CIP26 Off-Chain Metadata Registry (mainnet)
This is the CIP26 off-chain metadata registry for mainnet. If you intend to register any metadata for on-chain assets that exist on the publicly available testnets only (e.g. preview and preprod environments) please use the metadata-registry from IOHK.
Background
This repository provides a means to register off-chain token metadata that can map to on-chain identifiers (typically hashes representing asset IDs, output locking scripts, or token forging policies).
A server exposes the functionality of a key-value store, allowing users and applications to query registry entries through a RESTful API.
While this registry is limited in scope to handle native tokens only, it will also serve to facilitate a discussion and introduce a standard for a metadata distribution system that is currently put forward as a draft CIP.
Use of this registry is subject to the Registry Terms of Use.
Use of the public API is subject to the API Terms of Use.
Process
New registration
New submissions to this registry will take the form of a GitHub Pull Request with the addition of one JSON file to the mappings/ folder. Submissions will be subject to automated checking for well-formedness and human vetting before being merged to the registry.
Updating existing entries
Modification of entries in this registry require a GitHub Pull Request with the modification of one JSON file in the mappings/ folder. Submissions will be subject to automated checking for well-formedness and human vetting before being merged to the registry.
Semantic content of registry entries
Each entry contains the following information:
| Name | Required/Optional | Description |
|---|---|---|
subject |
Required | The base16-encoded policyId + base16-encoded assetName |
name |
Required | A human-readable name for the subject, suitable for use in an interface |
description |
Required | A human-readable description for the subject, suitable for use in an interface |
policy |
Optional | The base16-encoded CBOR representation of the monetary policy script, used to verify ownership. Optional in the case of Plutus scripts as verification is handled elsewhere. |
ticker |
Optional | A human-readable ticker name for the subject, suitable for use in an interface |
url |
Optional | A HTTPS URL (web page relating to the token) |
logo |
Optional | A PNG image file as a byte string |
decimals |
Optional | how many decimals to the token |
The policy field is optional in order to support Plutus Smart-Contracts which are not linked to a set of signing keys by default. It is used in priority if present. Otherwise, signature verification is performed using user-provided trusted keys.
For a comprehensive description of all fields and how to generate them, please see offchain-metadata-tools.
Submission well-formedness rules
-
Submissions to the registry must consist of a single commit, directly off the master branch of the cardano-token-registry repository.
-
Submissions must add or modify a singular file in the mappings/ folder. Multiple mappings should be split across multiple PRs.
-
The file name must match the encoded
"subject"key of the entry, all lowercase. -
The maximum file size of a single metadata entry is 370KB.
Server
Users and applications can query this registry through an API at https://tokens.cardano.org/metadata.
The API documentation and source code for the server implementation is available with the offchain-metadata-tools.
Use of the https://tokens.cardano.org/metadata API is subject to the API Terms of Use.
Step-by-Step Guide
See Wiki.