Blackbox Checker

Blackbox Checker is a free tool from Doubly that helps musicians and songwriters discover how much of their catalog is sitting unclaimed at The Mechanical Licensing Collective. When streaming services pay mechanical royalties but the MLC cannot match a recording to its registered work, or when shares of a work have not been claimed by anyone, the money still arrives. It just never leaves. That pool of unmatched and unclaimed funds is the black box, and it holds hundreds of millions of dollars that should be reaching creators. Blackbox Checker tells you whether any of it belongs to you.

The tool works by reading every album and single credited to a Spotify artist profile and cross referencing each recording against the MLC's weekly bulk database using ISRC codes. It intentionally skips compilations and features to focus on your core catalog. You can search by pasting a Spotify artist link, entering an artist ID, or typing a name. Within seconds it categorizes your recordings into five distinct buckets based on their registration and matching status. Recordings marked as Looks Good are fully linked with every ownership share claimed and royalties flowing correctly to their rightful owners. Those labeled Needs Matching have a registered work but lack service specific recording matches, which means separate copies on each streaming platform are not all connected to the underlying composition. Missing Shares means the work is partially claimed but some ownership percentage has not been registered by anyone. Fully Unclaimed indicates a linked work where no shares have been claimed at all, meaning the entire song is generating royalties that are going nowhere. Missing Work is the worst case, where the recording exists in MLC data but the underlying composition is not even registered at all. There is also a Not in MLC Data status for recordings that simply do not appear in the database yet, often because of recent releases, ISRC assignment delays, or uploads that happened after the most recent weekly data snapshot.

Beyond categorization, the tool estimates the dollar value at risk for your catalog. It pulls Spotify stream counts, extrapolates across other streaming services using market data, calculates the US market portion of those streams, and applies the actual mechanical royalty rate measured from real MLC distributions. The result is a range rather than a precise invoice, with a margin of roughly thirty five percent in either direction. When the MLC's own internal estimates exceed this calculation, the tool defaults to their higher figure to give you the more conservative assessment. You can exclude covers and tracks you do not own from the calculation so the numbers reflect your actual exposure rather than inflating the total with songs you have no claim to. One example from the site describes a catalog song with forty eight unmatched copies across thirteen streaming services, worth over a thousand dollars in accumulated royalties, sitting behind a perfectly registered work that simply was not linked correctly. The money was there the whole time. It just could not find its way to the songwriter.

The problem Blackbox Checker addresses is widespread and hits independent artists hardest. The MLC holds an enormous pool of unmatched royalties that grows larger every month as streaming continues to dominate music consumption. Most small creators do not have a publisher handling registrations on their behalf, and distributors often do not complete the mechanical licensing step even when they handle other aspects of release. Many independent musicians do not even know the black box exists, let alone that their money might be stuck in it. Blackbox Checker surfaces that information without requiring a login or payment, lowering the barrier to discovering the issue before any unclaimed funds expire, get distributed proportionally to other rights holders, or otherwise disappear from reach.

It is worth understanding the limits of what this tool can and cannot do. It covers only mechanical royalties collected by the MLC in the United States. It does not touch performance royalties handled by PROs like ASCAP, BMI, or SESAC. It does not address sync licensing fees from TV, film, or advertising placements. It does not cover international collections through societies outside the US, and it has nothing to do with master recording ownership or the royalties that flow to labels and distributors. If one recording is affiliated with multiple works in the MLC database, the tool selects the best match based on title similarity and ISWC presence, but edge cases involving samples, interpolations, or disputed ownership may need manual verification. If you find unclaimed money here, the next step is registering your works and claiming your shares directly with the MLC, which is a separate process the tool does not automate.

Access is completely free with no signup required. You paste a Spotify link, run the check, and see your results immediately in the browser. Doubly, the company behind it, offers catalog wide audits for labels, publishers, and distributors as a separate paid service, but the Blackbox Checker itself is a standalone utility that costs nothing to use. For any songwriter, producer, or independent artist curious whether streaming royalties are actually reaching them, this is the fastest and cheapest way to find out what is missing and how much it might be worth before the money slips away for good.