Introduction
Build USSD services on Just-tap shortcode 363.
Just-tap USSD Gateway
The Just-tap USSD Gateway provides USSD as a Service on shortcode 363. Build the menus and services behind them; Just-tap handles mobile-network connectivity, sends customer requests to your application, and returns your responses to the customer's phone.
At onboarding, you receive a unique routing code (also called a vendor code). Customers use it with the Just-tap shortcode:
*363*{routingCode}#For example, a vendor assigned code 10 is reached at *363*10#. This guide uses 10 only as an example. “Routing code” and “vendor code” mean the same assigned code; API field names remain as documented in the endpoint reference.
What you can build
Use USSD for payments, sales and orders, registrations, service requests, and other customer journeys that do not require an internet connection. Your application defines every menu and integrates the business systems that fulfil the service.
How it works
- A customer dials your service code.
- Just-tap sends an HTTPS request containing the session details to your application.
- Your application returns JSON with the next menu or final message.
- Just-tap delivers the message through the mobile network.
- If the response continues the session, the customer's next entry is sent in another request.
Responsibilities
| Just-tap handles | Your application handles |
|---|---|
| Receiving and normalising mobile-network USSD traffic | Defining menus and processing customer input |
| Routing requests to your registered endpoint | Verifying requests using the configured security mechanism |
| Sending documented JSON requests | Storing session state and validating each step |
| Translating your JSON responses for the mobile network | Performing business operations and preventing duplicates |
Your integration is one HTTP endpoint that receives and returns JSON. Do not return CON or END prefixes, XML, Freeflow headers, or plain text; those belong to other mobile-network interfaces and are not part of the Just-tap vendor contract.
Before you begin
For live gateway requests, your application needs a public HTTPS URL without redirects. You also need the routing code assigned during onboarding, the exact endpoint URL registered with Just-tap, confirmation of the request-authentication configuration, and the applicable UAT instructions.
To confirm before publication: Add the onboarding contact or portal, how endpoint URLs and secrets are configured, whether a sandbox or test shortcode exists, and how vendors receive their assigned code.
Next steps
- Follow Session Flow to simulate a first menu and understand the lifecycle.
- Use Vendor Application Design to build reliable journeys.
- Implement the Vendor USSD Endpoint and Signing requirements.