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.

Agent Framework

Best Agent Framework Tools for Startups in 2026

Compare the best agent framework tools for startups and developers in 2026. We’ve rounded up 6 options with pricing, free tiers, and features side by side so you can pick the right fit for your stack and budget.

Agent Framework Tools Compared

Tool	Pricing	Free tier
Vercel AI SDK	Free
LangChain	Free · paid from $39/mo
LangGraph	Free
LlamaIndex	Free
AutoGen	Free
CrewAI	Free

The Best Agent Framework Tools, Ranked

1. Vercel AI SDK

Free tier· Free

Open-source TypeScript toolkit for building AI apps and agents with streaming, tool calling, and any model.

Best DX for TS/React AI apps
Provider-agnostic
Free and open-source

Vercel AI SDK & alternatives

2. LangChain

Free tier· Free · paid from $39/mo

The most popular open-source framework for building LLM apps and agents, with LangSmith for observability.

Largest ecosystem & integrations
Free open-source core
Python and TypeScript

LangChain & alternatives

3. LangGraph

Free tier· Free

Open-source library for building stateful, multi-step agent workflows as graphs — with a managed platform option.

Fine-grained agent control
Great for complex multi-step flows
Open-source

LangGraph & alternatives

4. LlamaIndex

Free tier· Free

Open-source data framework for RAG and agents — connect LLMs to your data, with LlamaCloud for managed pipelines.

Excellent RAG tooling
Strong document parsing (LlamaParse)
Open-source

LlamaIndex & alternatives

5. AutoGen

Free tier· Free

Microsoft's open-source framework for multi-agent conversations and orchestration. Free to use.

Backed by Microsoft Research
Strong multi-agent conversation model
Completely free

AutoGen & alternatives

6. CrewAI

Free tier· Free

Open-source framework for orchestrating role-playing, collaborating multi-agent 'crews' to automate workflows.

Intuitive multi-agent model
Fast to prototype crews
Open-source

CrewAI & alternatives

How to choose a agent framework tool

Start with tools that offer a free tier to validate before you pay.
Match the tool to your team size and skill level.
Compare pricing as you scale — watch for per-seat or usage-based costs.
Prefer tools that integrate cleanly with the rest of your stack.

Frequently Asked Questions

What are the best agent framework tools for startups in 2026?⌄

The best agent framework tools for startups in 2026 include Vercel AI SDK, LangChain, LangGraph, LlamaIndex, AutoGen. Compare them by pricing, free tiers, and features in the list above.

What is the best free agent framework tool?⌄

Free agent framework options include Vercel AI SDK, LangChain, LangGraph, LlamaIndex — all offer a free tier suitable for bootstrapped startups and MVPs.

How do I choose a agent framework 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 agent framework?

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

Build my stack free