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Engineering

Backend Development Services for Complex, High-Traffic Systems

We build the server-side systems beneath your product, including data models, business logic, queues and the infrastructure that keeps them fast under load.

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Built by senior engineers
How we work

Once a product has real users, its real problems show up in the backend. A schema that worked for a hundred customers locks up at ten thousand. Business logic gets duplicated across three services because nobody agreed on ownership. Background jobs fail silently until a customer notices. We treat the server side as a whole instead of one layer: the data model, the logic on top of it, the queues and workers for work that should not block a response, and the caching and scaling decisions that keep it fast.

Most of this work starts with a system that already exists and already has traffic. That changes the approach: schema changes need a migration plan that doesn't lock the table for an hour, a monolith gets split into services incrementally rather than rewritten, and every performance claim gets checked against a load test rather than a guess. Observability, meaning logs, traces and metrics that actually show where time is going, goes in early so the next slowdown is a dashboard finding instead of a mystery.

Backend covers the server-side system as a whole. If the immediate need is a documented, versioned API contract for outside partners, see API development. If it's the browser layer, see frontend development.

What we deliver

Backend Development services

  • Data Modeling and Database Design

    Schema design for new systems and schema migration for growing ones, with indexes and constraints matched to how the data is actually queried, not just how it's structured on paper.

  • Business Logic and Domain Services

    Core application logic organized around clear ownership boundaries, so a rule about pricing or eligibility lives in one place instead of being copied into every service that needs it.

  • Queues and Background Workers

    Asynchronous processing for anything that shouldn't block a user's request: sending emails, generating reports, processing uploads, with retry logic and dead-letter handling for jobs that fail.

  • Caching Strategy

    Caching applied where it actually reduces load, at the database, application or CDN layer, with invalidation rules that prevent it from serving stale data past the point anyone would tolerate.

  • Performance Tuning and Query Optimization

    Identifying and fixing the specific queries, N+1 patterns and lock contention that are actually slowing the system down, verified with load testing rather than assumed from a code read.

  • Horizontal Scaling and Load Balancing

    Architecture that can add capacity by adding instances rather than a bigger single server, with load balancing and session handling designed to support it.

  • Observability

    Structured logging, distributed tracing and metrics that show where a request actually spends its time, so a slowdown is diagnosed from a dashboard instead of a guess.

  • Service Decomposition

    Breaking a monolith into services incrementally, along real ownership boundaries, with each extraction tested and rolled out independently rather than as one large rewrite.

You receive

Deliverables

  • A revised database schema with a tested migration plan
  • Service code committed to your repository
  • Queue and background worker infrastructure with retry handling
  • A caching layer with documented invalidation rules
  • Load test results comparing before and after performance
  • Observability dashboards covering latency, error rate and throughput

How we work

Our backend development process

  1. System and Load Audit

    We profile the current system under realistic load to find out what's actually slow, rather than starting from an assumption about which part needs the most work.

  2. Data Model Redesign

    Schema changes are planned with a migration path that keeps the system running, including how to handle in-flight data during the transition.

  3. Build Core Services

    Business logic is built or refactored around clear ownership boundaries, so the same rule doesn't need to be reimplemented in multiple places later.

  4. Introduce Queues and Caching

    Work that doesn't need to block a response moves to background processing, and caching is added where load testing shows it will actually help.

  5. Load Testing

    The updated system is tested against realistic and peak traffic patterns before launch, not just functional correctness under light load.

  6. Observability and Handover

    Dashboards and alerts go live alongside the new system, and your team gets documentation on how to read them and what to do when something trips.

Where Caching Helps and Where It Hides Bugs

Caching fixes a specific problem: the same expensive computation or query happening repeatedly for the same result. Applied there, it's close to free performance. Applied broadly, as a default reflex for anything slow, it starts hiding real problems, such as a query that should have an index but instead gets papered over with a cache layer nobody remembers to invalidate correctly.

We apply caching after profiling shows where the repeated work actually is, with an explicit invalidation rule for each cache, so stale data has a defined maximum lifetime instead of an open-ended one.

Breaking Apart a Monolith Without a Rewrite

A full rewrite carries real risk: the existing system, however messy, encodes years of edge cases a rewrite will quietly drop. We extract services incrementally instead, starting with the domain that has the clearest boundary and the most independent traffic pattern, testing each extraction against the existing behavior before moving to the next.

This takes longer to reach a fully decomposed architecture than a rewrite would in theory, but it keeps the system shipping features the entire time, and each extracted service is validated against real production behavior rather than a specification written from memory.

Queues for Work That Shouldn't Block a Response

Sending a confirmation email, generating a report or resizing an uploaded image doesn't need to happen before the user gets a response. Moving that work to a background queue makes the request faster and gives you a natural place to add retry logic for the parts that occasionally fail.

The part teams usually get wrong is what happens when a job fails repeatedly: without a dead-letter queue and an alert, a failing job just disappears, and the customer complaint is how you find out.

  • Asynchronous processing for anything that doesn't need to block the response
  • Retry logic with backoff for transient failures
  • Dead-letter handling and alerting for jobs that fail repeatedly

Budget

What drives cost and timeline

  • Current traffic and expected growth

    A system built for its current load needs different decisions than one built to handle ten times that traffic within a year.

  • Number of services or domains involved

    A single well-scoped service is a smaller project than untangling business logic spread across several services with unclear ownership.

  • Data migration complexity

    Schema changes on a table with a few thousand rows are a different project than the same change on one with hundreds of millions and live traffic.

  • Real-time feature requirements

    Websockets, streaming updates and live dashboards add infrastructure and testing surface beyond a standard request-response backend.

  • Compliance and audit logging needs

    Systems that must retain a verifiable audit trail of every change need that logging designed in from the start, not added after the fact.

Compliance

Standards we design and build to

None of these is a certification or attestation held by this agency. They are the standards we design and build client systems to, so your own audit or assessment starts from a sound base.

  • GDPR / UK GDPR

    Personal data handled on a lawful basis, with data minimisation and a documented retention policy.

  • HIPAA safeguards

    Administrative, physical and technical safeguards applied where a system touches protected health information.

  • PCI DSS scope reduction

    Card payment flows tokenised through a certified processor so cardholder data never touches your systems.

  • SOC 2 readiness

    Access control, change management and audit logging built in from day one, ready for a client's own SOC 2 audit.

  • WCAG 2.2 AA

    Keyboard navigation, colour contrast and screen-reader labelling checked against the AA success criteria.

  • OWASP ASVS

    Authentication, session handling and input validation reviewed against the Application Security Verification Standard.

We list certifications only when they are real and current. See our security practices →

FAQ

Questions about Backend Development

How do you redesign a database schema without downtime?

We add new columns or tables alongside the old ones, backfill data in batches, and switch reads over once the new structure is verified, rather than locking the table for a single large migration. The exact steps depend on your database engine and current traffic, but the goal throughout is that the application keeps serving requests the whole time.

Can you fix a slow checkout flow without rewriting the whole backend?

Usually yes. Checkout slowdowns are often traceable to a specific query, lock contention or an uncached lookup rather than a fundamental architecture problem. We profile the flow under realistic load first to find the actual bottleneck before recommending anything as large as a rewrite.

What's the difference between caching at the database layer and the application layer?

Database-layer caching (like a query cache) speeds up repeated identical queries automatically but offers little control over invalidation. Application-layer caching (like an in-memory or Redis cache) lets you cache computed results with explicit invalidation rules, at the cost of needing to manage that logic yourself.

How do you decide when to split a monolith into services?

We look for a domain with a clear boundary and an independent scaling or deployment need, such as a reporting module that's slowing down the main application under load. Splitting happens incrementally from there, one service at a time, rather than as a single large rewrite.

Can you add background job processing to an app that currently does everything synchronously?

Yes. We identify which operations don't need to block the user's response, such as sending emails or generating reports, and move those to a queue with retry and failure handling. The parts of the app that genuinely need an immediate response stay synchronous.

How do you find out what's actually causing our production slowdowns?

We add structured logging, tracing and metrics if they aren't already in place, then profile the system under realistic traffic to see where requests actually spend their time. That replaces guesswork with a dashboard that points at the specific query, lock or service causing the delay.

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