LastSaaS — Free, Open-Source SaaS Boilerplate | Go + React

Free SaaS boilerplate for agents & the AI era

Production-ready auth, billing, multi-tenancy, product analytics, and agentic architecture. Open-source. MIT licensed. Skip months of infrastructure work.

The last SaaS boilerplate you’ll ever need. A complete, production-ready SaaS foundation — multi-tenant auth, Stripe billing, white-label branding, API keys, webhooks, product analytics, DataDog observability, and a full admin interface — built entirely through conversation with Claude Code.


Everything a production SaaS needs — on day one

Every SaaS product needs the same foundation: user accounts, teams, roles, authentication, billing, admin dashboards, branding, API access, usage limits. LastSaaS gives you all of it — production-tested and ready to customize for your specific product.

Authentication & Identity

Email/password, Google/GitHub/Microsoft OAuth, magic link passwordless login, MFA/TOTP with recovery codes, JWT with refresh token rotation, session management, account lockout.

Multi-Tenancy

Tenant isolation, three-tier RBAC (owner/admin/user), team invitations, ownership transfer, per-tenant activity logs. Your customers get their own workspace with their own team.

Stripe Billing

Subscriptions (flat-rate or per-seat), free trials, annual discounts, credit bundles, Stripe Checkout, Billing Portal, multi-currency, automatic tax, promotion codes, PDF invoices, refund/dispute handling.

White-Label Branding

Custom app name, logo, theme colors, fonts, landing page, custom pages, CSS injection, configurable navigation with entitlement gating, media library, and auth page customization.

API Keys & Webhooks

API key auth (admin and user scopes) with SHA-256 hashing. Outgoing webhooks with 19 event types, HMAC-SHA256 signing, delivery tracking, and test events. Built-in API documentation.

Plan Entitlements & Usage

Boolean and numeric entitlements per plan with middleware enforcement. Dual credit buckets (subscription + purchased) with configurable reset policies. Billing status gates for paid features.

Admin Interface

Users, tenants, plans, credit bundles, promotions, branding, API keys, webhooks, announcements, system logs, configuration, messaging, financial metrics, product analytics, CSV export, user impersonation — all in a dark-themed admin UI.

Health & Financial Monitoring

Real-time CPU, memory, disk, HTTP, and MongoDB metrics with 8 time-series charts. Revenue, ARR, DAU, MAU dashboards. Integration health checks for MongoDB, Stripe, Resend, OAuth, and DataDog.

Product Analytics & Telemetry

Conversion funnel (visitor → signup → checkout → paid), SaaS KPIs (MRR, ARR, ARPU, LTV, churn), retention cohort heatmaps, engagement metrics (DAU/WAU/MAU), custom event tracking with Sankey flow visualization and dependency graphs.

MCP Server (Agentic Admin)

Built-in Model Context Protocol server with 26 read-only tools. Let AI assistants query dashboards, users, tenants, financials, logs, health, and more — authenticated via root-tenant API key. Works with Claude Desktop and Claude Code.

Security

CSP, HSTS, security headers, rate limiting, NoSQL injection protection, XSS sanitization, webhook signature verification, idempotent event processing, trusted proxy IP resolution, log injection detection.

DataDog Integration

Optional, zero-config DataDog observability. Just add an API key and get health metrics (CPU, memory, HTTP latency), structured logs, service checks for all integrations, and events — all with canonical hostnames and app-prefixed metric names. No DataDog Agent required.

Production Ready

Docker multi-stage build into a 14MB Alpine container. Fly.io deployment with auto-stop/start. SPA served from the Go binary. Auto-versioning with database migrations. CLI administration tools.


Live in production: built on LastSaaS

Want to see a live SaaS application running on LastSaaS? Try Flipbook — a presentation hosting platform built on top of this exact foundation.

Try Flipbook

v1.3 — March 5, 2026

DataDog observability, event flow visualization, and platform hardening. Read the full version notes →


Free vs. paid: how LastSaaS compares to ShipFast, Supastarter, and MakerKit

Most SaaS boilerplates charge hundreds of dollars and still leave you missing critical features. LastSaaS is free, open-source, and ships with everything you need out of the box.

Feature LastSaaS ShipFast Supastarter MakerKit Pegasus Gravity
Price Free (MIT) $169 $299+ $199–599 $249/yr <$1K
Open Source
Stack Go + React Next.js Next.js / Nuxt Next.js Django Node + React
Multi-Tenancy ✓ Full RBAC Teams only Teams only
Stripe Billing ✓ Full
White-Label Branding ✓ Full Partial Partial
Admin Dashboard ✓ Full Basic
API Keys Basic
Outgoing Webhooks ✓ 19 events
Credit / Usage System ✓ Dual buckets Basic
Health Monitoring ✓ 8 charts
Product Analytics ✓ 5-tab PM
DataDog Integration ✓ Full
MCP Server (AI Admin) ✓ 26 tools

Comparison based on publicly available information as of March 2026. ShipFast, Supastarter, MakerKit, SaaS Pegasus, and Gravity are trademarks of their respective owners.


Built for AI agents: MCP server, fork-ready architecture, scoped API keys

Software is entering its creator era. The same way YouTube democratized video and Substack democratized publishing, AI agents are democratizing software itself. The person with the idea can now be the person who ships it.

LastSaaS was built entirely through conversation with Claude Code — not as a novelty, but as proof of a new way of working. Every feature, every handler, every component was described in natural language and implemented by an AI agent. The human provided the vision, the architecture, and the design decisions. The agent handled the implementation.

But the real point isn’t that it was built this way — it’s that it’s designed to keep being built this way. LastSaaS is fork-ready for agentic engineering. The codebase follows consistent patterns, uses clear naming, and maintains a structure that AI agents navigate fluently. Fork it, point Claude Code at it, and start describing your product. The agent already understands the patterns — authentication, tenancy, billing, middleware, events — and builds on top of them naturally. You’re not starting from scratch; you’re continuing a conversation.

The built-in MCP server takes this further: once deployed, you can connect Claude directly to your running application and manage it through conversation. Ask about your ARR trend, investigate a spike in error logs, review which API keys are active, or check system health — all in natural language, all read-only by design. It’s the control plane for an AI-native SaaS.


Modern SaaS stack: Go, React 19, TypeScript, MongoDB

Backend: Go 1.25, gorilla/mux, MongoDB
Frontend: React 19, TypeScript, Vite 7, Tailwind 4
Auth: JWT, bcrypt, OAuth, TOTP MFA, Magic Links
Billing: Stripe (Checkout, Portal, Webhooks, Tax)
Email: Resend
Deploy: Docker, Fly.io

Get started — clone, configure, ship

Clone the repo, run the setup script, and you’re live. The README covers everything: quick start, Stripe billing setup, MCP server setup, configuration reference, project structure, deployment guide, and how to extend it for your product.

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