HTMX + Flask

The ecosystem-standard session-management extension for Flask. It handles login sessions and "remember me" cookies, but ships with no user model, password hashing, or registration flow of its own, so you're still wiring those up yourself. The default here because it's the lightest-weight, most Flask-idiomatic starting point.

A hosted identity platform with an official Python SDK for verifying sessions in Flask route handlers, worth it over Flask-Login if you'd rather not build the user model, password hashing, and registration flow yourself.

A transactional email API for account verification, password resets, and notification emails, sent via Resend's official Python SDK from a Flask route handler, with a free tier for getting started.

The established high-volume choice, with dedicated IP addresses and deliverability tooling for apps sending at serious scale. No permanent free plan (a 60-day trial, then paid tiers), so it earns its slot when volume and deliverability matter more than upfront cost.

An all-in-one platform combining the transactional email API with marketing campaigns, a built-in CRM, and SMS from the same dashboard. A permanent free tier of 300 emails a day with no card required makes it an easy starting pick for an early-stage app.

Adds subscription billing, one-time checkout, and invoicing via Stripe's hosted Checkout or embedded Elements, with Flask handling webhook verification and API calls server-side. The stack works fully without it; add this once the product is ready to charge for something.

A utility-class CSS framework: styles are composed directly in markup via class names instead of writing separate stylesheet files. The default styling choice bundled by most modern framework CLIs (create-next-app, create-vue, the SvelteKit and Astro starters all offer it), and the base layer shadcn/ui components are built on when that's loaded into the catalog in the future.

Ready-made components and a grid for Jinja2 templates, loaded from a CDN or installed with a Flask extension such as Bootstrap-Flask, which adds macros for forms, tables, and pagination. A quick route to a conventional interface with little CSS to write. Pick it or Tailwind, not both.

Alpine.js adds lightweight, declarative client-side interactivity on top of this stack's HTMX-driven Flask pages: toggling a mobile menu, showing a modal, or switching an active tab, all without triggering a server round trip HTMX would otherwise need. It is included via a script tag, with behavior written as HTML attributes (x-data, x-show, x-on) rather than a build step, keeping the stack's zero-bundler approach intact.

S3-compatible object storage with no egress fees, so serving uploads, images, and exports costs only for storage and operations. Flask has no built-in file store, so a route uses boto3 to write the file or hand the browser a presigned URL, and the keys stay in the app's environment. The 10 GB free tier covers an early product.

The reference object store and the API the others copy, with the most storage classes, regional controls, and lifecycle rules. Flask has no built-in file store, so a route uses boto3 to write the file or hand the browser a presigned URL, and the keys stay in the app's environment. It fits best when the rest of the app already runs on AWS, though data transfer out is billed.

An S3-compatible store at roughly a third of S3 Standard's storage price, a fit for backups and large media libraries. Flask has no built-in file store, so a route uses boto3 to write the file or hand the browser a presigned URL, and the keys stay in the app's environment. Egress is free up to three times the stored data, and a CDN in front of a public bucket covers heavier delivery.

Runs the test suite and triggers deployments on every push, directly from the same GitHub repo the code already lives in, with no separate CI service to configure.

GitLab's built-in CI/CD system, configured via .gitlab-ci.yml in the repository, the natural pick if the project's code lives on GitLab (self-hosted or gitlab.com) rather than GitHub, with the same YAML-pipeline model as GitHub Actions.

Packages the whole Flask + HTMX app into a container image for consistent local development and deployment, independent of the hosting platform chosen above.

An all-in-one product analytics platform: event tracking, session replay, feature flags, and A/B testing in one SDK. The richest feature set if you want more than pageviews.

The industry-standard, free analytics platform, with native Google Ads and Search Console integration. Requires a cookie consent banner in most jurisdictions (GDPR/CCPA), and all data lives on Google's infrastructure, the tradeoff the other three picks were built to avoid.

A lightweight, privacy-first analytics tool with no cookie banner required. A good fit for simple traffic metrics without PostHog's broader feature surface.

Open-source and self-hostable, keeping analytics data on infrastructure you control. Pairs naturally with the self-hosted Hetzner hosting option above if you want to avoid a third-party analytics vendor entirely.