Northwall moves money across 142 currencies through a single composable API. The product was genuinely good. The funnel was not: almost every new customer arrived through a sales call, and the CTO was the bottleneck on a pipeline the company wanted to double.
The metric nobody was watching
We instrumented the path from landing page to first successful API call. The median was just over six days. Not because integration was hard — the SDK was clean — but because nothing on the site let an engineer confirm the platform did what they needed without booking a meeting first.
Developers were evaluating Northwall the way buyers evaluate enterprise software, because the site was built for buyers. The people making the decision were engineers, and engineers evaluate by trying.
Designing for the person who reads code, not decks
We rebuilt around one job: get a competent engineer to a working call as fast as possible. Real request and response payloads on the homepage. Quickstart templates for Node, Python, Go and Ruby one click from the hero. Per-transaction pricing published rather than gated behind "talk to sales".
The live treasury view in the hero is not a screenshot. It renders the same components the product does, from sample data, which meant marketing stopped drifting away from the product every release.
If an engineer cannot try it in ten minutes, your competitor is the one who let them.
The design system was the delivery mechanism
We shipped 48 components in a documented library wired straight into their Next.js codebase. Marketing pages and product surfaces now share primitives, so a change to a button happens once. Time from design handoff to merged PR dropped from nine days to three.
Where it landed
Developer activation rose 3.1x. Median time to first API call fell from six days to eleven minutes. Self-serve signups rose 47% while sales-assisted onboarding dropped 38% — the same growth, with the founding team out of the critical path.