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Software Engineering

API Development & Integration Reliable Where It Usually Breaks

API development covers both the interfaces your product exposes and the ones it depends on. We design REST and GraphQL APIs with versioning, authentication, rate limiting, and documentation from the first endpoint, and build the integration layer connecting you to payment, CRM, ERP, and AI providers.

  • Documentation generated from source
  • Idempotent writes and replay
  • Alerting on a stalled queue
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How it runs · 5 steps

  1. Design the contract first
  2. Generate the documentation
  3. Make writes idempotent
  4. Queue the slow work
  5. Alert on the queue, not the customer

Built with

  • REST
  • GraphQL
  • OpenAPI
  • JSON Schema
  • Node.js
  • FastAPI
  • TypeScript
  • Python

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Integrations fail in production for unglamorous reasons

A partner changes a field. A webhook is delivered twice. A rate limit is hit during a batch job at 3am. We build for those from the start with idempotency keys, dead-letter queues, and replay — so a failed sync is a recoverable event rather than a support ticket about missing data three weeks later.

On the APIs you expose, the discipline is versioning and documentation from the first endpoint. A contract that changes without a version is a breaking change for someone, and documentation written by hand is documentation that is already wrong.

The Problem

What this usually fixes

  • Silent data loss

    A sync failed, nothing alerted, and the gap is discovered weeks later when the numbers do not reconcile.

  • Duplicate writes

    A webhook delivered twice created two orders, because nothing made the write idempotent.

  • Documentation that drifts

    Hand-written API docs describe last quarter's contract, so every integrator's first day is spent discovering the difference.

  • One noisy client degrading everyone

    No per-client rate limiting, so a single integrator's batch job becomes everybody's outage.

How We Work

The process

Each step produces something you can review — a document, an environment, or working software — rather than a percentage in a status report.

  1. Design the contract first

    Resources, error semantics, and versioning agreed before implementation, because the contract is the expensive part to change.

  2. Generate the documentation

    OpenAPI or GraphQL schema generated from the source, so docs cannot drift from behaviour.

  3. Make writes idempotent

    Idempotency keys on every mutating endpoint, so a retried or duplicated request is safe by construction.

  4. Queue the slow work

    Background processing with retries, backoff, dead-letter queues, and replay for anything that touches a third party.

  5. Alert on the queue, not the customer

    Monitoring that fires on a stalled queue or rising error rate rather than on an email asking where the data went.

What You Get

Why teams choose this

  • Failures that recover themselves

    Retries, backoff, and replay mean a transient third-party outage resolves without anyone opening a ticket.

  • Safe to retry

    Idempotent writes make duplicate deliveries harmless, which removes an entire category of data-integrity bug.

  • Documentation that is always true

    Generated from the source contract, so an integrator's first day is spent integrating rather than reverse-engineering.

  • Fair capacity

    Per-client rate limits keep one integrator's batch job from becoming everyone else's incident.

Stack

Technologies we build with

Tools we have delivered production work on, not a capability matrix. We pick per project and will explain the trade-off behind each choice.

Contracts
  • REST
  • GraphQL
  • OpenAPI
  • JSON Schema
Runtime
  • Node.js
  • FastAPI
  • TypeScript
  • Python
Reliability
  • BullMQ
  • Redis
  • Dead-letter queues
  • Idempotency keys
Integrations
  • Stripe
  • Razorpay
  • CRM & ERP
  • Webhooks
Industries

Who this is for

Integration work concentrates wherever money, inventory, or customer records move between systems.

  • Fintech
  • E-commerce & retail
  • Logistics
  • Insurance
  • Healthcare
  • B2B software
  • Marketplaces
  • Manufacturing
Questions

API Development: common questions

Related reading

REST or GraphQL for our API?

REST is the better default for public APIs and service-to-service communication: it is cacheable, universally understood, and simple to secure and rate-limit per endpoint. GraphQL earns its complexity when many different clients need different shapes of the same data, which is common for products with web, mobile, and partner surfaces over one domain model. The cost is real — query complexity limits, caching, and authorisation per field all need deliberate work.

How do you handle a third-party API that goes down?

Anything touching a third party runs as queued background work with retries and exponential backoff, so a transient outage resolves without human involvement. Requests that exhaust their retries land in a dead-letter queue that can be inspected and replayed once the provider recovers, rather than being silently dropped. Alerting fires on queue depth and error rate, which means you learn about a provider outage from a monitor rather than from a customer.

Can you integrate with our existing ERP or CRM?

Yes — CRMs, ERPs, payment gateways, logistics providers, and messaging platforms are routine work. Older enterprise systems often have awkward interfaces: batch files, SOAP, or a database view rather than a modern API. We build an anti-corruption layer between that system and yours so its constraints do not leak into your domain model, which keeps the integration replaceable if the underlying system is ever upgraded or swapped.

How do you version an API without breaking existing clients?

Additive changes — new optional fields and new endpoints — ship without a version bump, because they cannot break a well-behaved client. Anything that removes or changes the meaning of an existing field goes into a new version, with the previous version supported for an announced deprecation window. The important discipline is deciding this before the first external client integrates, since retrofitting versioning onto a live API is considerably harder than starting with it.
Sectors

Where we apply this

The same work looks different depending on the constraints it has to hold. These cover what changes.

Related

Services that pair with this

Which integration keeps breaking?

Most teams have one that needs manual reconciliation every month. That is usually the cheapest thing to fix first.

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