Modernising a legacy system without stopping the business
Rewriting a critical system from scratch is one of the riskiest projects a business can take on. Incremental replacement is slower to describe and far safer to deliver.
Service 06
Connect your systems so data moves once, correctly
We design and build APIs and integrations that connect your CRM, finance, operations and customer-facing systems. The result is data that moves automatically, fails loudly when something goes wrong and can be traced when someone asks why.
- Outcome
- Your systems share accurate data without anyone copying it between them.
- Typical stack
- Node.js, TypeScript, Python, GraphQL, PostgreSQL, Redis, Stripe, AWS
When this is the right call.
Data is re-keyed between systems
Orders, customer details or invoices are copied by hand from one system to another, creating delays, duplicates and mistakes.
Integrations break without warning
Existing connections fail silently, so problems surface only when a customer complains or the month-end figures do not reconcile.
Partners need access to your data
Customers, suppliers or resellers want to connect to your platform, and you need a secure, documented API to offer them.
Too many point-to-point connections
Years of one-off scripts and plugins have created a tangle that nobody fully understands and everyone is nervous to change.
What you get.
Third-party system integrations
Connections to CRMs, ERPs, accounting packages, payment providers, shipping carriers and other platforms your business depends on.
Public and partner APIs
Well-designed REST or GraphQL APIs with authentication, rate limiting, versioning and clear documentation for external developers.
Webhooks and event pipelines
Event-driven integrations that react to changes as they happen, with queuing and retries so nothing is lost.
Data synchronisation
Scheduled and real-time syncs between systems, with conflict handling and reconciliation reports.
Integration monitoring
Logging, alerting and replay tools so failures are caught quickly and can be fixed without guesswork.
How we approach it.
Integration work is mostly about the edge cases. Before building, we establish which system is the source of truth for each piece of data, what should happen when records conflict, and how failures are detected and recovered. Getting those decisions agreed up front prevents most of the problems that make integrations unreliable.
We design every integration to be idempotent, so a retried message never creates a duplicate order or payment, and to queue work rather than depending on every system being available at once. Third-party APIs change and go down; we build defensively around rate limits, timeouts and version changes, and we test against sandbox environments and recorded real responses.
APIs we build for others to consume are designed contract-first, with an agreed specification before implementation, and documented so an external developer can get started without a call. Everything is logged in a way that lets your team answer the question of what happened to a given record. Credentials sit in your own secrets management, and the code and documentation are yours.
Tools we use for this work.
From first conversation to production.
- DiscoverUnderstand the business, the users and what success looks like.
- DefineRequirements, architecture, scope and a roadmap you can plan around.
- DesignThe product experience, tested before it is expensive to change.
- BuildEngineering in short cycles, with working software to review every sprint.
- LaunchTesting, deployment and making sure it holds up in production.
- EvolveSupport, improvement and scaling once real usage starts.
Common questions.
What does an integration project typically cost?
Cost depends on how many systems are involved, the quality and documentation of their APIs, the volume and complexity of data being moved, and how much transformation is required. Integrating with a well-documented modern API is far simpler than working with an older system that has limited access. We usually assess the systems involved before giving an estimate.
Can you integrate with a system that has no API?
Often, yes. Options include database-level access, file-based exchange, email parsing or, as a last resort, automating the user interface. Each carries different reliability trade-offs, which we explain before recommending one.
What happens when a connected system is down?
Well-built integrations expect it. We queue messages and retry with sensible back-off, alert your team if something stays broken, and provide a way to replay failed items once the issue is resolved, so no data is quietly lost.
Do you support integrations after they go live?
Yes. Third-party APIs are updated and deprecated regularly, so integrations need occasional attention. We offer ongoing support with monitoring and updates, or we hand over with documentation and runbooks so your team can manage them.
REST or GraphQL for our API?
REST is the right default for most public and partner APIs because it is widely understood and easy to cache. GraphQL suits cases where different clients need very different shapes of data, such as a complex product consumed by several frontends. We recommend based on who will use the API and how.
Further reading.
How to scope a software project before you ask for quotes
Vague briefs produce quotes that cannot be compared. A few days of structured thinking before you contact suppliers will save weeks of confusion later.
Custom software or off the shelf? When building is worth it — and when it isn't
Most businesses should buy far more software than they build. The skill is recognising the small number of places where building your own genuinely pays off.
Often paired with.
- Custom Software DevelopmentBespoke business systems, internal platforms and workflow tools designed around your processes and owned outright by you.
- AI Development & AutomationLLM-powered features, AI agents and document automation built on Claude and OpenAI, designed for dependable production use.
- Cloud & DevOpsCloud architecture, infrastructure as code, CI/CD pipelines, monitoring and cloud cost optimisation.
Have a product worth building?
Tell us what you are trying to achieve. The first conversation is about understanding the problem — not selling you a solution.