DEVELOPER GUIDE

Before You Begin

What you need before integrating Zepto Flow: API keys, environments, and the SDK.

Before you integrate Flow, make sure you have the pieces below in place.

Your API key

You create Payment Intents server-to-server with your secret API key. Keep the key on your backend.

Never expose your secret API key in the browser

Your secret key can create and manage payments. Only the token from create-payment-intent reaches the browser. That token works for a single Payment Intent only.

Environments

Flow runs in two environments:

Environment	Use it for
Sandbox	Development and tests. Flow simulates the payments. No real money moves.
Live	Production traffic.

A token from one environment works only with the SDK bundle for that same environment. Do your development against the sandbox. Then switch both your backend endpoint and your bundle URL when you go live. See Test in the sandbox.

The Flow SDK

The widget ships as a single self-contained browser bundle, one per environment. Load the bundle for your environment with one <script> tag:

<!-- Sandbox -->
<script src="https://go.sandbox.zeptopayments.com/flow/assets/flow.js"></script>

<!-- Live -->
<script src="https://go.zeptopayments.com/flow/assets/flow.js"></script>

The bundle exposes a ZeptoFlow global. It bundles its own runtime, so you install nothing. It renders into a shadow root. Its styles never collide with your page.

One bundle per environment

Load the bundle for the environment your token was created in. A sandbox token does not work with the live bundle.

Next steps

After you have your key and know your environment, create your first Payment Intent.