Backend and API development in Python and Node.js
Backend development rarely fails dramatically. Systems get slowly harder to change, until a one-line feature takes a week and nobody can say with confidence what a deploy will break. That is a data-model and boundaries problem, not a hardware one.
Concretely, what ships
A data model that matches your domain
Schema designed around what your business actually does, with constraints in the database rather than hoped for in application code. Migrations are versioned and reversible.
Typed, documented APIs
REST or GraphQL with a generated OpenAPI or schema document, consistent errors, pagination, and versioning that lets you change things without breaking existing clients.
Authentication and authorisation done properly
Sessions or tokens with sensible expiry and rotation, role and tenant boundaries enforced server-side, secrets in a secret manager, and an audit trail for anything that touches money or personal data.
Background jobs and pipelines
Queues for anything slow or failure-prone, with retries, dead-letter handling and idempotent handlers — so a duplicate webhook does not charge a customer twice.
Integrations that fail safely
Third-party APIs treated as unreliable by default: timeouts, retries with backoff, circuit breaking, and a defined behaviour when the provider is down rather than a stack trace shown to the user.
Observability from day one
Structured logs, metrics and traces, with alerts on the things that actually indicate a problem. Load-tested against your expected traffic before launch, not after.
- 01
Domain and data modelling
We map entities, relationships and access rules first. This is the cheapest hour of the project and the most expensive one to skip.
- 02
API contract before implementation
The schema is agreed and published so frontend and mobile work can start in parallel against a stub instead of waiting.
- 03
Build with tests where they earn their keep
Heavy coverage on business rules and data integrity, lighter on glue code. Tests as a safety net for changing things later, not as a coverage number.
- 04
Deploy, observe, hand over
Infrastructure as code, CI/CD, runbooks and dashboards, in your cloud account.
- Your backend has become slow to change and risky to deploy
- You need an API for a mobile app or third-party partners
- You have data arriving faster than your current reporting can handle
- You need integrations that do not silently corrupt data when a provider fails
- Python
- FastAPI
- Node.js
- PostgreSQL
- Redis
- Celery / queues
- OpenAPI
- Docker
Helios — Energy Analytics Platform
Real-time dashboard processing millions of meter readings, with forecasting and anomaly alerts for grid operators.
Backend & APIs — common questions
If yours isn't here, ask us directly — we answer within one business day.
Python or Node.js — how do you choose?
Python when the work leans on data, machine learning or scientific libraries, or when your team already writes Python. Node.js when the backend is mostly IO-bound API work and sharing TypeScript types with a React or React Native frontend removes a whole class of bugs. Both are boring, well-supported choices. We will pick the one your team can maintain, not the one that is fashionable.
Can you fix our existing backend instead of rewriting it?
Usually, and it is normally the better answer. We start with a read-only review and give you a prioritised list of what is actually causing the pain — often a handful of missing indexes, an N+1 query, and one badly-placed synchronous call rather than the architecture. Where a rewrite genuinely is warranted, we do it incrementally behind the existing API so you are never mid-migration with nothing working.
How do you handle security and compliance?
Standard practice as a baseline: least-privilege access, secrets in a manager rather than environment files in git, encryption in transit and at rest, dependency scanning in CI, and audit logging on sensitive operations. If you are subject to a specific regime — GDPR, HIPAA, SOC 2 — tell us during scoping so the requirements shape the design instead of being retrofitted.
AI automation and custom chatbot development
Tell us what you're building
We'll come back within one business day with a clear plan and an honest estimate.