Drumlin Labs builds and operates its tools with heavy automation. Every tool's output is verifiable regardless of how it was built — that's the point of the receipts.
Every tool reports the inputs it read and the units it billed. A verdict can be re-derived from the same public sources we used, and an invoice can be reconciled line by line against what was actually delivered — duplicates, empty results and failed lookups are not billed, and the run says so in its own output.
The point is narrow and worth stating plainly: you should not have to trust us to know whether a result is right or a charge is fair.
SPF, DKIM and DMARC for a list of domains, with the exact records each verdict was computed from: the full DMARC tree walk, the SPF lookup count, and which DKIM selectors answered.
Emails and phone numbers from the URLs you supply, priced per contact delivered. The run reports what it did with every URL you sent: fetched, refused, failed or duplicate — and the receipt reconciles what was delivered against what was billed.
Wrong results, questions about a charge, or anything else: support@drumlin.dev — monitored, best-effort. Charges, invoices and refunds for tools sold on the Apify Store are handled by Apify as merchant of record.