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 Sandboxes & Code Execution

The 2 Best E2B Alternatives in 2026

Name: App Stack Builder
Availability: InStock

Looking for an alternative to E2B? Below we compare the best agent sandboxes & code execution alternatives by pricing, free tiers, and what each is best for — so you can pick the right fit for your budget and stack.

Why look for a E2B alternative?

E2B is a solid agent sandboxes & code execution choice, but it isn't the right fit for everyone. The most common reasons teams evaluate alternatives:

−$150/month before any compute on the first paid tier
−Hobby sessions cap at one hour
−Usage billing on top of the plan makes costs harder to forecast

E2B vs Alternatives — Quick Comparison

Tool	Pricing	Rating	Best for
E2BYou searched	Free · paid from $150/mo	4.6	Agent Sandboxes & Code Execution — sandbox, agents
1.Modal	Free · paid from $250/mo	4.7	Agent Sandboxes & Code Execution — sandbox, serverless
2.Vercel Sandbox	Free · then usage-based	4.5	Agent Sandboxes & Code Execution — sandbox, firecracker

Top E2B Alternatives, Explained

1. Modal

Free tier4.7· Free · paid from $250/mo

Modal lets you define infrastructure in Python and run it on demand: functions, batch jobs, web endpoints, GPU inference and, increasingly, sandboxes for agent-generated code. It sits in this category because its Sandbox API runs untrusted code in isolated containers billed by the second, at $0.00003942 per core-second and $0.00000667 per GiB-second. The same account can reach GPUs from T4s up to B200s when an agent needs one. Starter is $0 plus compute, with $30/month free and 3 seats. Team is $250/month plus compute, with $100 of credit and unlimited seats.

Sandboxes, GPUs and jobs on one platform and one bill
Infrastructure as Python, with no YAML or Dockerfiles required
$30/month free covers a lot of prototyping

Modal pricing & review E2B vs Modal

2. Vercel Sandbox

Free tier4.5· Free · then usage-based

Vercel Sandbox runs each session in an isolated Firecracker microVM, in 19 regions, with up to 8 vCPUs and 24-hour sessions on Pro. Its pricing suits agents well. Active CPU is billed only while code is actually executing ($0.128/hour); time spent waiting on an LLM call does not count. Memory is billed as provisioned ($0.0212/GB-hour), and downloads such as npm installs are free. Hobby includes 5 CPU-hours, 420 GB-hours and 5,000 creations a month, with 45-minute sessions and 10 concurrent sandboxes. On Pro, usage draws down the plan's $20 monthly credit first, and concurrency rises to 10,000.

Active-CPU billing: idle time waiting on the model is free
Firecracker isolation with snapshots and persistent drives
Natural fit if the app already runs on Vercel

Vercel Sandbox pricing & review E2B vs Vercel Sandbox

Frequently Asked Questions

What are the best alternatives to E2B in 2026?⌄

The best E2B alternatives in 2026 are Modal, Vercel Sandbox. Each is a agent sandboxes & code execution option you can compare on pricing, free tiers, and features in the table above.

Is there a free alternative to E2B?⌄

Yes — Modal, Vercel Sandbox offer free tiers, making them strong free E2B alternatives for bootstrapped startups.

Why look for a E2B alternative?⌄

A common reason teams switch is $150/month before any compute on the first paid tier. Beyond that, people compare agent sandboxes & code execution tools on pricing, specific feature gaps, ease of use, and whether an open-source or free-tier option exists — so they can pick the best fit for their stack and budget.

What is the cheapest E2B alternative?⌄

Modal is among the most affordable E2B alternatives — free · paid from $250/mo. Check the comparison table above for the full pricing breakdown.

Which E2B alternative is rated highest?⌄

Modal is the highest-rated E2B alternative in our catalog at 4.7 out of 5, making it a strong pick if you want a well-reviewed option.