamburg HQ.
50+ Clients
Companies across consumer, healthcare, and B2B trust us with their digital products. Long-term partnerships are the default.
97% Recommendation rate
Repeat engagements and references our buyers actually call. Trust compounds when delivery does.
50+ Launches
Custom mobile and web products shipped from concept to maintenance — owned end-to-end by our team.
100% In-house
Strategy, design, and engineering all live at our Hamburg HQ. One team, one project lead, accountable to you from kickoff to launch.
Since 2023
Helping companies ship digital products — and growing alongside the teams we work with.
Next steps
Let's talk about your project
Book a 30-minute discovery call. We'll review your goals, surface unknowns, and outline how we would run the engagement.