Every startup eventually faces this question: should we use off-the-shelf SaaS tools for this function, or build something custom? The wrong answer costs you money in one of two ways — ongoing subscription cost and workflow friction if you buy something that does not fit, or engineering time and opportunity cost if you build something you should have bought.
Default to Buying (With Conditions)
For most internal tools and non-differentiating functions, SaaS is the right default. Authentication, email delivery, analytics, CRM, payments — these are solved problems. Rebuilding them is almost never a good use of early-stage engineering capacity.
The conditions under which SaaS stops making sense: when the tool does not cover a critical use case, when the unit economics break at your volume, when the tool creates a strategic dependency that becomes a liability, or when the integration complexity equals the build complexity anyway.
Build When It Is Your Competitive Advantage
If a capability is central to what makes your product better than alternatives, building it custom is how you maintain that advantage. Features that live in a third-party tool are features any competitor can have. Custom-built capabilities compound over time — they improve as you learn more about your users, and they are harder for competitors to replicate.
A Decision Framework
- 1Is this a core part of your product's value proposition? If yes, lean toward building.
- 2Does any existing tool solve this well enough at your current scale? If yes, buy and revisit later.
- 3Will building this take more than one engineering sprint? If yes, build only if the answer to question 1 is yes.
- 4What does this cost if you buy for five years? Compare to the engineering cost of building and maintaining.
- 5Does owning this create a competitive moat? If yes, build.
Not sure what to build vs buy?
Asquarify has helped dozens of startups make this decision and execute on it. Talk to us before you commit either way.
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