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.

AI Evals & Agent TestingFree tier

DeepEval: Pricing, Features & Alternatives

DeepEval lets you write LLM tests the way you write unit tests: assert that an output passes metrics such as answer relevancy, hallucination, tool correctness or task completion, and run them with pytest in CI. It is Apache-2.0 licensed (about 19K GitHub stars) and ships 50+ research-backed metrics, including agent-specific ones. Its maker, Confident AI, hosts results, datasets and tracing: Free for 2 seats and 5 test runs a week, Starter $200/month per organization (unlimited seats, online evals, chat simulations), Team $2,000/month (SSO, SOC 2), and custom Enterprise.

DeepEval Pricing Plans (2026)

Plan	Price	Highlights
Open SourcePopular	$0 (Apache-2.0)	50+ metrics · pytest integration · Agent and RAG metrics
Confident AI Free	$0	2 seats, 1 project · 5 test runs / week · Tracing and datasets
Confident AI Starter	$200 / month per organization	Unlimited seats, 5 projects · Online evals on live traffic · Chat simulations
Confident AI Team	$2,000 / month per organization	Unlimited projects · SSO, RBAC, SOC 2 · Dedicated support

Pricing summary: Free · paid from $200/mo. Always confirm current pricing on the official site.

Key DeepEval Features

50+ metrics
pytest integration
Agent and RAG metrics

Pros

+Feels like unit testing, runs in pytest
+Agent metrics like tool correctness
+Free and open source

Cons

−Hosted platform jumps from $0 to $200 / month
−LLM-judged metrics cost tokens on every run
−Python only

Best DeepEval Alternatives

Compare all

Promptfoo

Free · paid plans by quote

Ragas

Free

Coval

From $100/mo

DeepEval Compared

DeepEval vs Promptfoo DeepEval vs Ragas DeepEval vs Coval

DeepEval FAQ

What is DeepEval used for?⌄

DeepEval is a ai evals & agent testing tool. Open-source, pytest-style framework for unit testing LLM apps and agents, with 50+ metrics. Confident AI is its hosted platform.

Is DeepEval free?⌄

Yes — DeepEval has a free tier you can start with, and paid plans for more usage and features.

How much does DeepEval cost?⌄

DeepEval offers a free tier, with paid plans starting at $200/month.

What are the best DeepEval alternatives?⌄

Popular DeepEval alternatives include Promptfoo, Ragas, Coval. Compare pricing and features on our DeepEval alternatives page.