We built a Splitwise alternative where the link is the account

Описание и применение

Создано приложение для разделения расходов без регистрации: ссылка служит как приглашение, вход и ключ доступа, обеспечивая простоту, офлайн‑работу и безопасность.

Задача

Users would not create accounts, so the product needed to be accessed via a single link that served as invite, login, and data key.

Результат

A fully functional split‑expense app that requires no account creation, supports offline usage, and maintains privacy and security through a single link bearer credential.

Рабочий процесс

• Generate a 16‑byte random key, base64url‑encode it, and append to a readable URL stem.
• Use the link as a bearer credential; no recovery or owner override. Use BigInt for money amounts; display as strings. Lock FX rates at entry; never re‑price history. Queue new expenses offline and replay when online. Use SSE to notify clients of changes; clients refetch data. Route all external requests through an allow‑listed proxy to avoid egress from containers.

Доказательства

The link is a bearer credential. 16 random bytes, base64url, appended to a readable stem. No recovery, no owner override. Treat it like a key.

Источник

Money as strings + BigInt. A Number never touches an amount except for display.

Источник