First paying customer came from fixing a real bug fast

Sled is an affiliate tracking tool for founders who use Polar.sh. The first paying customer started on the free plan, set up a webhook, ran a test, and saw nothing appear. Instead of leaving quietly, the customer sent a detailed bug report with the raw data attached. The deeper issue was not only the code; the product gave the customer no way to see what happened to the webhook. The customer could not tell whether their setup was wrong or the service was broken, while only the operator could check Vercel function logs. A webhook dashboard tab was shipped the same day, with a new database table, color-coded statuses, and plain error tips. A few hours later, the customer tested again, and the new screen exposed a real bug: Polar’s tool returned webhook data in one naming style, while Sled read it in another. That quiet failure would likely have affected every future Polar customer, so it was fixed quickly, and the customer came back and paid.