Startups Oct 8, 2025 8 min read

From MVP to 100K Users: The Technical Journey of a Funded Startup

A Fixl grant recipient shares their technical journey — the architecture pivots, scaling challenges, and engineering decisions that enabled growth.

AR

Alex Rivera

Engineering Lead

The Beginning

NovaTech was one of the first recipients of the Fixl Startup Grant in 2024. They had a compelling idea: an AI-powered project management tool for remote teams. What they didn't have was the engineering capacity to build it. The grant provided them with a senior architect and two full-stack engineers for 4 months.

This is their technical journey from idea to 100,000 active users in 14 months.

MVP Phase (0-1K Users)

The first 8 weeks focused on a ruthlessly scoped MVP:

  • Stack: Next.js + Supabase (PostgreSQL + Auth + Real-time)
  • Scope: Three features only — task boards, team chat, and AI task suggestions
  • Architecture: Monolith deployed on Vercel, Supabase for everything else
  • Cost: $0/month on free tiers

Key decisions that paid off:

  • Choosing Supabase gave them auth, database, real-time subscriptions, and storage in one platform
  • Using Next.js App Router meant they could add pages without restructuring
  • Deploying to Vercel eliminated DevOps overhead entirely

The MVP launched 6 weeks after the grant started. First 200 users came from the founders' Twitter following.

Finding Product-Market Fit

Months 3-6 were about iteration:

  • User interviews: Weekly calls with power users. The AI suggestions feature was underused — users wanted AI for meeting notes instead
  • Pivot: Dropped AI task suggestions, built AI meeting summarization. Usage doubled in two weeks
  • Metrics: Tracked daily active users, task completion rates, and session duration
  • Retention: Day 7 retention improved from 15% to 42% after the pivot

Technical debt accumulated during this phase, but it was the right call. Speed of iteration mattered more than code quality.

Scaling Phase (10K-100K)

Growth brought technical challenges:

  • Database performance: Supabase PostgreSQL hit connection limits. Migrated to connection pooling via PgBouncer
  • Real-time at scale: WebSocket connections exceeded Supabase limits. Added a dedicated real-time server using Socket.IO + Redis
  • Search: PostgreSQL full-text search couldn't keep up. Added Meilisearch for instant search across projects and tasks
  • Background jobs: Meeting transcription and AI processing moved to a queue system (BullMQ + Redis)
  • CDN: Static assets and user uploads moved to Cloudflare R2 + CDN

Monthly infrastructure cost went from $0 to $2,800 — still remarkably lean for 100K users.

Architecture Evolution

The architecture evolved through three phases:

Phase 1 (MVP): Monolith on Vercel + Supabase. Simple, fast, free.

Phase 2 (Growth): Same monolith + dedicated real-time server + Redis + background job processor. Added complexity only where needed.

Phase 3 (Scale): Extracted meeting AI processing into a separate service (Python, deployed on Railway). Everything else stayed monolithic.

The key insight: they resisted the urge to "properly architect" the system until performance data told them exactly where to invest.

Advice for Founders

  1. Choose boring technology: Next.js + PostgreSQL is boring. It's also incredibly productive and well-documented
  2. Measure before you optimize: Don't pre-optimize. Wait until you see actual bottlenecks in production
  3. Extract services only when you must: NovaTech has exactly one microservice — the AI processor — because it has fundamentally different compute requirements
  4. Invest in monitoring early: They added PostHog (analytics), Sentry (errors), and BetterStack (uptime) in month 2. These tools paid for themselves many times over
  5. Automate deployments from day one: Every merge to main deploys automatically. No "deployment days"
  6. Talk to users constantly: The best technical decisions came from understanding user needs, not from reading tech blogs

NovaTech is now a 15-person company with $2M ARR. The grant gave them the engineering runway to find product-market fit before raising their seed round.

Tags
StartupsMVPScalingGrowth
AR

Written by

Alex Rivera

Engineering Lead

Part of the Fixl engineering team, sharing insights from building production-grade software for startups and enterprises.

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