The build-vs-buy question used to be a 6-month strategic exercise. With AI, you often have to decide in a week — and the wrong call costs you 12 months of momentum. Here's the framework we use with clients.
The 4 questions that decide it
- Is this AI capability core to your competitive moat?
- Does it require sensitive or proprietary data the SaaS can't access?
- Is there a SaaS that already does 80% of what you need?
- Can you absorb 6–12 weeks of build time?
When to buy
- Generic productivity gains (writing, summarizing, transcription)
- Standardized workflows where SaaS captures most of the value
- Speed matters more than differentiation
- Your team lacks AI engineering capacity
Buy-side example
A 50-person services firm wanted AI meeting summaries. We told them: don't build, just buy Fireflies or Otter. Custom build would have been $40k+ and matched 70% of the SaaS feature set.
When to build (or commission a build)
- AI is part of your product's core value proposition
- Your data is too sensitive for third-party SaaS
- You need deep integration into proprietary systems
- Off-the-shelf tools can't match the specificity of your workflow
Build-side example
A medtech client needed AI to analyze proprietary clinical data with HIPAA + audit requirements. No SaaS could touch it. We built a custom RAG system in 8 weeks — now a moat competitors can't match.
The hybrid path (often the best)
Most winning AI strategies are hybrid: buy commodity capabilities (transcription, OCR, embeddings) and build the thin layer that's unique to your business on top.
Common hybrid patterns
- Use OpenAI/Anthropic APIs (buy) + custom RAG over your docs (build)
- Use Twilio + ElevenLabs (buy) + custom voice agent logic (build)
- Use Stripe + Clerk (buy) + AI usage metering and billing (build)
The cost reality
- SaaS AI tools: $20–$500/user/month, fast deploy, capped customization
- Custom AI build: $15k–$200k upfront, $500–$5k/mo run cost, infinite customization
- Hybrid: typically 30–60% of full custom cost with 80%+ of the value
Three traps to avoid
- Building because it's fun — if a SaaS does it well, just buy it
- Buying because it's easy — for core competitive advantage, build
- Skipping the prototype — never commit to either path without a 2-week test