Rotula is built for the way groups already save together: a contribution everyone agrees to, a schedule everyone can see, and turns taken in order. The conversation stays in the channel the group already uses. The record and the settlement move onto Stellar.

1. Agree the rules. Members, contribution amount, group type, and rotation are captured for the group.
2. Contribute. Each member pays the agreed amount into the group, in the configured Stellar token.
3. Take turns. A rotational group pays the next member in contract order from the pool; a goal-based group lets a member withdraw against their own recorded savings.
4. See it settle. Contributions, payouts, and pauses are Stellar transactions and Soroban events, not just messages in a group chat.

Rotula puts the parts of a savings circle that need to be provable onto Stellar, and leaves the rest where it belongs.

• Settlement on Stellar. Contributions and payouts are transactions on the Stellar network, so a group's money movement can be checked rather than trusted.
• Rules as Soroban contracts. A Rust contract models rotational and goal-based groups, with member authorization, contribution checks, ordered payouts, pause controls, and contract events.
• Accounts, assets, and SEP-10. Stellar accounts and trustlines carry a configured token; SEP-10 challenge transactions back member authentication.
• Honest state. A submitted transaction is pending until Stellar confirms it. Rotula reconciles on-chain contribution state against its own records instead of assuming success.

Stellar · Soroban · WhatsApp · Rust · TypeScript