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.

Fly.io vs Heroku: Which is Better in 2026?

Name: App Stack Builder
Availability: InStock

Hosting

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

Fly.io is for: Developers who want to run containers in many regions near their users and are comfortable working from a CLI.

Heroku is for: Teams that want the original git-push PaaS with buildpacks for many languages and a large add-on marketplace.

Quick verdict

There’s no single winner; pick on your constraint. Choose Fly.io if your users are spread across continents and latency matters. Choose Heroku if you want buildpacks that detect your language and build without a Dockerfile.

Fly.io vs Heroku — Side by Side

	Fly.io	Heroku
Category	Hosting	Hosting
What it is	Global container platform	Managed platform as a service (PaaS)
How you pay	Per second while machines run	Fixed monthly price per dyno
Free access	$1 trial; invoices under $5 waived	None; Eco dynos from $5 a month
What it runs	Any Docker image; managed Postgres	Web and worker dynos in most languages; Postgres, Key-Value
Who runs the servers	Managed hardware; you configure machines and regions	Fully managed
Pricing	Usage-based	From $5/mo
Starting price	Pay-as-you-go	From $5/mo
Free tier	—	—
Rating	4.7	4.2
Best for	Hosting — multi-region, Docker, low latency	Hosting — git-push deploys, buildpacks, add-on marketplace

Pros & Cons

Fly.io

True global, multi-region deployments
Excellent latency for global users
Transparent usage-based pricing
Strong Postgres and networking story
Developer-centric tooling

Steeper learning curve than Vercel/Render
No traditional UI-first workflow
Costs require monitoring at scale

Heroku

Dead-simple git-push deploys
Language-agnostic buildpacks
Rich add-on marketplace
Mature and reliable

No free tier since 2022
Expensive at scale
Eco dynos sleep when idle
Slower innovation under Salesforce

Key Features Compared

Fly.io

Machines billed per second while running; the smallest is $2.19 a month in US East
17 regions, priced by a regional multiplier
Managed Postgres from $38 a month
Egress from $0.02 per GB in North America and Europe
$1 free trial with no card; invoices under $5 are waived
Paid support from $29 a month

Heroku

Eco dynos $5 a month; they sleep after 30 minutes idle
Basic dynos $7 a month, always on
Standard-1X $25 and Standard-2X $50 a month
Heroku Postgres from $5 a month (Essential-0)
Fir, a Kubernetes-based generation, from $25 a month in Private Spaces
No free tier

Choose Fly.io if…

Your users are spread across continents and latency matters.
You want to run any Docker image, not just a supported runtime.
Your app is small, so a monthly bill under $5 is waived.

Fly.io review & pricing

Choose Heroku if…

You want buildpacks that detect your language and build without a Dockerfile.
You rely on Heroku add-ons for databases, logging or email.
Your company already buys Salesforce, which owns Heroku.

Heroku review & pricing

Frequently Asked Questions

Is Fly.io better than Heroku?⌄

What is the difference between Fly.io and Heroku?⌄

What it is — Fly.io: Global container platform. Heroku: Managed platform as a service (PaaS). How you pay — Fly.io: Per second while machines run. Heroku: Fixed monthly price per dyno. Free access — Fly.io: $1 trial; invoices under $5 waived. Heroku: None; Eco dynos from $5 a month. What it runs — Fly.io: Any Docker image; managed Postgres. Heroku: Web and worker dynos in most languages; Postgres, Key-Value. Who runs the servers — Fly.io: Managed hardware; you configure machines and regions. Heroku: Fully managed.

Fly.io vs Heroku: which is cheaper?⌄

Fly.io pricing: Usage-based. Heroku pricing: From $5/mo. Confirm current pricing on each tool's official site, as plans change.

Which is rated higher, Fly.io or Heroku?⌄

In our catalog, Fly.io rates 4.7 out of 5 and Heroku rates 4.2 out of 5, so Fly.io has a slight edge on reviews.

When should I skip both Fly.io and Heroku?⌄

Skip Fly.io if you prefer a dashboard to a CLI. Render and Railway are UI-first. Skip Heroku if you want a free plan. Render, Railway and Netlify have one.

Sources · tool facts checked November 2026