Pelikuni

A digital wallet system built in Rust, demonstrating microservices architecture, event-driven design, and payment domain modeling.

Architecture

pelikuni-wallet/
├── wallet-service/     # Core wallet API (Actix-web + SQLx + Postgres)
├── history-service/    # Transaction history consumer (Kafka)
└── shared/             # Domain events and shared types

Tech stack: Actix-web · SQLx · PostgreSQL · Kafka (rdkafka) · tokio · tracing

Design decisions:

• Optimistic concurrency via a version field on wallets — concurrent updates are detected and rejected cleanly rather than silently overwriting
• Event-driven — every state change (funded, transferred) emits a WalletEvent to Kafka, consumed by history-service for an immutable audit trail
• Shared types in a dedicated crate — WalletEvent is defined once and used by both producer and consumer services, preventing schema drift

API

Method	Path	Description
POST	/wallets	Create a wallet
GET	/wallets/:id	Get wallet by ID
POST	/wallets/:id/fund	Fund a wallet
POST	/wallets/:id/transfer	Transfer to another wallet
GET	/users/:user_id/wallets	List wallets for a user
GET	/health	Health check

Running locally

Prerequisites: Rust, Docker, sqlx-cli

# Install sqlx-cli
cargo install sqlx-cli --no-default-features --features postgres

# Start Postgres and run migrations
./scripts/init_db.sh

# Run the wallet service
cargo run -p wallet-service

The service listens on http://localhost:8000 by default.

Configuration is loaded from wallet-service/configuration/. Copy base.yaml and create a local.yaml for local overrides.

Example usage

# Create a wallet
curl -X POST http://localhost:8000/wallets \
  -H "Content-Type: application/json" \
  -d '{"user_id": "user-abc"}'

# Fund it
curl -X POST http://localhost:8000/wallets/{id}/fund \
  -H "Content-Type: application/json" \
  -d '{"amount": "100.00"}'

# Transfer to another wallet
curl -X POST http://localhost:8000/wallets/{from_id}/transfer \
  -H "Content-Type: application/json" \
  -d '{"to_wallet_id": "{to_id}", "amount": "25.00"}'

Roadmap

• Kafka event publishing on fund and transfer
• history-service Kafka consumer storing immutable transaction log (planned Q3 2026)
• Integration test suite
• Open Payments integration via signet-http
• Authentication middleware

License

MIT