PLC is a persistent global identifier system, which allows accounts to retain relationships while changing names or migrating between service providers. It uses cryptography to gives individuals (or organizations) direct control and ownership over their identitifier. It does not make use of any blockchain or cryptocurrency technology, and is inexpensive enough to provide as a no-cost service.
PLC stands for "Public Ledger of Credentials". The system implements the W3C Decentralized Identifier (DID) standard. This makes it interoperable and reusable by other applications and organizations.
The DID PLC system was originally developed in 2022 by Bluesky Social PBC to support AT Protocol (atproto). They wanted a strongly consistent, highly available, recoverable, and cryptographically secure method with fast and cheap propagation of updates. Since then over 40 million atproto account identifiers have been registered.
In 2026 the PLC Organization was founded to be a neutral steward for the DID PLC system. The system may evolve to add functionality or improve security, but will do so in a backwards-compatible manner so that existing DIDs will continue to resolve.
DID resolution can be as simple as:
curl -s "https://plc.directory/did:plc:ewvi7nxzyoun6zhxrhs64oiz" | jq .Jump in to the specification to understand how to verify self-certifying operation logs.
Check out the HTTP API documentation (generated from an OpenAPI schema) for details on how to submit operations, fetch the current DID document, or get a paginated export of all operations for all accounts.