Almost every operational problem we are asked to fix turns out to be an integration problem wearing a disguise. The data exists. It is just in four systems that have never been introduced, and a person in the middle is doing the joining by hand.
API development and integration work connects separate systems so data moves between them automatically. It covers building your own REST or GraphQL APIs, consuming third-party ones, handling webhooks reliably, and the middleware that translates between systems that disagree about what a customer is.
The goal of every integration we build: data entered once, in one system, and mirrored everywhere else automatically.
Every integration we ship retries with backoff and then tells a human. Silent failures are how integrations lose trust.
Every call in and out is recorded, so 'the sync did not run' becomes a five-minute investigation rather than a day.
Failed events can be replayed for at least a day, so an outage at the other end is not permanent data loss.
Integration map with ownership
API and event specification
Working integration in staging
Reconciliation report
Live integration and a runbook
The ads platform has the lead. The CRM has the pipeline. The accounting system has the invoice. The store has the order. And someone spends their mornings copying between them, which means the numbers are stale, inconsistent, and wrong in a way nobody can prove.
Integration is invisible when it works, which is why it gets deprioritised. Here is what it is actually worth, by context.
Orders in the store, stock in a spreadsheet, dispatch in the courier's dashboard, and three of them disagree.
Order, inventory and fulfilment synced both ways, with exceptions raised rather than silently absorbed.
Leads from six sources landing in six inboxes, none of them tagged, all of them called late.
One intake pipeline: every source normalised, deduplicated, scored and routed into the CRM within seconds.
Tally or an ERP as the system of record and no way for anything else to read it, so every report is manual.
A middleware layer exposing the ERP safely to the systems that need it, without touching the ERP itself.
Appointments, records and billing in separate tools, joined by staff at the counter.
Integrated scheduling and records with a strict audit trail on every data movement.
Time tracking, project management and invoicing in three tools, so margin per project is discovered annually.
One flow from logged time to raised invoice, with profitability visible weekly.
Enterprise prospects asking for an API and an SSO integration that does not exist, and deals stalling on it.
A documented public API, webhooks for customers, and the integrations your sales team keeps losing deals over.
Most integrations are written once, work for a quarter, and then fail in a way nobody notices. Four practices prevent almost all of that.
The same event delivered twice must not create two orders. Every handler keys on an event id and does nothing the second time. This is the single most common omission in integrations we inherit.
Third-party systems go down. An integration that gives up after one failure loses data; one that retries forever hides a problem. Retry, back off, and then tell a human.
Requests, responses and failures recorded with a correlation id, so an investigation is a search rather than a reconstruction.
Your API needs versions so a client on an old version keeps working, and the integrations you consume need a contract test so their breaking change is caught by CI rather than by your accounts team.
Every system, what it owns, what it needs, and where the truth lives for each entity. Most integration projects should start by deciding which system owns the customer record.
Resources, versioning, authentication, pagination, rate limits and error shapes, agreed before implementation.
REST or GraphQL endpoints in TypeScript, with validation at the boundary and types generated from the schema.
CRM, ERP, Tally, payment gateways, WhatsApp Business API, courier and ad platform APIs — with credentials handled properly.
Signature verification, idempotency keys, a queue, retries with backoff and a dead-letter store you can replay from.
Scheduled reconciliation that compares both systems and reports differences, because event-driven sync alone always drifts eventually.
Failure alerts to the channel your team actually reads, with enough context to act rather than just to worry.
API reference, an integration runbook, and a page describing what to do when each integration fails — written for whoever is on duty, not for us.
Every tool on this list is one we have shipped and still maintain for a paying client. Nothing here is aspirational — if it is not in production somewhere, it is not on the page.
Boring, typed and observable, because integrations are debugged far more often than they are written.
Types generated from the schema, so a breaking change at the boundary is a compile error rather than a support ticket.
Handlers, workers and scheduled jobs, with the queue doing the heavy lifting rather than the request thread.
Where several clients need different shapes of the same data. REST otherwise — it is simpler to cache and simpler to debug.
Signed, idempotent, queued and replayable. The four properties that separate a reliable webhook from a data-loss incident.
The buffer between an incoming event and the slow third-party system that has to hear about it.
The list is India-shaped, because these are the systems Indian businesses actually run.
Lead creation, stage updates and closed-revenue exports back to the ad platforms.
Checkout, subscriptions, refunds and reconciliation against your own ledger rather than the dashboard.
Template messages, session handling and delivery receipts, with opt-in recorded properly.
Where a client's team genuinely works in sheets, we write into them rather than pretending they will stop.
Offline conversion imports, spend pulls and automated rule enforcement across Meta and Google.
Almost every operational problem we are asked to fix turns out to be an integration problem wearing a disguise. The data exists. It is in four systems that have never been introduced, and a person in the middle is doing the joining by hand.
Building your own REST or GraphQL APIs, consuming third-party ones, handling webhooks reliably, and the middleware that translates between systems which disagree about what a customer is. The last one is most of the work and none of the glamour.
Leads from ads and forms into a CRM with attribution attached and outcomes flowing back — the loop that decides whether your advertising improves, described in CRM integration services. WhatsApp Business API for the channel Indian customers actually read, with its session windows and template rules, covered in WhatsApp Business API integration. And Tally or an older ERP, which usually means a middleware layer rather than touching the ERP itself.
Most integration projects should begin by deciding where the truth lives for each entity — the customer, the order, the invoice. Skip that and you build bidirectional sync between two systems that both believe they are authoritative, which produces conflicts nobody can adjudicate. It is a governance decision that happens to have a technical implementation.
If enterprise deals keep stalling on integration, a documented public API with versioning, keys, rate limits and customer-facing webhooks is usually the unblocker. It is also a product surface in its own right, which means it needs a sandbox and reference documentation rather than a page of examples.
Every stage ends in something you can hold — a document, a build, a live account. If a stage cannot name its output, it is a meeting, not a stage.
What exists, what owns which record, and where the manual joins are happening today.
Endpoints, events, identifiers and error handling, agreed on paper before anything is written.
Implemented against test credentials, with a replayable event log from the first day.
Run both systems in parallel and compare, record by record, until the differences are explainable.
Alerts, dashboards, a runbook, and a walkthrough for whoever will be on duty when it fails at 11pm.
Everything here is part of the engagement at no extra cost. We do not itemise them on an invoice and we do not withhold them if you leave.
What exists, what owns which record, and where a person is doing the joining by hand. Written up and yours, whether or not we build anything.
Retries with backoff, a dead-letter store you can replay from, and an alert to a channel your team reads. Not an optional extra on our builds.
Written for whoever is on duty at 11pm, not for us — what failed, what to check, what to do.
A scheduled comparison of both systems that reports differences, because event-driven sync always drifts eventually.
So a third-party breaking change is caught by the pipeline rather than by your accounts team three weeks later.
Longer answers to the questions people ask before they hire anyone for api development & integrations.
Built by us, free, no signup, nothing uploaded to a server. Take them whether or not you ever become a client.
A single integration between two systems, built properly with retries, alerting and reconciliation, is a fixed-price project. A middleware layer connecting several systems, or a public API for your own customers, is scoped from the integration map. We produce that map first, and you keep it either way.
Tell us what you have now and what you are trying to reach. We will audit it and tell you what we would do, what it would cost and whether you need us at all. The audit is free and yours to keep.