02

Buy: Rent a product someone else builds and runs

You adopt a SaaS, vendor platform or managed service. Someone else spreads the R&D across thousands of customers and handles upgrades, uptime and compliance for you.
Pros & cons
+Fastest to production
● same

Sign a contract, configure, integrate. Days, not quarters.

✦Still fast. AI mostly speeds up the integration work on your side.

+Shared R&D cost
▼ weaker

Thousands of customers fund the edge cases, so you get years of hardening for a subscription.

✦When building gets cheaper, the discount you get from shared R&D gets smaller, especially for thin CRUD tools.

+Battle-tested & certified
▲ stronger

SOC 2, PCI, ISO and uptime SLAs come in the box. Someone else is on-call.

✦AI can write code quickly. It can't write trust, certifications or audit history.

+Zero maintenance
● same

The vendor handles upgrades, security patches and scaling. Your team stays on your product.

✦Still true, but AI shrinks the maintenance cost of the Build alternative, so the gap narrows.

+Network effects & data
▲ stronger

Some products are valuable because of their network or dataset, like fraud signals or bank connectivity.

✦Proprietary networks and data can't be generated. These vendors get more defensible.

−Lock-in & switching cost
▼ weaker

Data, workflows and integrations pile up. Leaving becomes a project in itself.

✦Agents write migration scripts and adapters, so leaving is cheaper than it used to be. It's still not free.

−Pricing scales against you
● same

Per-seat and per-transaction pricing grows linearly while your costs to build would stay flat.

✦Unchanged, and more visible now that Build is cheaper to compare against.

−80% fit
▼ weaker

You bend your process to the tool. The last 20% is workarounds, spreadsheets and glue.

✦Vendors ship AI configurability, and your glue code gets cheaper to write.

−No differentiation
▲ stronger

Your competitors can buy the exact same thing tomorrow.

✦When everyone buys the same AI-enabled SaaS, it stops being an advantage for anyone.

−Vendor risk
▲ stronger

Price hikes, acquisitions, shutdowns, roadmap changes. Your fate is tied to theirs.

✦Many AI-era vendors are young, and incumbents are being disrupted. Vendor churn is higher.

green = AI helps this optionred = AI hurts this option▲▼ = the point itself gets stronger / weaker
Score profile
Time to market5
Low upfront cost4
Low cost at scale2
Fit & control2 → 3
Differentiation1
Reliability & determinism4
Low maintenance burden5
Low lock-in2 → 3
Handles messy input2 → 4
Compliance & audit5
Grey = pre-AI (2022). Colour = AI era (2026). 5 = best.
Reach for Buy when
  • →It is commodity: every company needs it, none wins with it
  • →Trust, certification or a network is the product
  • →You need it this week
  • →Usage is small enough that fees stay trivial
Examples: Auth, email, observability · CRM, HR, accounting · KYC providers, card processors
  • why it mattersLook at how pricing scales. A $20 seat looks cheap at 10 people and costs more than an engineer at 1,000.
  • why it mattersAsk what the vendor's moat is. If it's the UI, a coding agent can rebuild it. If it's licenses, data or network, keep paying them.
  • why it mattersBuy the boring layer and own the integration layer. Your glue code is where process fit lives, and it's cheap to write now.