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Track 04 · Intermediate

FinTech, APIs & compliance

Payments, ledgers, and API design — plus the compliance edges that quietly break systems when money meets code.

Money code is unforgiving: a rounding error is a bug, a missed regulation is a fine. This track walks through how money actually moves — double-entry ledgers, payment APIs, idempotency — and the compliance realities that shape every financial system you'll build or rely on.

What you'll be able to do

  • Reason about money movement with double-entry ledgers
  • Design payment APIs that survive retries and failures
  • Recognize the compliance edges before they bite
  • Tell a real reconciliation problem from a rounding myth

Inside the track

  1. 01

    Double-entry intro

    Every movement debits one account and credits another — the invariant that lets you reconcile.

  2. 02

    Payments & money movement

    How a transfer actually clears, and exactly where it can fail midway.

  3. 03

    Idempotency & retries

    Designing APIs so a retried payment never charges the customer twice.

  4. 04

    API design for money

    Contracts, errors, and audit trails that hold up under real scrutiny.

  5. 05

    Compliance edges

    KYC, AML, and the regulatory lines that quietly change how you build.

Start your streak on FinTech, APIs & compliance.

Take a free starter lesson on the web, then carry your streak straight into the mobile app and keep the daily reps going.

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