SaaSpark Clerk
Drop-in authentication and user management for modern apps.
- Category: auth-identity
Why this tool
Drop-in auth that handles MFA, orgs and SSO without bespoke flows.
Supabase
MCPOpen-source Firebase alternative with Postgres, auth, storage.
- Category: database-baas
Why this tool
Postgres-backed BaaS with EU regions; you'll outgrow the BaaS layer later but Postgres stays.
Vercel
Frontend hosting and serverless platform built for Next.js.
- Category: hosting-deployment
Why this tool
Next.js on Vercel is the friction-less default; switch to Firebase App Hosting if you outgrow it.
Resend
Email API for developers. Send transactional and marketing email at scale.
- Category: transactional-email
Why this tool
Developer-first API, generous free tier, EU delivery.
Loops
Marketing email built for modern SaaS — automations, broadcasts.
- Category: marketing-email
Why this tool
Lifecycle automations and broadcasts without leaving the SaaS toolkit.
Stripe
Payments infrastructure for the internet.
- Category: payments-billing
Why this tool
The default for SaaS billing; pair with Stripe Tax for EU VAT.
Stripe Tax
Automated sales tax, VAT and GST calculation for Stripe Billing.
- Category: tax-compliance
Why this tool
Automated VAT collection — required for selling to EU consumers and businesses.
Plausible
Lightweight, GDPR-friendly web analytics — no cookies, no banners.
- Category: product-analytics
Why this tool
GDPR-compliant page analytics without cookie banners (alternative to PostHog when privacy is the priority).
PostHog
Open-source product analytics, session replay, feature flags.
- Category: product-analytics
Why this tool
Events, funnels, session replay and feature flags in one tool.
Crisp
Live chat widget, knowledge base and shared inbox.
- Category: live-chat
Why this tool
Free tier covers chat + shared inbox; EU-friendly hosting.
Linear
MCPIssue tracking built for product teams that ship fast.
- Category: project-mgmt
Why this tool
Fast issue tracker that scales with the product team.
Cal.com
Open-source scheduling for individuals and teams.
- Category: scheduling-booking
Why this tool
Self-hosted-able scheduling that respects your data — open-source.
When to use this stack
You're building a B2B SaaS that needs to invoice EU customers, respect GDPR by default, and grow on a freemium acquisition motion.
What to substitute
- Clerk → Firebase Auth if you're already on Firebase.
- Vercel → Firebase App Hosting if you want a single billing surface with Firestore.
- Loops → Customer.io if you outgrow Loops' segmentation.