Your portfolio project: a production-style Go API

Why a portfolio project matters

Go jobs for freshers are fewer than Java or Python jobs, so you must stand out. A clean Go repository proves you can use what interviewers ask about: HTTP handlers, JSON, SQL, errors, tests, concurrency and Docker. It also gives you real stories for "tell me about a challenge you faced" questions.

Pick one project

The URL shortener, step by step

1. Design the API: POST /v1/links {"url": "..."} returns {"code": "aZ3", "short_url": "..."}; GET /{code} redirects with 302; GET /v1/links/{code}/stats returns the click count.
2. Create the table: id BIGSERIAL, code TEXT UNIQUE, url TEXT, clicks BIGINT, created_at TIMESTAMPTZ.
3. Generate codes by base62-encoding the database id (short and unique), or random codes with a retry on conflict.
4. Validate URLs with net/url (scheme must be http or https) and limit their length.
5. Write handlers, middleware (logging, recovery, request ID) and a Store interface with a PostgreSQL implementation.
6. Write table-driven tests for base62 and validation, and httptest tests for handlers using a fake store.
7. Add config from env, graceful shutdown, /healthz and /readyz.
8. Add a multi-stage Dockerfile and a docker-compose.yml that starts the API and PostgreSQL together.
9. Add CI (below), a README with curl examples, and a short "design decisions" section.

const alphabet = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"

// base62 turns a positive id into a short code: 125 -> "21", 62 -> "10".
func base62(n uint64) string {
	if n == 0 {
		return "0"
	}
	var b []byte
	for n > 0 {
		b = append(b, alphabet[n%62])
		n /= 62
	}
	slices.Reverse(b)
	return string(b)
}

CI with GitHub Actions

name: ci
on: [push, pull_request]
jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-go@v5
        with:
          go-version: stable
      - run: go vet ./...
      - run: go test -race -cover ./...
      - run: go build ./...

A README that sells your work

• One paragraph: what it does and the tech used (Go, net/http, PostgreSQL, Docker).
• How to run it in one command: docker compose up.
• curl examples for every endpoint, with real responses.
• A simple architecture sketch: handler → service → store → PostgreSQL.
• Design decisions: why base62 ids, why 302 not 301, how you avoided SQL injection, what you would do for 10x traffic (caching, read replicas).
• What you tested and how (go test -race -cover).

What interviewers check in your repo