Salesforce Project Kit: Order Sync Integration with Samarth Ahuja

How do you make sure a retry doesn't create a duplicate? How do you secure a webhook? What happens when the other system is down? These are the questions that decide integration interviews, and they are hard to answer well without having built one. This kit is that build.

What you build

When an order is activated in Salesforce, it is sent to a warehouse's API with an idempotency key, so a timeout or a retry can never ship it twice. Busy or failing calls back off and retry, and a transaction finalizer cleans up after a job that dies. The carrier's shipment updates arrive through a public webhook that checks an HMAC signature, ignores duplicates and handles events arriving out of order. An hourly reconciliation catches whatever the webhook missed. Operations watch it all on an Order Sync Monitor built in LWC.

What is in the kit

- The spec: user stories, 17 acceptance criteria, and the warehouse's API and the carrier's webhook as contracts, written like a real ticket

- A starter Salesforce DX project: the data model, named credential, monitor, a warehouse simulator and all 67 tests are ready; you write the ten classes that do the work

- Tests that check your work: each unfinished part fails with a message naming the step that builds it, so you always know what is left and when you are done

- The finished solution: all 67 tests passing, and run end to end in a real org, including a public endpoint called with no login

- A 21-page build guide (PDF): set-up, the design and the reasons behind it, seven build steps, running it in your org, and the lessons found while building it

- Interview notes: a 30-second pitch, a two-minute walkthrough, and 14 questions this project invites, with strong answers

What you will practise

Named and external credentials · Queueable callouts and the callout-before-DML rule · idempotency keys · retries with backoff and Retry-After · transaction finalizers · Apex REST on a public Site · HMAC signatures and replay protection · duplicate and out-of-order events · a scheduled batch that makes callouts · HttpCalloutMock and testing async Apex

Who it is for

Salesforce developers with some Apex who want an integration project that stands up in a product-company interview. It pairs with the free Integrations & APIs course on samarthahuja.org.

What you need

The Salesforce CLI, VS Code, a free Developer Edition org and Node.js. Six to eight hours.

How it works

You get an instant download. Everything is self-paced: the tests check your work, and the finished solution is included if you get stuck. For your own learning and portfolio; please don't share or resell the kit.