- The situation at Tallow & Thread
- Your role and the brief
- Environment and setup
Make a flash-sale order API survive its first traffic spike
Tallow & Thread’s order-status endpoint is fine in testing and falls over on sale day. You build the service from supplied files, reproduce the failure with a load test, find three separate causes with measurements instead of guesses, fix them one at a time, and add tests that fail if anyone brings the problem back.
PCREATED BYPrepmeetsProject studio, Prepmeets
THE CHALLENGE → YOUR OUTCOME
Real context. Work that matters.
Tallow & Thread’s sale starts on Friday and customers refresh their order page constantly. You are handed an API that works in demos. You build it locally, reproduce the failure under load, find out why with a query plan, a profile and a look at the provider call, fix it in three measured steps, and leave tests that keep it fixed.
What’s at stake
Your responsibility: Work as the backend engineer on the orders team—investigate the requirements, implement your approach and verify the result.A small Node service backs the “where is my order?” page and the operations dashboard. It was written for ordinary weeks. On last year’s sale the page spun for customers, the dashboard froze for staff and the on-call engineer restarted the process four times in an hour. Nobody could say which of the three or four suspicious things was the cause, so on the Monday three of them were “fixed” at once, and nobody knows which one mattered.
Success means: A service that holds a 99th percentile close to its floor under 50 concurrent callers, degrades gracefully when the provider hangs, answers the dashboard without stalling anyone else, and ships with tests that fail if any of the causes comes back. Explain the decisions and checks behind your implementation.
WHAT YOU’LL BUILD
01Node.js
02Express
03SQLite
Tallow & Thread order-status API
INCLUDED WITH YOUR PROJECT
A workspace, not just a document.
Your brief, a Jira-style task board and an interview studio—all in one place.
A look inside your workspace
Start with the full project brief
Build step by step Track your progress Own your interview story
Know where you’re heading.
- 01The situation at Tallow & Thread
- 02Your role and the brief
- 03Environment and setup
- 04Where the time goes
- 05Build, diagnose, fix, prove
- 06Break it on purpose
- 07What you hand over
- 08Submission and cleanup
Practise explaining your decisions
Which decision mattered most in your solution, and how did you verify it?
Use your own implementation to connect Situation, Task, Action and Result into one interview story.
Before you begin · tools & running costs
Prerequisites: Your own accounts and access to autocannon 7, SQLite EXPLAIN QUERY PLAN, Node.js --cpu-prof, node:test.
Additional costs: Cloud and tool usage in your own accounts may incur charges. Set a budget and clean up after testing.
Work in your own accounts and repositories. Never share credentials or confidential data.
What’s included
Project brief, target-design guidance, assigned tasks, resource guidance and interview prompts. Detailed requirements become part of your purchased workspace.
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MEET YOUR PROJECT EXPERT
Prepmeets
Project studio, PrepmeetsWe are the team that builds Prepmeets. Between us we have run cloud platforms, delivery pipelines, analytics teams and AI governance programmes in banks, hospitals, retailers and government departments, and these projects are the work we used to hand to new joiners in their first fortnight. Every one of them is a real scenario with the client’s name changed, scoped to a week of evenings, and reviewed by the person who originally did the job.
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