better-auth-expert

Name: better-auth-expert
Availability: InStock
Author: tehminanaz

Bridge stateless authentication between Next.js clients and FastAPI servers using JWTs and shared secrets.

1|Updated Dec 4, 2025

Search Tags:#typescript #authentication #fastapi #jwt #nextjs #frontend-backend #typesafety

Ready to run

npx skills add https://github.com/Tehminanaz/Evolution-of-Todo --skill better-auth-expert

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Please help me install this Agent Skill.
Skill: better-auth-expert
Source: https://github.com/Tehminanaz/Evolution-of-Todo/tree/main/.claude/skills/better-auth-expert
Command: npx skills add https://github.com/Tehminanaz/Evolution-of-Todo --skill better-auth-expert

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Stateless, frictionless authentication across a Next.js frontend and a FastAPI backend by using a shared secret to mint and verify tokens, enabling seamless cross-language security without session synchronization.

Core Features & Use Cases

Shared BETTER_AUTH_SECRET to mint tokens on the frontend and verify on the backend.
Stateless verification with JWTs and strict typing across the TypeScript/Python boundary.
Zero-trust security with explicit token validation and DI-based user verification in FastAPI.

Quick Start

Configure a shared BETTER_AUTH_SECRET, implement JWT signing on the Next.js client, verify tokens on FastAPI, and enforce strict typing across the boundary.

Frequently Asked Questions about better-auth-expert

High-intent search queries and answers about installing and using this skill.

FAQPage Schema

How do I implement stateless authentication between a Next.js frontend and a FastAPI backend?▼

Stateless authentication between Next.js and FastAPI is implemented by minting JWTs on the frontend using a shared secret and verifying those tokens on the backend without needing session synchronization.

What's the best way to enforce TypeScript and Python type safety across a frontend-backend authentication boundary?▼

Enforcing type safety across a TypeScript and Python boundary involves establishing strict type contracts for JWT payloads and using dependency injection in FastAPI to validate the token structure securely.

Do I need a shared secret to verify JWTs from Next.js on a FastAPI server?▼

Yes, you need a shared secret like BETTER_AUTH_SECRET to mint JWT tokens on the Next.js client and cryptographically verify those same stateless tokens on the FastAPI server.

How does zero-trust security work with JWT verification in FastAPI?▼

Zero-trust JWT verification in FastAPI works by applying explicit token validation and dependency injection-based user verification for every request, ensuring no implicit trust across the language boundary.

Can I use this stateless token approach without synchronizing user sessions across Next.js and FastAPI?▼

Yes, this approach uses stateless JWTs minted on the frontend and verified on the backend, deliberately eliminating the need for any session synchronization between Next.js and FastAPI.

Why does my FastAPI server reject JWTs signed by the Next.js client?▼

FastAPI rejects Next.js JWTs when the shared BETTER_AUTH_SECRET used for signing on the frontend does not match the secret configured for verification on the backend, breaking the type contract.