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.
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.