API development & integration · Udupi & Mangaluru
We link your billing, website, payment gateway, accounts, courier and WhatsApp so an order typed once reaches every system, and build your own API when an app or dealer needs one. Our Udupi studio looks after each link once it is live.
In short
API integration connects two pieces of software so they pass data to each other on their own. An online payment marks the order paid, a bill reaches the accounts, a parcel gets its tracking number, and nobody retypes anything. Whirl Designs, a studio in Udupi, coastal Karnataka, builds these connections and custom APIs for businesses across India, and tests each one before it touches real money.
Start here
Not every link between two tools needs a developer. There are three ways to connect them, and we will tell you which one fits before any work starts.
Best for: Popular tools that already know each other
Best for: Simple “when this happens, do that” steps
Best for: Orders, money and tax that must never be wrong
If a ready connector does the job, we will point you to it and help you switch it on. That is often the right answer.
Our work
Facet — Diamond & Jewellery ERP
Manufacturing ERP · Private system
Facet is the diamond and jewellery manufacturing ERP from ERP Sutra, our own product arm. It follows every lot from rough to finished piece, and keeps account of the work issued to karigars, the craftsmen, what they return, and the wastage in between.
Its GST e-invoicing runs through ClearTax. Each e-invoice carries its IRN, the reference number the government's invoice system gives it, and a signed QR code, drawn by an encoder we wrote in-house. Facet is a private system behind a login, so there is no public page to show.
Also built by us
Jayalaxmi Jewellers
Retail jewellery · Karkala
A brand site for a gold house trading since 1990, built to feel like the shop it represents — and backed by a full retail ERP handling billing, savings schemes and old-gold exchange.
Padmavathi Tours & Travels
Travel & transport · Udupi
A chauffeur-hire company with almost no online presence, rebuilt as a 190-page site that answers the exact searches its customers type — every vehicle, every route, every town.
What you get
The part people forget is what happens when something goes wrong. Each of these is written into the plan before any code is written.
How it runs
You see each connection working on your own data before it replaces anything.
We sit with the person who copies data between systems today and note every tool, every field, and every place it goes wrong.
Each provider's API documents are read and access is tested before anything is promised. Some tools open up a lot and some very little, and the written plan tells you which.
Before go-live, the person who used to do the retyping runs their own real orders through the test setup and tells us what looks wrong.
One flow, such as online payments into orders, goes live first. For a few days it runs next to the old manual way, so the two sets of numbers can be compared.
In the first weeks the failure log is checked every day and whatever shows up is fixed. Providers change their APIs and switch old versions off, so we keep each link up to date.
Not a fit
We would rather talk you out of a build than sell you one you do not need.
Questions
An API is how one system asks another for data or asks it to do something; a webhook is the other system telling yours the moment something happens. The Padmavathi Tours website, for example, calls a messaging service's API to alert the owner's phone when an enquiry arrives. A payment gateway sends a webhook when a payment succeeds, so the order is marked paid even if the customer closes the page. Most integrations use both.
A single link to a well-documented service, such as a payment gateway, an SMS service or a courier like Shiprocket, usually takes one to three weeks, testing included. Joining several systems with two-way sync, such as billing, accounts, a marketplace and an online store, usually takes six to twelve weeks. Thin documentation on the other side, and deciding which system holds the master copy of each record, stretch it the most.
In most setups, yes. Tally can take in and send out data through its own interface, so sales, receipts and stock can post into it as vouchers with nobody keying them in. We first check your Tally version and setup, because Tally must be running on a computer the connection can reach. Then we agree which entries move, and in which direction.
Yes, and it is a common request. We usually build a REST API, the standard web format most apps and partner systems already understand, with a separate key for each app or dealer. Each key sees only the data it is allowed to, every call is logged, and the API carries a version number, so an older app keeps working after a change.
Yes. Jayalaxmi Jewellers in Karkala runs this today: their ERP sends receipts and reminders on WhatsApp by itself, using approved message templates. Messages your business starts, rather than replies in a chat the customer opened, must use a template approved by Meta, so we draft and submit those with you. Our WhatsApp Business API page covers this in more depth.
It is when each link checks what it receives. An order is marked paid only when the gateway confirms it to your server, never just because the customer's browser reached a thank-you page, and the amount is matched to the order total. Each partner gets its own key, which can be switched off without touching the others, and all data travels over an encrypted connection.
Then we look for another way in: a file it can export and import on a schedule, a report it already emails, a read of its database where the maker allows it, or an add-on from its maker. These links run every few minutes or hours rather than instantly. If none of them is reliable, we will tell you so, rather than build something that stops working the day they update.
You do. Accounts with the payment, courier, messaging and tax providers are opened in your business's name, and the keys are kept on a server you control. The code and its notes are handed over as well, so another developer could take over each link without starting again.
Worth reading first
Clean, documented, tested code on a modern, proven stack — the foundation that keeps your api development & integration fast and dependable for years.
Ready when you are
Name the tools you use and where your staff type the same data twice, and you get a written plan back: what connects, how, and how each link is tested.