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.

AutoGen vs Letta: Which is Better in 2026?

Name: App Stack Builder
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Agent Framework

Choosing between AutoGen and Letta? Both are popular agent framework tools. Below we compare them on pricing, free tiers, features, and pros & cons so you can pick the right fit for your stack.

AutoGen is for: Teams that already run AutoGen and need to maintain it while they plan a move to Microsoft Agent Framework.

Letta is for: Teams building agents that must remember users and context across sessions and restarts, with memory as the core design.

Quick verdict

There’s no single winner; pick on your constraint. Choose AutoGen if you already run AutoGen in production and need it to keep working while you migrate. Choose Letta if your agent must remember users and past sessions over weeks or months.

AutoGen vs Letta — Side by Side

	AutoGen	Letta
Category	Agent Framework	Agent Framework
What it is	Code library: multi-agent conversation framework	Agent server and SDKs: agents with persistent memory
Languages	Python, .NET	Python and TypeScript SDKs
Licence	MIT (code)	Apache 2.0
Managed / paid option	None	Letta API: free tier, Pro $20/month plus usage
Project status	Maintenance mode; successor is Microsoft Agent Framework	Active
Pricing	Free	Free · paid from $20/mo
Starting price	Free tier available	Free tier available
Free tier
Rating	4.4	4.0
Best for	Agent Framework — existing AutoGen projects, migration path	Agent Framework — long-term memory, stateful agents, self-host or hosted

Pros & Cons

AutoGen

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

APIs have shifted between versions
Python-centric

Letta

Memory is the design centre, not an add-on
Agents survive restarts with state intact
Comes from the MemGPT paper

Younger project with a moving API
Memory model is opinionated

Key Features Compared

AutoGen

Multi-agent conversations and group-chat orchestration
Python and .NET libraries
In maintenance mode: bug fixes, security patches and docs only, community-managed
Microsoft Agent Framework 1.0 (April 2026) is the successor, with a migration guide
AG2 is a separate community fork led by AutoGen’s original creators

Letta

Persistent, self-editing agent memory (from the MemGPT research)
Agents keep their state across restarts
Self-hosted server, or the hosted Letta API
Hosted plans: free tier and Pro at $20 a month with pay-as-you-go usage
Letta Code, an open-source coding agent with memory across sessions
Apache 2.0 licence

Choose AutoGen if…

You already run AutoGen in production and need it to keep working while you migrate.
You’re studying multi-agent conversation patterns from the original research project.

AutoGen review & pricing

Choose Letta if…

Your agent must remember users and past sessions over weeks or months.
You want agents that keep state when the process restarts.
You want the choice of self-hosting or a hosted API.

Letta review & pricing

Frequently Asked Questions

Is AutoGen better than Letta?⌄

What is the difference between AutoGen and Letta?⌄

What it is — AutoGen: Code library: multi-agent conversation framework. Letta: Agent server and SDKs: agents with persistent memory. Languages — AutoGen: Python, .NET. Letta: Python and TypeScript SDKs. Licence — AutoGen: MIT (code). Letta: Apache 2.0. Managed / paid option — AutoGen: None. Letta: Letta API: free tier, Pro $20/month plus usage. Project status — AutoGen: Maintenance mode; successor is Microsoft Agent Framework. Letta: Active.

AutoGen vs Letta: which is cheaper?⌄

AutoGen pricing: Free. Letta pricing: Free · paid from $20/mo. Confirm current pricing on each tool's official site, as plans change.

Which is rated higher, AutoGen or Letta?⌄

In our catalog, AutoGen rates 4.4 out of 5 and Letta rates 4.0 out of 5, so AutoGen has a slight edge on reviews.

When should I skip both AutoGen and Letta?⌄

Skip AutoGen if you’re starting a new project. AutoGen gets no new features; Microsoft points new work to Microsoft Agent Framework. Skip Letta if you only need short-lived task agents. A lighter SDK is simpler.

Sources · tool facts checked October 2026