Direct Integration

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Overview

Welcome to FLIZ! This guide will help you integrate FLIZ into your app to securely accept and process payments. FLIZ handles everything within an easy-to-use in-app webview, creating a seamless payment experience for your users.

Here's a video of how our webview looks within the app of one of our clients:

Step 1: Get Your API Key

1. Sign up on the FLIZ app.
2. Go to Installations → App SDK.
3. Generate and copy your API Key.

⚠️ Important: Securely store your API Key for authentication purposes.

Step 2: Set up your webhook

Add your callback URL in FLIZ app under the webhook section, and copy and save the one-time Webhook Secret. If you want to learn more about how we use webhooks go to our Webhooks guide.

Step 3: Authenticate Your App

Authenticate your app to receive a JWT token necessary for secure transactions. Please review our Authentication guide to learn more about how to authenticate with Fliz.

Step 4: Add a Transaction

Create a transaction by making a POST request to the FLIZ API, you will use the jwt from the authentication step in the header. The response will be a redirect-url with all the transaction information which you can then open in a webview.

Request

POST https://api.flizpay.de/transactions

Request Body Parameters

Parameter	Type	Description	Required
amount	Int	The transaction amount	✅
currency	String	The currency code (use 'EUR')	✅
source	String	Integration source identifier (use 'sdk_integration')	✅
metadata	Object	Custom key-value pairs (e.g. user IDs) to enrich or track a transaction	❌

Required Header

Authentication: Bearer YOUR_JWT_HERE

Example Request

curl --request POST \
     --url https://api.flizpay.de/transactions \
     --header 'Authentication: Bearer YOUR_JWT_HERE' \
     --header 'Content-Type: application/json' \
     --data '{
       "Amount": 1000, 
       "Currency": "EUR", 
       "source": "sdk_integration", 
       "metadata": { "internalCustomerId": "customer_10456" }
     }'

Example Response

{
  "redirectUrl": "https://secure.flizpay.de?token=stpdlkzgxtpyfuzm"
}

Step 5: Open the url in a Webview

After receiving the redirectUrl from Step 4, append the following query parameters:

• jwt: Your JWT token from the authentication step
• redirect-url: Your app's custom URL scheme

Final URL Example:

https://secure.flizpay.de?token=stpdlkzgxtpyfuzm&jwt=YOUR_JWT_HERE&redirect-url=myapp://

Open this final URL in a webview inside your app and Fliz will handle the rest.