100 SaaS Applications resources for developers

The industry standard for recurring revenue. Use Stripe Checkout for pre-built UI and the 'Customer Portal' for self-service subscription management.

A Merchant of Record (MoR) that handles global sales tax and VAT compliance automatically, simplifying international SaaS sales.

Implement a robust webhook listener using the 'stripe-node' library to handle events like 'invoice.paid' and 'customer.subscription.deleted' with idempotency checks.

An open-source alternative to Stripe Billing for complex usage-based pricing models that require high-volume event ingestion.

A monetization platform specifically for open-source developers to sell subscriptions or access to private GitHub repositories.

Another Merchant of Record that provides unified checkout, subscription management, and tax handling globally.

Programmatic tax calculation for custom checkout flows, ensuring you collect the correct sales tax based on the user's jurisdiction.

A pricing-as-code solution that allows you to define pricing plans in a JSON/YAML file and sync them to Stripe automatically.

Essential for SaaS apps with mobile components to manage cross-platform subscriptions and sync Apple/Google IAP state to the web.

High-scale billing infrastructure designed specifically for companies moving to complex, hybrid usage-based pricing models.

Pre-built components and API for team management, allowing users to create, join, and switch between multiple SaaS accounts seamlessly.

Implement multi-tenancy at the database layer by ensuring users can only access data where 'tenant_id' matches their session context.

The fastest way to add SAML and SCIM support for B2B SaaS customers who require integration with Okta or Azure AD.

A flexible framework for self-hosting authentication logic with support for various database adapters like Prisma and Drizzle.

Combines user authentication with built-in feature flagging to control access to specific SaaS tiers based on user roles.

An open-source alternative to Auth0 that focuses on multi-tenancy and high security standards for enterprise-ready SaaS.

B2B-specific authentication that handles organization management and invites out of the box, reducing custom code for team logic.

Define permissions in a central location (e.g., 'can edit post') and share them between your frontend and backend logic.

A lightweight, stateless session utility for Next.js that uses encrypted cookies to store user data without a server-side session store.

Advanced isolation technique using separate Postgres schemas for each customer, suitable for high-security or regulated industries.

An all-in-one suite for session recording, heatmaps, and feature flags to understand how users interact with your SaaS.

An LLM proxy that provides caching, rate limiting, and cost tracking for OpenAI and Anthropic API calls to prevent budget overruns.

A developer-first email API for sending welcome emails, password resets, and notifications with a clean React-based template engine.

Real-time error tracking that includes stack traces and breadcrumbs, essential for maintaining SaaS uptime and reliability.

Use serverless Redis to implement API rate limiting per user or per tenant to protect your infrastructure from abuse.

A serverless queue and workflow engine that allows you to handle long-running tasks like CSV exports or AI processing without timeouts.

An email platform built for SaaS that triggers automated onboarding sequences based on user events from your app.

A service that helps you send webhooks to your own customers, handling retries and security signatures automatically.

A unified interface to call 100+ LLMs using the OpenAI format, allowing you to swap providers easily to reduce costs.

High-performance log management for Vercel and serverless environments, providing instant insights into system behavior.