Backend Developer · path guide

Backend Developer: path guide

Read this before you start. It explains what the role is, what you'll be able to do at the end, which core lessons you need, how to set up your tools, what it may cost and how long it really takes.

The role

A backend developer builds the part of an app that runs on servers: the APIs that apps call, the database that keeps the records, and the services that pass work between each other. The job is more than making a route return data. It is making sure each caller sees only what they may see, that a repeated tap makes one order and not two, that a busy page stays fast at lunchtime, and that nothing is lost when a server restarts or a service goes down.

Everyday applications

• A food delivery API where customers see only their own orders and a weak network can't cause a double charge.
• A menu or product page that answers in milliseconds for thousands of people, and still shows the right price a second after a change.
• Sign-in with a phone app through OAuth 2 and OpenID Connect, without the app ever seeing a password.
• An order that reaches the kitchen or warehouse even though the messaging system was down for five minutes.
• A dashboard and alert that tell the team something is wrong before customers start complaining.

What you'll be able to do

By the end of the path you will be able to:

1. PO1 Design APIs that last: resources, status codes, problem details, pagination, versions, idempotency and OpenAPI (BE1).
2. PO2 Model data that stays correct with constraints, transactions, safe migrations, and careful money, time and IDs (BE2).
3. PO3 Find and fix slow queries with query plans, indexes, N+1 fixes and connection pools, and know when to scale the database (BE3).
4. PO4 Cache with Redis correctly: time-to-live, invalidation, stampede protection and a safe fallback when Redis is down (BE4).
5. PO5 Add sign-in with OAuth 2 and OpenID Connect, and verify access tokens properly in an API (BE5).
6. PO6 Protect an API against the OWASP API Security Top 10: ownership, validation, rate limits, secrets and personal data (BE6).
7. PO7 Pass work between services through streams and queues with an outbox, idempotent consumers and dead letters (BE7).
8. PO8 Decide when to split services, use gateways, and keep services up with timeouts, retries, breakers and stateless copies (BE8).
9. PO9 Test with real dependencies, keep contracts between services, observe a live system and release changes safely (BE9).
10. PO10 Combine all of this in three tested projects and a capstone on the TiffinBox practice kit (BE10).

The coverage of each outcome by lessons, quizzes and the path test is listed at the end of this guide.

How it compares with neighbouring paths

The difference in one line: other paths design the screens, run the platform or analyse the data; this path builds the server-side logic and data that everything else relies on, and proves it stays correct under load and failure.

Before you start: core lessons to know

The path opens after you pass the final examination. These core modules matter most; revisit them if the entry diagnostic shows a gap:

Setup guide

Tested on 1 November 2026 on Linux. Versions change, so check each tool's official page when you install. The practice kit pins exact package versions in its package.json, so npm install gives you the same ones.

Install:

1. Install Node.js 22 LTS from nodejs.org. Check: node -v prints v22... and npm -v prints a version.
2. Install PostgreSQL 16 and Redis 7 from their official sites or your system's package manager (on Windows, Redis runs well inside WSL). Or, if you use Docker, run docker compose up -d in the kit folder.
3. Download the starter kit from this path's Projects page and unzip it. In a terminal, go to the tiffinbox folder.
4. Create the practice database user and database, as shown in tiffinbox/README.md, then run npm install and npm run db:setup (about 10 seconds).
5. Run npm run sim and npm run api in two terminals, and open http://localhost:4000/health. You should see {"status":"ok","db":true,"redis":true}.

Verify your setup: run npm test. In the starter most tests fail on purpose (5 of 29 pass); what matters is that the test runner starts, lists 29 tests and finishes. The queue tests stop services and cut Redis on purpose, so the whole run takes a few minutes.

Windows and macOS: we could only verify Linux on 1 November 2026 (both with locally installed services and with the kit's Docker file), so Windows and macOS are marked "not verified" in the kit. Commands that put a setting before npm run (such as RATE_LIMIT=40 npm run api) are for Linux and macOS; the kit's README gives the PowerShell form.

Hardware and accounts

• Computer: a laptop from the last 6 to 8 years with 8 GB of memory and about 2 GB of free disk space. 4 GB works, but running PostgreSQL, Redis and four services at once is slow.

• No paid accounts are needed. The kit's kitchens, customers and orders are generated, and its sign-in server is a practice one with test users and no passwords. Nothing is charged or sent anywhere. It behaves like a typical identity provider for these tests, but passing them doesn't prove a real provider, payment service or production deployment works.

• Optional: a GitHub account for CI (BE9), and a cloud free tier if you want to try a real managed database. Neither is needed to pass.

Workload

Times are realistic estimates for a learner who has finished the core programme. They are not measured averages.

At 8 to 10 hours a week that is about 13 to 17 weeks.

How completion works

You complete the path when all of these are true, as shown on your completion record:

• every lesson is marked done;
• every module quiz is passed (70% or more);
• the path test is passed (70% or more);
• the three projects and the capstone are self-checked complete, with evidence links and your explanations.

Projects are self-checked for now: you tick the marking guide yourself and save your evidence on this device. Review by a team is planned for later; until then nothing on this site says a reviewer has approved your work. Progress is saved in this browser only, so download a backup from My progress now and then.

Outcome coverage