Recommended stack · Optimized for self-hosting

Open-Source SaaS

A self-hostable product stack that keeps every critical runtime component under team control.

Responsibilities: 6
Open source: 6 choices
Self-hostable: 6 choices

What it is for

Combine a content-efficient web framework, a compact TypeScript API, PostgreSQL, application-owned authentication, containers, and an integrated OpenTelemetry-native observability backend. The stack is designed to remain portable across infrastructure providers.

Who should use it

Teams with operational capacity that value portability, inspectable systems, and a credible self-hosting path.

From decision to first build

Start with this stack.

Choose the pieces you want, then copy the build prompt into your coding assistant. No account needed.

Optional capabilities start as “Not needed”. Hosted providers add external dependencies, including to the open-source stack.

Package manager: pnpm. All TypeScript setup, script, and CI instructions use pnpm.

What are you building?

Web application

Astro keeps browser JavaScript deliberate and works well for product surfaces with substantial content and selective interactivity.

Open SourceRead the source ↗

API layer

Fastify provides a focused Node.js HTTP foundation with a mature plugin model and low framework overhead.

Open SourceRead the source ↗

Database

PostgreSQL keeps transactional product data portable and independently operable.

Open SourceRead the source ↗

Authentication

Better Auth provides application-owned identity without requiring a proprietary identity service.

Open SourceRead the source ↗

Packaging and deployment

OCI containers make the runtime explicit and portable across a wide range of infrastructure.

Open SourceRead the source ↗

Observability

SigNoz offers one self-hostable surface for OpenTelemetry traces, metrics, logs, and alerts.

Generous Free TierRead the source ↗

Identity verification (KYC) · Not needed

Identity verification (KYC)

Optional — add only when your product needs this capability.

Billing · Not needed

Billing

Optional — add only when your product needs this capability.

Transactional email · Not needed

Transactional email

Optional — add only when your product needs this capability.

File storage · Not needed

File storage

Optional — add only when your product needs this capability.

Background jobs · Not needed

Background jobs

Optional — add only when your product needs this capability.

Product analytics · Not needed

Product analytics

Optional — add only when your product needs this capability.

API contracts · Not needed

API contracts

Optional — add only when your product needs this capability.

Monorepo tooling · Not needed

Monorepo tooling

Optional — add only when your product needs this capability.

Agent integration · Not needed

Agent integration

Optional — add only when your product needs this capability.

Agent instructions · Not needed

Agent instructions

Optional — add only when your product needs this capability.

AI example · Not needed

AI example

Optional — add only when your product needs this capability.

CRUD example · Not needed

CRUD example

Optional — add only when your product needs this capability.

Data access / ORM · Not needed

Data access / ORM

Optional — add only when your product needs this capability.

Database hosting · Not needed

Database hosting

Optional — add only when your product needs this capability.

# Build with Open-Source SaaS

Product brief: A self-hostable product stack that keeps every critical runtime component under team control.
Target user: Teams with operational capacity that value portability, inspectable systems, and a credible self-hosting path.

## Selected technologies
- Language: TypeScript with strict checking.
- Package manager: pnpm (required). Use pnpm, not npm, npx, Yarn or Bun package-manager commands, for installation, scaffolding, scripts, examples, documentation and CI. Pin a compatible pnpm version in package.json packageManager, commit pnpm-lock.yaml, and use pnpm install --frozen-lockfile in CI. Use pnpm add, pnpm exec and the pinned version’s supported pnpm scaffolding command. Preserve existing work; do not delete or replace another lockfile without explicit migration approval.
- Package-manager reference: https://pnpm.io/installation
- Web application: Astro
  Integration: Astro keeps browser JavaScript deliberate and works well for product surfaces with substantial content and selective interactivity.
  Cost context: Open Source
  Reference: https://howtobuild.dev/projects/astro
- API layer: Fastify
  Integration: Fastify provides a focused Node.js HTTP foundation with a mature plugin model and low framework overhead.
  Cost context: Open Source
  Reference: https://howtobuild.dev/projects/fastify
- Database: PostgreSQL
  Integration: PostgreSQL keeps transactional product data portable and independently operable.
  Cost context: Open Source
  Reference: https://howtobuild.dev/projects/postgresql
- Authentication: Better Auth
  Integration: Better Auth provides application-owned identity without requiring a proprietary identity service.
  Cost context: Open Source
  Reference: https://howtobuild.dev/projects/better-auth
- Packaging and deployment: Docker Engine
  Integration: OCI containers make the runtime explicit and portable across a wide range of infrastructure.
  Cost context: Open Source
  Reference: https://howtobuild.dev/projects/docker
- Observability: SigNoz
  Integration: SigNoz offers one self-hostable surface for OpenTelemetry traces, metrics, logs, and alerts.
  Cost context: Generous Free Tier
  Reference: https://howtobuild.dev/projects/signoz

## Implementation brief
1. Inspect the current repository and its instructions. Explain the architecture and verify the current official installation guides and package compatibility for the selected choices. Preserve existing work.
2. Implement one useful vertical slice with a responsive, accessible interface, loading/empty/error states, and a clear README. Use only the selected provider for each responsibility. Do not silently substitute another stack.
3. If authentication is selected, enforce authorization on the server. Implement sign-in, sign-out, session handling, and protected data access. Keep provider secrets server-side and document required environment variables.
4. Document data models and migration commands. Do not provision paid services, deploy, or modify an existing database without explicit authorization. Use placeholders in .env.example and never invent API keys.
5. Validate with the repository’s allowed checks and record their results. Document what remains dependent on account setup, credentials, or deployment.
6. Do not add optional providers that were not selected. For external integrations, keep secrets server-side, verify webhook signatures, and make event handling idempotent. Hosted add-ons change the base stack’s self-hosting and cost assumptions.

## Base stack tradeoffs (reassess when a choice is replaced)
- Owning the runtime means owning upgrades, backups, incident response, and capacity planning.
- Astro and a separate API create a clearer boundary but more deployment topology than one full-stack framework.
- Self-hosting is not automatically cheaper once operational time is counted.
- These selections customize the editorial stack. Recheck integration boundaries when replacing a component; hosted free tiers are not a promise of free production operation.

## Stack references
- https://howtobuild.dev/stacks/open-source-saas
- Astro rendering and islands architecture: https://docs.astro.build/en/concepts/islands/
- OpenTelemetry-native observability platform capabilities: https://signoz.io/docs/

Updates as you choose your technologies.

Responsibility map

One choice for each job.

01
Web application
Astro
Astro keeps browser JavaScript deliberate and works well for product surfaces with substantial content and selective interactivity.
Open sourceOpen SourceSelf-hostable
Alternatives
Next.js — Choose Next.js when the product needs a more integrated, React-centered full-stack model.
02
API layer
Fastify
Fastify provides a focused Node.js HTTP foundation with a mature plugin model and low framework overhead.
Open sourceOpen SourceSelf-hostable
03
Database
PostgreSQL
PostgreSQL keeps transactional product data portable and independently operable.
Open sourceOpen SourceSelf-hostable
04
Authentication
Better Auth
Better Auth provides application-owned identity without requiring a proprietary identity service.
Open sourceOpen SourceSelf-hostable
05
Packaging and deployment
Docker Engine
OCI containers make the runtime explicit and portable across a wide range of infrastructure.
Open sourceOpen SourceSelf-hostable
06
Observability
SigNoz
SigNoz offers one self-hostable surface for OpenTelemetry traces, metrics, logs, and alerts.
Open sourceGenerous Free TierSelf-hostable
Alternatives
Prometheus — Choose Prometheus first when metrics and alerting are the immediate need and an integrated platform is premature.

Open-source profile

What you can own.

Every selected component is open source and can run on infrastructure controlled by the team. Individual licenses and trademark terms still need review before redistribution.

Cost profile

Where cost appears.

There are no mandatory software subscription fees, but compute, storage, email delivery, backups, and the labor of operating the stack are real costs.

Tradeoffs

What this stack asks you to accept.

Owning the runtime means owning upgrades, backups, incident response, and capacity planning.
Astro and a separate API create a clearer boundary but more deployment topology than one full-stack framework.
Self-hosting is not automatically cheaper once operational time is counted.

Editorial note

Stack choices are editorial recommendations, not an automatic popularity ranking. Pricing and capabilities can change.

Sources checked

Astro rendering and islands architectureSep 4, 2026

OpenTelemetry-native observability platform capabilitiesSep 4, 2026