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Senior web & app development · 20 capabilities
oakstone.digital
Apps & software / capability

API & third-party integrations
so nobody re-types data.

CRMs, ERPs, payments and internal tools connected so the data stops being re-typed by people.

This is for you if
  • Someone exports a CSV weekly to keep two systems aligned
  • Sales and finance disagree about the same customer record
  • An integration breaks silently and you find out from a client
A sharper way forward

The work should
change the numbers.

Tools we reach for
OpenAPIZodNode.jsTypeScriptSalesforceHubSpotNetSuiteXero

Integration work is where most digital projects quietly lose their time. Two systems each hold a version of the truth, the field names nearly match, and a capable person spends four hours a week reconciling the difference by hand.

We treat integrations as products rather than plumbing. That means an explicit contract, defined behaviour when the far end is down, idempotent writes, replay tooling and monitoring that tells you a sync is failing before a customer does.

Sometimes the right answer is a managed connector and thirty minutes of configuration. We will tell you when that is the case rather than billing you for a bespoke pipeline you did not need.

What's included

What the engagement
actually contains.

01

Systems and data mapping

The source of truth for each field agreed, and conflict rules decided before anything is written.

02

Contract-first development

Typed schemas and generated clients so a change upstream fails at build rather than in production.

03

Resilience patterns

Retries with backoff, idempotency keys, circuit breakers and dead-letter queues as standard.

04

Webhook infrastructure

Signature verification, replay endpoints and event logs for every inbound and outbound event.

05

Sync monitoring

Dashboards and alerts on lag, failure rate and record counts, owned by a named person.

06

API publishing

Where you are the provider: versioning, authentication, rate limiting and developer documentation.

What you get
  • Integration services deployed and monitored
  • Field mapping and conflict-resolution specification
  • OpenAPI schema and generated clients
  • Event log with replay tooling
  • Alerting rules and on-call runbook
  • Developer documentation for published APIs
Signals it is time
  • Someone exports a CSV weekly to keep two systems aligned
  • Sales and finance disagree about the same customer record
  • An integration breaks silently and you find out from a client
  • Your partners are asking for API access you cannot provide
Common mistakes we fix

What usually went wrong
before we were called.

  • 01No agreed source of truth per field, so both systems overwrite each other
  • 02Retrying without idempotency keys and creating duplicate records
  • 03Silent failures with no alerting and no replay path
  • 04Building a bespoke pipeline where a supported connector would do
How we measure it
  • Sync success rate and lag
  • Manual data entry hours removed
  • Duplicate and mismatch rate
  • Time to detect a broken integration
Typical timeline

2–6 weeks per integration, depending on the far end

Practicalities

What week one
actually looks like.

First week

Field-level mapping with an agreed source of truth per field and a written decision on behaviour when the far end is unavailable. Then a sandbox sync before anything writes to production.

What we need from you
  • API credentials for both systems
  • A data owner to settle conflicts
  • Volume and frequency expectations
  • Sandbox environments where available
Not included
  • Third-party licence or API usage fees
  • Cleaning historical data quality issues
  • Changing the far system’s own logic
  • Ongoing manual reconciliation

Scope boundaries stated up front rather than discovered in a change request.

How the work runs

Four stages, visible throughout.

01

Model

The domain, data and permissions written down before any interface exists, because the schema outlives every screen above it.

02

Prototype

Flows and states tested as a clickable prototype, so the expensive disagreements happen in Figma rather than in code.

03

Ship in slices

One workflow at a time, in production, with tests and observability included in the definition of done.

04

Operate

Release tooling, monitoring and a documented handover so your team can run and extend what we built.

Questions buyers actually ask

API & third-party integrations, answered.

Buy when the mapping is standard, the volume is modest and the vendor supports both ends. Build when the logic is yours, the volume is high, or the connector cannot express your rules without a fragile pile of filters. We audit that honestly — a build we do not need is bad business for both of us.

Defined behaviour, agreed with you in advance: queue and retry, degrade gracefully, or fail loudly. The point is that the answer is a decision rather than an accident, and that the queue drains automatically when service returns.

Yes. Typical findings are missing idempotency, unverified webhooks, no retry policy and no alerting. We stabilise first, monitor second, then improve — usually in that order, because stability is what stops the support tickets.

A better brief starts here

Make api & third-party integrations useful.

Bring us the hard thing. We will bring a point of view, a senior team and a clear next step.

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