What is App Stack Builder?

App Stack Builder is a free AI-powered tool that helps founders and developers choose the right tech stack for their projects based on budget, app type, team size, and skill level.

What is the best tech stack for SaaS in 2026?

The best tech stack for SaaS in 2026 typically includes Next.js 16 for frontend, Supabase for database and auth, Vercel for hosting, Stripe for payments, and PostHog for analytics. App Stack Builder can generate a personalized recommendation based on your specific budget and requirements.

Is App Stack Builder free to use?

Yes, App Stack Builder is completely free to use. You can generate unlimited tech stack recommendations without any cost.

What types of apps can I build with the recommended stacks?

App Stack Builder supports various app types including SaaS applications, web apps, mobile apps, e-commerce stores, internal tools, and AI/ML products.

How much does a SaaS tech stack cost per month?

A modern SaaS tech stack can cost anywhere from $0-50/month for bootstrapped startups using free tiers, $100-300/month for growth-stage startups, to $500+/month for enterprise-ready infrastructure. App Stack Builder helps you find the best tools within your specific budget.

What is the best tech stack for solo founders?

For solo founders, we recommend Next.js + Vercel (free), Supabase (free tier), Supabase Auth (free), Stripe (pay as you go), and Plausible or PostHog for analytics. This stack can run your entire SaaS for under $50/month.

Can I export my tech stack recommendations?

Yes, you can export your tech stack recommendations as a PDF document or copy them to your clipboard. You can also share a link to your stack with others.

Auth

Best Authentication Tools for SaaS in 2026

Authentication is security-critical and tedious to build well. Whether you want a drop-in hosted provider or an open-source library you control, here are the best auth tools for startups in 2026.

Auth Tools Compared

Tool	Pricing	Free tier
Clerk	Free · paid from $25/mo
NextAuth.js	Free
SuperTokens	Free · paid from $0.02/mo
Auth0	Free · paid from $35/mo
Firebase Authentication	Free

The Best Auth Tools, Ranked

1. Clerk

Free tier· Free · paid from $25/mo

Complete authentication and user management platform for modern web applications.

Excellent developer experience
Prebuilt auth UI saves time
Strong Next.js and React integration

Clerk & alternatives

2. NextAuth.js

Free tier· Free

Open-source authentication solution for Next.js with built-in providers, sessions, and security best practices.

Completely free and open source
Deep integration with Next.js
No vendor lock-in

NextAuth.js & alternatives

3. SuperTokens

Free tier· Free · paid from $0.02/mo

Open-source authentication solution with flexible cloud and self-hosted options, priced per MAU.

Fully open source option
Very transparent pricing
Strong session management

SuperTokens & alternatives

4. Auth0

Free tier· Free · paid from $35/mo

Enterprise-grade authentication and authorization platform with advanced security, SSO, and identity management.

Enterprise-ready authentication
Highly scalable and reliable
Strong MFA and security features

Auth0 & alternatives

5. Firebase Authentication

Free tier· Free

Authentication service by Google Firebase supporting email/password, phone, social logins, and anonymous auth.

Very easy to set up
Generous free tier
Great for mobile apps

Firebase Authentication & alternatives

How to choose a auth tool

Choose Clerk or Auth0 for polished, drop-in UIs and fast setup.
Pick Supabase Auth or NextAuth if you want tight integration or full control.
Prefer open-source (SuperTokens, NextAuth) to avoid per-MAU pricing surprises.
Confirm support for the methods you need: social, magic links, SSO, MFA.

Frequently Asked Questions

What are the best auth tools for startups in 2026?⌄

The best auth tools for startups in 2026 include Clerk, NextAuth.js, SuperTokens, Auth0, Firebase Authentication. Compare them by pricing, free tiers, and features in the list above.

What is the best free auth tool?⌄

Free auth options include Clerk, NextAuth.js, SuperTokens, Auth0 — all offer a free tier suitable for bootstrapped startups and MVPs.

How do I choose a auth tool?⌄

Start with your budget and team size, prefer tools with a free tier to validate, and make sure your pick integrates with the rest of your stack. App Stack Builder can recommend a complete, budget-aware stack in about 60 seconds.

Need the whole stack, not just auth?

Get a free, AI-powered tech stack — matched to your budget, app type, and team size in 60 seconds.

Build my stack free