After building 40+ AI integrations and MVPs across SaaS, fintech, healthtech, and marketplaces, we've converged on a default stack.
Most of our builds start with: Next.js + Supabase + Vercel.
This isn't dogma. We deviate when the use case demands it. But this combination handles the majority of what pre-seed and seed-stage founders actually need to build — and it lets us move fast without sacrificing quality.
Here's exactly why we choose it, what each piece does, where it falls short, and when we pick something else.
Table of Contents
- Why Stack Choice Matters More at MVP Stage
- Next.js: Why It's Our Default Frontend Framework
- Supabase: Why We Reach for It Before Anything Else
- Vercel: Why Deployment Shouldn't Be a Decision
- The Full Default Stack We Use
- Where the Stack Falls Short
- When We Use Something Different
- How AI Integration Fits In
- The Honest Tradeoffs
- What This Means for Your MVP
Why Stack Choice Matters More at MVP Stage
At enterprise scale, stack choice is a long-term infrastructure decision with significant migration costs. At MVP stage, it's a speed decision.
The questions that matter at MVP stage are:
- How fast can we go from zero to deployed product?
- How much time are we spending on infrastructure vs. product logic?
- When the MVP gets traction, can it handle the initial growth without a complete rewrite?
The wrong stack at MVP stage costs you weeks. Not because the technology is bad — but because unfamiliar technology, complex configuration, or mismatched abstractions slow down every decision.
Our default stack answers the speed question well. Here's how each piece earns its place.
Next.js: Why It's Our Default Frontend Framework
Next.js is our default for products that need both a public-facing website and an authenticated application — which is almost every SaaS or AI product.
What it handles in one framework:
- Marketing/landing pages (static generation, fast load times, SEO)
- Authenticated app routes (server-side rendering with session context)
- API routes (backend logic without managing a separate server)
- File-based routing that maps naturally to product architecture
Why the App Router changed things
The Next.js App Router (introduced in Next.js 13, stable by 14) made server components the default. This matters for MVPs because server components render data-fetching logic on the server — reducing client-side JavaScript, improving initial load times, and eliminating the waterfall of client-side API calls that makes many React apps feel slow.
For a founder's first product, perceived performance matters. Users judge products harshly if they feel slow on first load.
TypeScript by default
We write all client projects in TypeScript. Not because we're TypeScript evangelists — because on a fast-moving build with multiple developers, type safety catches integration errors before they reach staging. At 15-day velocity, catching bugs early is the difference between shipping on time and missing the deadline.
When we don't use Next.js
When a client needs a mobile app as their primary interface. Next.js is a web framework — for mobile-first products, we evaluate React Native or a web app with a native shell depending on the requirements.
Supabase: Why We Reach for It Before Anything Else
Supabase is what we use when a product needs a database, authentication, and file storage — which is most products.
What you get out of the box:
- Managed PostgreSQL with a sensible schema editor
- Built-in authentication: email/password, magic links, OAuth (Google, GitHub, etc.)
- Row-level security (RLS) — security rules written once in the database
- Realtime subscriptions for live-updating UIs
- File storage with access controls
- Auto-generated REST and GraphQL APIs from your schema
- Edge functions for server-side logic
For an MVP, this means we're writing product logic from Day 1 instead of configuring infrastructure.
The Row-Level Security advantage
RLS is the feature that makes Supabase genuinely different from just "managed Postgres." You write security rules directly in the database — rules like "users can only see rows where user_id matches their authenticated ID." These rules apply at the database level, regardless of how your API is written.
This eliminates a whole category of security bugs that come from forgetting to add auth checks in individual API routes. For a 15-day build, one fewer category of security bugs is significant.
The free tier is genuinely useful
Supabase's free tier supports up to 500MB database, 1GB file storage, and 50,000 monthly active users. For an MVP, this is real headroom. You can validate product-market fit entirely on the free tier.
When we don't use Supabase
When a client has existing infrastructure they need to integrate with (their own Postgres, existing auth system, existing file storage). We don't rip out working infrastructure to standardize on our preferred stack. We work with what's there.
Also for AI-heavy workloads where we need dedicated vector storage — Supabase has pgvector support, but for serious RAG applications we evaluate Pinecone or Weaviate separately.
Vercel: Why Deployment Shouldn't Be a Decision
Vercel is our default deployment platform for Next.js apps. The reason is simple: deployment should not be a decision at MVP stage.
With Vercel + GitHub:
- Every push to main auto-deploys to production
- Every pull request gets a unique preview URL
- SSL is automatic
- CDN and edge network are automatic
- Environment variables are managed in a UI
The alternative — managing your own deployment infrastructure on AWS or GCP from Day 1 — adds days of configuration work that produces no product value.
We move infrastructure to AWS or GCP when a client has specific requirements (compliance, existing infrastructure, cost optimization at scale). For MVP stage, Vercel removes deployment as a variable entirely.
The Full Default Stack We Use
Here's the complete picture of what a typical V12 Labs MVP build looks like:
| Layer | Technology | Why | |---|---|---| | Frontend framework | Next.js 15 (App Router) | Full-stack, SEO-friendly, fast | | Language | TypeScript | Type safety, fewer integration bugs | | Styling | Tailwind CSS | Fast to build, no custom CSS needed | | Database | Supabase (PostgreSQL) | Managed DB + auth + storage + RLS | | Authentication | Supabase Auth | Built-in, supports all common OAuth providers | | File storage | Supabase Storage | Integrated with auth and RLS | | Payments | Stripe or Stripe Checkout | Most reliable, best developer experience | | Email | Resend | Developer-friendly, reliable deliverability | | Deployment | Vercel | Zero-config, preview deploys, fast CDN | | AI/LLM | OpenAI or Anthropic Claude | Depending on use case | | AI orchestration | Direct API calls or LangChain | Direct for simple, LangChain for complex chains | | Vector storage | Supabase pgvector or Pinecone | pgvector for simple RAG, Pinecone for scale | | Background jobs | Vercel Cron or Inngest | For scheduled tasks and async workflows |
Where the Stack Falls Short
Mobile apps Next.js is a web framework. If your core product is a native mobile app, you need React Native or a different stack entirely. A responsive web app wrapped in a WebView is a workaround, not a solution for mobile-first products.
High-performance real-time features Supabase Realtime is good for many use cases, but for products where sub-100ms real-time performance is critical (multiplayer features, live collaboration), dedicated real-time infrastructure (Socket.io, Ably, Liveblocks) performs better.
Complex background processing For products with heavy data pipelines, video processing, or long-running jobs, Vercel's serverless functions have execution time limits. We evaluate dedicated job processing (Inngest, AWS Lambda with longer timeouts, dedicated workers) for these cases.
Very high traffic at launch Supabase free tier has connection limits. If you're expecting immediate high traffic (a successful Product Hunt launch, a viral moment), plan for scaling the database tier before you need it.
When We Use Something Different
Python backend: When AI workloads benefit from Python's ML ecosystem (custom model inference, heavy data processing, LangChain-heavy architectures). We'll build a Python FastAPI backend alongside the Next.js frontend.
AWS instead of Vercel: When clients have compliance requirements (data residency, specific certifications), existing AWS infrastructure, or are at a scale where Vercel pricing becomes a consideration.
PlanetScale or Neon instead of Supabase: For read-heavy workloads where database branching (PlanetScale) or serverless Postgres performance (Neon) is a better fit than Supabase.
React Native: For products where a native mobile app is the primary interface and a web app is secondary.
How AI Integration Fits In
Our AI stack layers on top of the core framework:
For LLM integration:
- OpenAI GPT-4o for most tasks — broad capability, good API reliability
- Anthropic Claude 3.5 Sonnet for document processing (long context window), analysis, and tasks requiring nuanced reasoning
- Direct API calls for simple integrations (one model, one task)
- LangChain or LlamaIndex for complex chains (multiple models, RAG, tool use, memory)
For vector storage/RAG:
- Supabase pgvector for simple semantic search (under 100k vectors, single collection)
- Pinecone for serious RAG applications (multiple namespaces, scale, metadata filtering)
For voice AI:
- Deepgram for speech-to-text (low latency, good accuracy on domain-specific vocabulary)
- ElevenLabs or OpenAI TTS for text-to-speech
- Custom orchestration layer for full voice agent workflows
For document processing:
- LlamaParse or custom extraction for structured data from PDFs
- Claude API for long-document analysis (200k token context window)
The Honest Tradeoffs
What the stack trades for speed:
Vendor dependency. Supabase, Vercel, and Stripe are third-party services. If any of them has an outage, your product is affected. For MVP stage, this is an acceptable tradeoff — the alternative (running your own infrastructure) creates more operational risk, not less.
Not always the cheapest at scale. Vercel and Supabase have pricing that scales with usage. At high scale, running your own infrastructure on AWS may be cheaper. This is a good problem to have — it means your product worked.
Opinionated architecture. Next.js App Router is opinionated. If a developer joining your team has strong opinions about a different framework, there's friction. For most early-stage teams, having an opinionated architecture is a feature, not a bug.
What the stack gets right:
Developer experience is excellent. Documentation is mature. Community support is strong. Deployment is automated. Security defaults are good. Time from zero to deployed product is measured in hours, not days.
What This Means for Your MVP
You don't need to care deeply about stack choices to build a successful product. But you do need a team that's made these choices thoughtfully and knows how to execute on them.
The questions to ask any agency or developer about their stack:
- What do you use by default and why?
- When do you deviate from that default?
- What does deployment and infrastructure look like from Day 1?
- Who owns the infrastructure accounts and credentials at launch?
The answers tell you whether they've built enough products to have opinions — and whether those opinions are based on experience or convention.