Overview
The CRFA Offchain Data Registry is a free, public lookup list that tells you which app a smart contract, one of the programs that run DApps, belongs to. On the blockchain, smart contracts show up only as long codes called script hashes, a kind of fingerprint for each program. The registry pairs those fingerprints with the DApps that use them1, so a tracking site can show a project name instead of a raw code.
The CRFA Offchain Data Registry covers DApps on Cardano. It is maintained by Cardano Fans (CRFA), a team that runs a Cardano stake pool and publishes open-source developer tools2. Cardano Fans lists it as the data source behind DappsOnCardano, a site that tracks DApp activity2. The repository is open source under the MIT License3.
Key Features
- Project names for contract fingerprints. Each DApp gets its own file listing its name, website, category, and the script hashes of its smart contracts, grouped by release such as V1 or V21,4,5.
- History that survives upgrades. A project's file can keep older contract versions next to newer ones, so activity from a retired version still traces back to the right DApp. The Minswap entry, for example, starts with its pre-launch load tests4.
- Audit and source-code links per release. An entry can name the firm that audited a release, link the audit report, and record whether the contract code is open source, with a link to that code5.
- One consistent format, checked automatically. A shared rulebook, called a JSON schema, defines which fields and values an entry may use5. An automated check runs on each proposed change to the DApp files and rejects any file that breaks those rules6.
- Meaning for transaction notes. A separate metadata folder explains numbered labels that can be attached to a transaction. Label 674, for example, marks the message or comment field defined in CIP-20, a Cardano improvement proposal7.
What to Expect
Visiting the CRFA Offchain Data Registry means landing on a GitHub repository, not an app. You browse a folder of files, one per DApp and named after the project, and open any file to read its details as plain structured text1.
For everyday Cardano users, the registry works behind the scenes. Its value shows up on sites built on it, such as DappsOnCardano, which Cardano Fans lists as running on the registry's data2. You may never open the registry yourself, but sites that use it can show a project name where the blockchain only has a code.
Developers and analysts can download the files for their own dashboards or research. DApp teams are invited to add their project or fix mistakes through a pull request, which is a GitHub request to change the files, and the maintainers describe their upkeep as best effort1.
The README, the repository's front-page guide, also explains why entries need updating over time. On Cardano, nothing forces a project to keep a single script hash, so a project can change its fingerprints over time by building new data into its contracts1. A project's file is the place where those changes get recorded.
