CIP26 Off-Chain Metadata Registry (testnets)

This is the CIP26 off-chain metadata registry for all publicly available testnets. If you intend to register any metadata for on-chain assets that exist on the cardano mainnet, please use the cardano-token-registry from CF.

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.

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 registry/ 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 registry/ 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

1. Submissions to the registry must consist of a single commit, directly off the master branch of the metadata-registry-testnet repository.

2. Submissions must add or modify a singular file in the registry/ folder. Multiple mappings should be split across multiple PRs.

3. The file name must match the encoded "subject" key of the entry, all lowercase.

4. The maximum file size of a single metadata entry is 370KB.

Server

Users and applications can query this registry through an API at https://metadata.cardano-testnet.iohkdev.io/metadata.

The API documentation and source code for the server implementation is available with the offchain-metadata-tools.

Step-by-Step Guide

See Wiki.