Your developer's quote has a line that says "REST API integration with Razorpay" or "GraphQL backend". You are paying for it, but you are not sure what it means or whether the choice matters for your business.
It does matter, but not in the way most tech articles say. This guide explains what an API is, using connections you already use, like your payment gateway, WhatsApp and Shopify. Then it covers REST vs GraphQL in plain words, and the questions to ask before work starts.
Quick answer
What is an API, in plain words?
An API (application programming interface) is a set of rules that lets one program talk to another. MDN, the web reference run by Mozilla, calls it "a set of features and rules" that lets software interact with a program, "as opposed to a human user interface". You use a screen; your software uses an API.
The waiter example
Think of a restaurant. You do not walk into the kitchen to cook your own food. You give your order to a waiter in a set way, and the waiter brings back what you asked for.
An API is that waiter. Your billing app gives an order ("take ₹500 from this customer") in a fixed format, and the payment company's system sends back an answer ("paid" or "failed").
APIs your business already depends on
You probably use several APIs today without seeing them. Each row below is taken from that company's own developer pages.
| Connection | What the API lets your software do | How it works, per official docs |
| Razorpay payment gateway | Take payments, including from UPI apps | REST, answers sent as JSON |
| WhatsApp Business Platform | Send messages from your own software | HTTP requests, built on Meta's Graph API |
| Shopify | Manage products and orders from an app | GraphQL Admin API; the REST Admin API is legacy |
| TallyPrime | Sync accounts with other systems | JSON, XML or ODBC connections |
JSON here means a plain text format for sending data, with labels and values, like "amount: 500". Most modern APIs send their answers in it.
What API development means for you
API development is building your own API, so your website, your mobile app and maybe your partners can all read the same data. If you only have a website, you may not need a separate public API at all. If you plan an app later, ask for one from the start so the app does not need a second backend.
REST vs GraphQL: what is the difference?
Both are ways to design an API. REST gives each kind of data its own address (URL), like separate counters for orders and for customers. GraphQL has one address, usually ending in /graphql, and the app writes a request listing exactly the fields it wants back.
REST in plain words
REST stands for Representational State Transfer. MDN describes it as a set of design rules where a resource, such as a document or an order, is passed between client and server in standard ways. Your app asks one address for orders and another for customers.
GraphQL in plain words
GraphQL's own site calls it "an open-source query language for APIs and a server-side runtime". The app sends one request that says, for example, "give me this customer's name, phone and last three orders". The server sends back only those fields.
| Point | REST | GraphQL |
| Addresses | Many, one per kind of data | One, usually /graphql |
| What comes back | Whatever the server set for that address | Only the fields the app asked for |
| Caching (keeping copies to save time) | Standard web caching works by URL | No URL per item, so the app builds its own cache |
| Changes over time | Often a new version, like v1 and v2 | Designed to grow without versions |
| Real example | Razorpay | Shopify Admin API |
Too much or too little data
A REST address may send more fields than one screen needs. Or a single screen may need three or four calls to different addresses. GraphQL's site says it lets you "request exactly what you need in one call", which helps on slow mobile networks.
The trade-off is caching. GraphQL's own docs note that "there's no URL-like primitive" to use as a cache key, so the developer has to plan caching with IDs instead.
Billing, stock or booking software often has to talk to Razorpay or WhatsApp. It helps to work with a team that has built these connections before, such as The Beyond Horizon's custom software development for Indian businesses.
REST vs GraphQL: which should your project use?
For most business apps, the choice follows the outside services you connect to and what your developers know well. If your payment gateway speaks REST, that part of your app uses REST anyway. GraphQL helps most when a website and phone apps each need different slices of the same data.
GraphQL's own FAQ says it is "not a definitive replacement" for REST, and that the two "can actually co-exist in your stack". So you rarely have to pick only one.
| Your situation | What usually fits |
| A website with an enquiry form and payments | REST, matching the payment gateway |
| A website plus Android and iPhone apps on the same data | GraphQL is worth asking about |
| A custom shop front on top of Shopify | GraphQL, since Shopify's Admin API is GraphQL |
| Sharing data with a partner company | REST is often simpler for them to use |
One project, both styles
Our own projects show this mix. The YUMI store is a custom website that reads from Shopify through its GraphQL APIs, and it checks pincode delivery through the Shiprocket API.
On HRDYAM, one payment-completion flow connects six outside services: Cashfree, Firebase, Sanity, Zoho, Resend and Google Calendar. Its login check calls a Google REST API directly.
What should you ask your developer about APIs?
Ask who owns each API account, where the secret keys are kept, and what happens when an outside service is down. Also ask whether your own API is written down, and whether outside APIs have limits or fees. The answers matter more than REST or GraphQL.
- Who owns the accounts? Your Razorpay, WhatsApp Business and Shopify accounts should be in your business name and login, not the developer's.
- Where are the API keys kept? A key is like a password for an API.
- What happens when an outside service is down? The app should show a clear message, not a blank page.
- Is our own API documented? There should be a written list of every address or query, so another developer can take over.
- Do outside APIs have limits or fees? Razorpay's docs, for example, have a section on rate limits (how many calls are allowed in a time window).
A warning: secret API keys must never sit inside website code that a browser can read. Anyone who opens the page source could copy them.
In the Vishnu Jewellers system we built, all calls go through the server, so credentials never reach the browser.
On HRDYAM, every outside service was given a defined way to fail. If one service has a problem, only that part of the page degrades instead of the whole page crashing.
A small tip: when the project ends, ask for a list of every API key, which account it belongs to, and how to change it. If you part ways with a developer, change those keys the same week.
Before you sign off on the API plan
REST vs GraphQL is a design choice your developer should explain in two sentences, tied to your project. If they cannot, ask again.
Want a second opinion on an API plan, or need your software connected to Razorpay, WhatsApp or Shopify? Call or WhatsApp The Beyond Horizon on +91 75973 92744. We have built 40+ projects, and we can tell you which connections your plan really needs.