---
title: "Designing an Identity Provider for a Developer Community"
description: "Lessons from building 48ID — an API-first IDaaS with OAuth2, JWT issuance, RBAC, and SSO for the K48 ecosystem."
date: "2026-05-24"
tags: ["OAuth2", "Spring Boot", "Identity", "Architecture"]
published: true
---

Fragmented authentication is one of the quietest sources of friction in a
multi-app ecosystem. Every new app reinvents login, sessions, and roles — and
each one does it slightly differently. **48ID** exists to remove that tax.

## The goal

One trust anchor that every app in the K48 ecosystem can rely on:

- Centralized identity and user records
- Standards-based token issuance (OAuth2 + OpenID Connect, JWT)
- Role-based access control (RBAC)
- Single sign-on across apps like 48Hub

## Why API-first

Treating the identity provider as a product with a clean API — rather than a
library bolted onto one app — means new student projects can integrate auth in
**less than a day** instead of rebuilding it from scratch.

```http
POST /oauth2/token
Content-Type: application/x-www-form-urlencoded

grant_type=authorization_code&code=...&client_id=48hub
```

## The stack

The service runs on **Spring Boot 3** with **Spring Modulith** to keep
boundaries clean, **PostgreSQL** for persistence, and **Redis** for sessions
and short-lived tokens. The admin portal is a **Next.js 16** BFF.

> The hard part of identity isn't the crypto — it's the boundaries. Decide early
> what is a session, what is a token, and who is allowed to mint each one.

If you're building something similar, start with the token lifecycle on paper
before you write a line of code. Everything else follows from it.