Deflated.fyi — Crowdsourced Inflation Tracker

A Go backend + React frontend for tracking real grocery prices over time, aggregated from user-submitted receipts.

Project structure

deflated/
├── cmd/server/main.go          # Entrypoint — starts HTTP server
├── internal/
│   ├── api/
│   │   ├── router.go           # Chi router, all routes registered here
│   │   └── handlers.go         # One handler per endpoint
│   ├── db/
│   │   ├── connect.go          # pgxpool setup
│   │   └── queries.go          # All SQL queries as typed Go methods
│   ├── models/
│   │   └── models.go           # Shared structs (DB rows, API shapes)
│   ├── parser/
│   │   └── normalize.go        # Receipt item → canonical name
│   └── inflation/
│       └── worker.go           # Background job: refresh price snapshots
├── migrations/
│   └── 001_initial.sql         # Database schema
├── .env.example                # Copy to .env, fill in values
├── Makefile                    # make run / test / migrate
└── go.mod

Prerequisites

• Go 1.23+
• PostgreSQL 15+

Quick start

# 1. Clone and enter the project
git clone https://github.com/yourname/deflated
cd deflated

# 2. Set up environment
cp .env.example .env
# Edit .env with your DATABASE_URL

# 3. Create the database
createdb deflated
make migrate

# 4. Install dependencies and run
go mod tidy
make run

Server starts on http://localhost:8080

API

Method	Path	Description
GET	/health	Health check
POST	/api/receipts	Submit a receipt with line items
GET	/api/receipts/:id	Get a receipt and its items
GET	/api/items/:name/history	Price history for a canonical item
GET	/api/items/movers	Top price movers (last 12 months)
GET	/api/inflation/summary	Purchasing power summary

Submit a receipt

curl -X POST http://localhost:8080/api/receipts \
  -H "Content-Type: application/json" \
  -d '{
    "store_name": "Trader Joes",
    "receipt_date": "2024-11-15",
    "city": "Austin, TX",
    "items": [
      { "name": "Whole Milk 1 Gallon", "price": 4.29 },
      { "name": "Large Eggs Dozen",    "price": 3.49 },
      { "name": "White Bread Loaf",    "price": 2.99, "quantity": 1 }
    ]
  }'

Go learning path

This project is intentionally structured to teach Go incrementally:

1. cmd/server/main.go — entry point, signals, graceful shutdown
2. internal/db/connect.go — connection pools, context, timeouts
3. internal/api/router.go — Chi router, middleware
4. internal/api/handlers.go — request parsing, error handling, JSON responses
5. internal/db/queries.go — raw SQL with pgx, scanning rows into structs
6. internal/parser/normalize.go — pure functions, string processing
7. internal/inflation/worker.go — goroutines, channels, context cancellation

Read the files in that order and you'll have covered ~80% of idiomatic Go.