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Pulse

A Reddit-style community API in Spring Boot: email-verified signup, stateless JWT auth, communities and posts.

Source on GitHub (opens in a new tab)
Role
Solo: backend engineering
Year
2024
Status
Archived
Type
Backend & APIs
ARCHITECTUREPULSE · BACKEND & APISSIGNUPClientBearer tokenJWT filterHS256 · statelessControllersREST · DTOs in/outServicesDTO mappingMailverification linkMySQLJPA / Hibernate

01Problem

Why it exists

I wanted to build the unglamorous middle of a backend from an empty project: a signup that has to be verified, authentication without server state, and a domain with real relationships between users, communities and posts.

02Approach

How I went about it

A conventionally layered Spring application, kept strict. Controllers accept and return DTOs, services own the transactions, and compile-time mappers translate between the two so persistence entities never leak into the API.

03Architecture

Decisions that shaped it

Diagram aboveRequest path: a stateless filter in front of a layered Spring application.

  1. 01

    Signup is a two-step state

    A new account is stored disabled. A verification token is persisted and emailed as an activation link; Spring Security refuses the login until the link has enabled the account.

  2. 02

    A stateless filter in front of everything

    Login returns a signed token. A once-per-request filter validates it ahead of the standard authentication filter, and every route outside the auth namespace requires it.

  3. 03

    A hard DTO boundary

    MapStruct generates the mapping code at compile time, including derived fields such as the number of posts in a community, so there is no reflection and no hand-written copying.

  4. 04

    A two-stage container build

    Dependencies are resolved in a builder stage and only the packaged jar is copied into the runtime image.

04Build

What it does

  • Signup, account verification and login endpoints
  • Create and list communities, fetch a community by id
  • Create posts; read them by id, by community or by author
  • Not-found and domain errors modelled as explicit exception types
Service
Java 17 · Spring Boot 3.2 · Spring Security · Spring Data JPA
Data
MySQL · Hibernate
Supporting
JJWT · MapStruct · Spring Mail + Thymeleaf · springdoc OpenAPI
Delivery
Docker (multi-stage build) · Maven

05Outcome

Where it stands

It did its job: assembling a Spring Security filter chain by hand is the fastest way to understand one.

What is not there: votes and comments exist as entities and repositories but have no service or endpoint, and the test suite is only the context-load test. I stopped at that point and have left the repository as it was.

Checked against the repository on 11 November 2026