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$
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I will add jwt or oauth2 authentication to your spring boot app
Ezzat Mohamed
About this gig
Authentication is the part of a backend that's easy to get working and easy to get wrong. It's what I specialise in.
WHAT I DO
- JWT login, token validation, refresh tokens
- Role and permission based access control
- Integrate an identity provider: Keycloak, Auth0, Cognito, Okta
- Fix a Spring Security setup returning 401 or 403 that nobody can explain
- Multi-tenant isolation, so one customer can never see another's data
- Security review of an auth setup you already have
WHY ME FOR THIS SPECIFICALLY
Most developers have configured Spring Security. I've built the server that issues the tokens.
github.com/ezat141/authcore is a full OAuth2 / OpenID Connect authorization server: multi-tenant, signing keys that rotate with zero downtime, and refresh-token reuse detection that kills a stolen token's entire family. 65 tests against real PostgreSQL and Redis.
Clone it. It runs in about two minutes. Judge the work before you order.
For business applications. I don't take academic assignments.
Tell me what you have now and what you need, and I'll tell you honestly what it takes.
Get to know Ezzat Mohamed
Ezzat Mohamed
Java Spring Boot Backend Developer
- FromEgypt
- Member sinceAug 2026
Languages
Arabic, English
I'm a Java backend developer. I build Spring Boot REST APIs and fix broken ones, and my specialty is API security: JWT, OAuth2, roles and permissions, multi-tenant systems.
Most of my work is on banking and payment systems, where a bug is a financial event rather than a ticket. So I reproduce a problem before I touch it, and I write a test that proves it is fixed.
You don't have to take my word for it. My code is public: github.com/ezat141/authcore is a full OAuth2 server with 65 tests that you can clone and run in two minutes.
I work with businesses. I don't take academic assignments.
Other Software Development Services I Offer
FAQ
Is JWT actually secure? I've read conflicting things.
JWT is fine when implemented properly — the problems come from short-cuts: no expiry, no signature verification, secrets in source control, or refresh tokens that never rotate. I'll tell you which of those apply to your setup and fix them.
Should I use my own auth or something like Auth0?
Depends on your situation, and I'll give you a straight answer rather than the one that bills more. If you need social login, SSO, or MFA soon, an identity provider is usually cheaper overall. If you just need email-and-password with roles, building it into your app is simpler and has no per-user co
Can you review my existing auth without changing anything?
Yes — that's the security review extra. You get a written report of what I found, ranked by severity, with a fixed quote to fix each item. No code changes unless you ask for them.
Will this work with my frontend?
Yes. JWT auth is frontend-agnostic — React, Angular, Vue, mobile, or another backend all consume it the same way. I'll include example requests showing exactly how to log in and call a protected endpoint.
