What Is a Tech Stack? How to Choose the Best Tech Stack for a Web App, SaaS Product or Startup

Updated September 2026 · Written and maintained by the Progression Agency strategy team

A tech stack is the set of languages, frameworks, databases, services and hosting that a website or application is built and run on. This guide explains what a tech stack is, walks through each layer with the mainstream options, compares common stacks (MERN, Next.js and PostgreSQL, Django, Laravel, .NET, Rails), and gives a practical method for choosing the best tech stack for a web app, a SaaS product, an ecommerce site or a startup MVP.

What is a tech stack?

The term comes from the layers stacking on top of one another: the user sees the front end, which talks to the back end, which reads and writes a database, all of it running on infrastructure and connected to third-party services. Every website has a stack, even a WordPress site (PHP, MySQL, Apache or Nginx, a theme and plugins). The stack determines what the product can do, how fast it runs, what it costs to host and, most importantly, who can be hired to work on it.

The layers of a modern web tech stack

Front end

The interface in the browser. React (usually with Next.js) is the most common choice, with Vue (Nuxt), Angular and Svelte (SvelteKit) as the alternatives; the Stack Overflow Developer Survey 2024 reports React well ahead in usage. For content sites, Astro or a CMS often replaces an application framework. See React vs Vue vs Angular.

Back end

The server that handles requests, business rules, authentication and integrations. Options follow languages: Node.js (Express, Fastify, NestJS), Python (Django, FastAPI), PHP (Laravel), C# (ASP.NET Core), Java (Spring Boot), Ruby (Rails) and Go. Full-stack JavaScript frameworks such as Next.js blur the line by hosting API routes and server code alongside the front end. See web development frameworks.

Database

PostgreSQL is the default relational database for new products; MySQL and MariaDB remain common, especially with PHP; MongoDB is the usual document database; Redis handles caching and queues; managed options such as Supabase, Neon, PlanetScale and Amazon RDS remove the operations work.

Infrastructure and hosting

Where the code runs: Vercel, Netlify and Cloudflare for front-end and serverless work; AWS, Azure and Google Cloud for anything; DigitalOcean, Hetzner and Render for simpler servers; Docker and Kubernetes for containerized systems. See hosting types compared and Cloudflare vs AWS.

Services and tooling

Authentication (Auth0, Clerk, Supabase Auth), payments (Stripe), email (Postmark, SendGrid), search (Algolia, Meilisearch), analytics (GA4, PostHog), monitoring (Sentry, Datadog), CI/CD (GitHub Actions) and the CMS if content is involved.

Common tech stacks compared

Best tech stack for a web app

For a customer-facing web application with logins, data and workflows: Next.js with TypeScript, a Node.js or Next.js back end (or Django when Python libraries matter), PostgreSQL, Stripe for billing, an auth service, and hosting on Vercel or Cloudflare with a managed database. It is the stack most US developers know, so the product can be staffed for years. See web app development.

Best tech stack for a SaaS product

SaaS adds multi-tenancy, subscription billing, roles, audit logs and uptime obligations. The web-app stack above with PostgreSQL row-level security or a tenant column, Stripe Billing, background jobs (queues), object storage (S3 or R2), monitoring and infrastructure as code covers most B2B SaaS. Heavier products move the back end to containers on AWS or Google Cloud when traffic and compliance demand it. See SaaS development and SaaS hosting.

Best tech stack for a startup MVP

Optimize for speed to learning: Next.js plus a backend-as-a-service (Supabase or Firebase) gives auth, database, storage and functions on day one; Stripe handles payments; Vercel hosts it. Avoid microservices, Kubernetes and custom auth until the product has users. See MVP development.

Best tech stack for ecommerce

Shopify (with Hydrogen or a Next.js storefront for custom front ends) for most stores; WooCommerce on managed WordPress hosting for content-heavy stores that need WordPress; a headless commerce API with Next.js for large or unusual catalogs. See Shopify vs WooCommerce.

Best tech stack for a marketing site or landing pages

WordPress when marketers edit everything; Astro with a headless CMS when speed and custom design lead; Webflow when a design team wants no hosting to manage. See Astro vs Next.js and best CMS platforms.

How to choose a tech stack: a method

1. Write down what the product must do in year one and what it might do in year three.
2. List the people who will build and maintain it, and what they know; hiring pool is the biggest long-term cost.
3. Identify hard requirements: compliance (HIPAA, SOC 2), integrations, real-time features, AI or data workloads, offline use.
4. Choose the back-end language from those constraints, then the framework, then the database.
5. Choose the front end by team size and mobile plans.
6. Choose hosting by traffic, budget and operations capacity, and estimate the monthly cost.
7. Prefer boring, mainstream, well-documented tools; novelty is a cost.
8. Record the decisions and their reasons in the plan so they can be revisited deliberately.

Tech stack mistakes to avoid

• Choosing by what a developer wants to learn rather than what the business can hire for.
• Microservices and Kubernetes before there is load to justify them.
• Mixing three back-end languages in one product.
• A NoSQL database for clearly relational data.
• Ignoring hosting cost until the first large bill.
• Building auth, billing or email from scratch when reliable services exist.

How Progression Agency chooses stacks

We default to TypeScript end to end with Next.js, Node.js, PostgreSQL and Vercel or AWS, add Django when Python libraries or AI work matter, and use WordPress or Astro for content. The stack for each project is written into the proposal with the reasons and the estimated hosting cost. See custom software development and software consulting.

Frequently asked questions