MVP Feature Selection: What to Build vs What to Buy as a Solo Founder

TL;DR: The single most important decision for a solo founder building a SaaS MVP is what to build from scratch and what to buy. Build the wrong thing, and you waste weeks. Buy the wrong thing, and you lock yourself into someone else's roadmap. This article presents a decision framework — a four-quadrant analysis for every feature, a prioritization matrix, and specific recommendations for the most common SaaS features.

The Cost of Building the Wrong Thing

Every feature you build from scratch costs:

• Proposal phase: 5-10 hours (planning, spec, design)
• Build phase: 20-80 hours (coding, testing, debugging)
• Maintenance phase: 5-10 hours/month (updates, bug fixes, support)
• Opportunity cost: Whatever else you could have built instead

For a solo founder with a 12-week runway before launch, building the wrong feature can cost 2-4 weeks of development time — potentially the difference between shipping and stalling.

The Decision Framework

Four-Quadrant Analysis

Strategic: Features that define your product's unique value proposition. Non-Strategic: Features users expect but do not differentiate on. High Complexity: Requires significant engineering effort to build correctly. Low Complexity: Simple to implement with standard patterns.

MVP Feature Assessment Table

Apply this framework to common SaaS features:

Build vs Buy Decision Matrix

For each feature, score:

In this example, the scores are equal — meaning you could go either way. Use this framework to make objective decisions instead of gut feelings.

The Template Advantage

A high-quality SaaS template like TanStack Ship compresses the decision tree significantly:

// src/lib/auth-client.ts — already included
import { createAuthClient } from "better-auth"

// src/lib/billing-db.ts — already included
import { createSubscription, cancelSubscription } from "../lib/billing-db"

// src/server/campaign-db.ts — marketing features included
import { createCampaign, trackClick } from "../server/campaign-db"

// src/server/credit-db.ts — loyalty system included
import { grantCredits, deductCredits } from "../server/credit-db"

A template converts these decisions from "Build vs Buy" to "Use vs Customize":

Practical Prioritization: The RICE Framework

Combine the build-vs-buy analysis with RICE prioritization:

RICE = (Reach × Impact × Confidence) / Effort

The higher the RICE score, the sooner you should build (or buy) the feature.

What I Wish I Knew

These lessons come from shipping the MVP of tanstackship.com:

Things I Regret Building

• Custom admin panel — Should have bought a template
• Email template system — Should have used a third-party service
• Custom analytics dashboard — Should have shipped with PostHog first

Things I Regret Buying (at MVP stage)

• Premium animation library — CSS transitions were sufficient
• Expensive analytics platform — Started with free tier, upgraded later
• Dedicated image processing service — Workers-based pipeline was enough

The 80/20 Rule for SaaS Features

80% of your users only care about 20% of your features. Identify those 20%:

const features = {
  mustHave: [
    "User authentication",
    "Core business logic",
    "Pricing and payment",
    "Basic CRUD operations",
  ],
  niceToHave: [
    "Advanced filtering",
    "Export to CSV/PDF",
    "Webhook integrations",
    "Role-based permissions",
  ],
  later: [
    "API for third parties",
    "SSO / SAML",
    "White-labeling",
    "Custom reports",
  ],
}

Decision Flowchart

Is this feature core to your product's value?
├── YES → Build it (invest resources)
└── NO → Is it complex?
    ├── YES → Buy or use a template
    └── NO → Can you launch without it?
        ├── YES → Skip it for now
        └── NO → Build a quick version (1-2 days max)

Conclusion

The build-vs-buy decision is the single highest-leverage decision a solo founder makes. Every hour spent evaluating this trade-off saves 10 hours of unnecessary development.

The key insight: build what differentiates you, buy everything else. Your authentication flow will not be the reason users choose your product. Your core business logic — the algorithm, the workflow, the data visualization — that is where your competitive advantage lives.

To support your feature decisions with the right infrastructure, explore our SaaS Database Architecture guide for data layer design, the Finding Product-Market Fit framework for validating your choices, and the Choose Your SaaS Tech Stack 2026 guide for technology decisions. For a complete acceleration path from idea to launch, see the Zero to MVP in 4 Weeks guide.