Practice API DX vocabulary: time to first successful call (TTFSC), API onboarding friction, SDK ergonomics, developer documentation quality, and API DX scoring.
0 / 5 completed
1 / 5
What is 'time to first successful call (TTFSC)' as an API DX metric?
TTFSC is the most important API DX metric: it measures the entire onboarding journey — from discovery through sign-up, credential generation, reading docs, and writing a first call. Short TTFSC (minutes vs. days) strongly correlates with API adoption rates.
2 / 5
A developer says 'the SDK has poor ergonomics.' What do they mean?
SDK ergonomics refers to how natural and intuitive the SDK feels to use in a given programming language. Poor ergonomics means developers fight the SDK rather than focusing on their own logic — leading to adoption abandonment and support tickets.
3 / 5
What is 'API onboarding friction'?
Onboarding friction is the sum of all obstacles a developer encounters before making a successful API call. Even small friction points compound — a confusing sign-up page, a missing code example, or an unhelpful error message can cause developers to abandon the integration.
4 / 5
A team reports 'our API DX score dropped this quarter.' What type of data typically drives this metric?
API DX scores combine quantitative metrics (TTFSC, error rates, support ticket volume) and qualitative signals (developer NPS surveys, feedback forms). A dropping score signals that developer experience is degrading — which predicts reduced adoption and increased churn.
5 / 5
Why is developer documentation quality critical for API monetization?
Documentation is the primary interface between an API and developers who have never used it. Studies consistently show that documentation quality is the top factor in API adoption decisions. Poor docs translate directly to abandonment, negative word-of-mouth, and reduced monetization.