Custom API Development

Make your systems talk to each other

Custom APIs and integrations that connect your website, app, billing, payments and internal tools — so data moves automatically instead of someone retyping it every evening.

What we build

Integrations and APIs for growing businesses

Custom REST APIs

Endpoints built for your business logic, with authentication, versioning and proper error handling.

Payment gateway integration

Razorpay, UPI, payment links, subscriptions and webhooks that reconcile correctly with your records.

WhatsApp Business API

Order confirmations, reminders and alerts sent automatically from your own system.

Tally & accounting sync

Move orders and invoices from your website into Tally without manual entry.

Marketplace connections

Amazon, Flipkart, Meesho, Shopify and WooCommerce — keep stock and orders in step across channels.

Mobile app backends

The API layer your Android or iOS app talks to, including authentication and push triggers.

Webhooks & automation

Event-driven flows so one action in a system triggers the right response in another.

Legacy system bridges

Older software with no modern API? We build a layer around it rather than replacing what works.

Data sync & migration

One-time migrations or scheduled syncs between databases, spreadsheets and platforms.

What you receive

Built to be handed over, not held hostage

  • Written documentation. Every endpoint described, with example requests and responses, so any developer can pick it up later.
  • A Postman collection you can use to test each endpoint yourself.
  • Staging and production environments, so changes are tested before they touch live data.
  • Your own keys and credentials. Accounts are created in your name, and access is yours.
  • Source code ownership on final payment. Nothing depends on us continuing to be involved.
  • Error handling and logging, so when something fails you find out — rather than discovering it weeks later in a reconciliation.

Pricing

Custom Quote

API work is priced by the number of systems involved and how cooperative each one is. Tell us what you want connected and what you're doing manually today, and we'll scope it properly before quoting.

Worth being clear about

  • We can only integrate what the other system allows. If a platform has no API and no export, we'll tell you at the scoping stage rather than after you've paid.
  • Third-party platforms change their APIs. Integrations need occasional maintenance — that's covered under a care plan or quoted as needed.
  • Platform fees, API subscriptions and message charges are billed by those providers directly, not by us.

How we work

Scoped before it's built

Map the flow

What data exists where, and what should happen automatically instead of manually.

Check feasibility

We confirm each system can actually do what's needed, before any commitment.

Design endpoints

Structure, authentication and failure behaviour agreed with you in writing.

Build & test

Developed against staging, tested with real cases including the ones that go wrong.

Document & hand over

Go live, with documentation, credentials and a walkthrough for your team.

Questions

Before you get in touch

The software we use has no API. Is it hopeless?

Not always. Some systems support scheduled exports, database access or file drops that we can build around. We check first and tell you honestly if it isn't workable.

Who owns the code?

You do, on final payment, along with the documentation. We reuse our own general-purpose libraries across projects, but what's built for you is yours.

What happens if a platform changes its API?

Integrations occasionally break when a provider updates. If you're on a care plan we handle it as part of the plan; otherwise we quote the fix.

Is our data safe?

Credentials are stored securely and never in code repositories, connections use HTTPS, and access is limited to what each integration actually needs. We can also work under an NDA.

Can you work with our existing developer?

Yes. We're often brought in specifically for an integration alongside an in-house team, and the documentation is written for exactly that situation.

How long does an integration take?

A single straightforward integration is usually one to two weeks. Multi-system projects depend on how quickly access and credentials come through.

Custom API development for businesses in Tamil Nadu

Most growing businesses end up running several systems that don't know about each other — a website taking orders, a billing package, a spreadsheet for stock, and a WhatsApp number where customers actually ask questions. Somebody spends an hour a day copying between them, and mistakes creep in at exactly the points that cost money.

Custom API work removes that copying. Once systems can pass data directly, an order placed online can raise an invoice, update stock, and send a WhatsApp confirmation without anyone touching it.

ZenoraTech builds integrations and custom APIs for small and medium businesses in Tiruchirappalli and across Tamil Nadu, and remotely for clients elsewhere in India. Related services: web application development, business automation, payment gateway setup and Tally & GST automation.

Tell us what you're doing manually

Describe the task someone repeats every day. That's usually where an integration pays for itself first.

Message us on WhatsApp