About Stackr
Mission
Most of Africa transacts on USSD — not apps, not browsers. Stackr is the API that brings stablecoin payments to the channel people already use. Developers integrate our API, and their users get access to USDC transfers, bill payments, and cash-in/cash-out — from any phone. No smartphone required. No data plan required. Just a phone number and a 4-digit PIN.
Why Stellar?
USSD sessions timeout after ~30 seconds. That constraint eliminates most blockchains. Stellar was chosen because:
- •3-5 second finality — fast enough for USSD
- •Near-zero transaction fees ($0.00001)
- •Built-in DEX for token swaps
- •SEP-24 protocol for standardized fiat on/off ramps
- •USDC natively issued on Stellar by Circle
- •Fee bump transactions — users never need to hold XLM
Why Rust?
Financial infrastructure has zero tolerance for memory bugs, data races, or panics under load. Rust gives us memory safety without garbage collection, fearless concurrency with Tokio, and the performance to handle USSD's latency constraints. The type system catches entire categories of bugs at compile time.
Open Source
Stackr is MIT licensed. The entire codebase — wallet derivation, transaction signing, state machine, API — is open for audit, contribution, and deployment.
The goal is infrastructure that any operator can deploy to serve their market. Change two environment variables (FIAT_CURRENCY and FIAT_COUNTRY) and you have a stablecoin payment system for a new country.