---
title: "Distributed systems — ZudoJS Academy"
description: "What changes when your system spans processes and machines: partial failure, consistency, contracts between services, retries and circuit breakers, and transactions that cross service boundaries."
source: https://zudojs.oyinlola.site/learn/distributed-systems
---

LEVEL 16 · PRODUCTION

Course Advanced

# Distributed systems

What changes when your system spans processes and machines: partial failure, consistency, contracts between services, retries and circuit breakers, and transactions that cross service boundaries.

- **4 lessons**
- **4 h** to read and try
- **Before this:** [ZudoJS architecture](https://zudojs.oyinlola.site/learn/zudo-architecture)

0 of 4 lessons done

[Start lesson 1 →](https://zudojs.oyinlola.site/learn/dist-fundamentals)

## When you finish, you can

- Reason about partial failure, time and consistency
- Version contracts between services
- Apply timeouts, retries with backoff, circuit breakers and fallbacks
- Coordinate work across services with sagas and the outbox pattern

**You build:** An order and payment flow that survives failures in each service

MODULE 1

## Distributed systems

1. [1**Distributed systems fundamentals**Simulate an unreliable network with a seeded random generator, then reason about partial failure, clocks, consistency, CAP and service discovery.55 min](https://zudojs.oyinlola.site/learn/dist-fundamentals)
2. [2**Contracts between services**Keep services that deploy on different days talking: version API, event and message schemas, evolve them safely, and catch breaks with consumer-driven contract tests.55 min](https://zudojs.oyinlola.site/learn/dist-contracts)
3. [3**Failure engineering**Break ShopFlow on purpose with a seeded fault injector, then keep it serving with timeouts, jittered retries, a circuit breaker, bulkheads, fallbacks and readiness checks.60 min](https://zudojs.oyinlola.site/learn/dist-reliability)
4. [4**Transactions across services**Keep an order, a payment, stock and a shipment consistent across four services with sagas, compensations, a transactional outbox on PostgreSQL and idempotent consumers.60 min](https://zudojs.oyinlola.site/learn/dist-transactions)

## Course checkpoint

Prove you can move on. The checkpoint picks 20 questions at random from every lesson in this course. Get 16 right to pass. Your result is saved in this browser only.