USSD Flow Simulator
Dial a short code and walk a USSD menu tree on a phone-screen emulator —
with a protocol trace showing the MAP operations, TCAP dialogue and the
SMPP ussd_service_op mapping underneath. Built for the operator
side, not just Africa's-Talking app devs.
Runs entirely in your browser
Why the trace matters
USSD debugging usually stops at the handset. This tool shows what happens
on the network: whether a step is a mobile-initiated pull
(processUnstructuredSS-Request), a network prompt expecting a
reply (unstructuredSS-Request) or a one-way notify, and how
each maps to the SMPP PDUs a gateway would emit.
FAQ
What does the protocol trace show?
For each step it names the MAP operation (processUnstructuredSS-Request, unstructuredSS-Request, unstructuredSS-Notify), the TCAP verb (BEGIN/CONTINUE/END) and the equivalent SMPP ussd_service_op mapping — because most USSD gateways front SMPP.
How do I define a flow?
As a small JSON tree of nodes with menu text and input→node options. Load one of the built-in examples to see the shape, or paste your own; the simulator validates it live.
Does it check the 182-character limit?
Yes. Menus over the 182-octet GSM 7-bit USSD limit are flagged, and any text needing UCS-2 is called out because many handsets truncate or garble it.
USSD gateway integration notes (PDF)
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Stuck on a real integration?
These tools come from day-job work: SMSC/STP/Sigtran, SMPP hookups, USSD gateways and WebRTC. If a paste here turned into a rabbit hole, that's exactly what we do.