Guides

What is a CWR file?

CWR — Common Works Registration — is the standard file format music publishers use to register musical works with collecting societies: ASCAP, BMI, SESAC, PRS, GEMA, SACEM, SOCAN, the MLC, and dozens more. It is maintained by CISAC, the international confederation of authors’ societies, and the versions in production use today are CWR 2.1 and CWR 2.2.

What's actually in the file

A CWR file is plain text with a .V21 or .V22 extension. Every line is a fixed-width record whose first three characters say what it is:

• HDR/TRL open and close the transmission, with control totals;
• GRH/GRT bracket groups of one transaction type;
• NWR/REV begin a work registration or revision — the work's title, your work number, ISWC, duration;
• SPU/SPT carry each publisher and its collection territories;
• SWR/SWT carry each writer and theirs;
• PWR links a writer to the publisher representing them;
• ALT, PER, REC, ORN and others add alternate titles, performers, recordings, and origins.

Every field sits at an exact character position defined in the CISAC functional specification (CWR19-1070R1 for 2.2). That's the format's strength — a society can machine-process thousands of works — and its trap: one blank mandatory field or a sequence number that skips by one can bounce a whole transaction.

Who sends CWR, and why

Societies accept individual registrations through their portals, but that stops scaling at a few dozen works. CWR is how publishers and administrators register in bulk: one file can carry a whole catalog, and the society answers with an acknowledgement file (ACK) saying, work by work, what was accepted, rejected, or in conflict.

Reading one

You don't need CWR software to see what's in a file: drop it into the free validator and you'll get every work, writer, publisher, and share laid out — plus anything a society would reject, tied to the exact line. If you need to create a file, the generator builds a delivery-ready CWR from a simple form or JSON API.

Check a CWR file free — errors and warnings tied to the exact line, nothing stored: cwrcheck.com.