System design builds
Kindling (Tinder, second take)
A second Tinder-style build using PostGIS and an SNS-to-SQS pipeline for live match events.
Problem
This folder was meant for an online auction build, but the prompt linked the Tinder breakdown, so it became a second, independent take on Tinder. Comparing it with Spark shows how two runs of the same brief can choose different architectures.
How it differs from Spark
| Spark | Kindling | |
|---|---|---|
| Geo search | OpenSearch | PostGIS |
| Match events | Redis pub/sub | SNS → SQS (+DLQ) → consumer → Redis pub/sub → SSE |
| Durable swipe log | DynamoDB | DynamoDB |
Tech stack
| Layer | Choice |
|---|---|
| Frontend | Next.js 16 (BFF + UI) |
| Backend | Spring Boot 4 / Java 25 |
| Data | PostgreSQL + PostGIS, Redis/Valkey, DynamoDB, SNS/SQS |
| Infra | LocalStack locally; Terraform to ECS Fargate |
Open questions
- Build the online auction that was originally intended, using the Hello Interview online auction breakdown.
Changelog
- 2026-09-26: Built, TODOs finished, pushed to GitHub