# Metadata Standards on Cardano

When tokenizing real-world assets on Cardano, metadata plays a critical role. Metadata gives meaning to a token: what it represents, who backs it, and what information is attached (e.g. audits, legal identifiers, or valuation data).

There are several CIPs used for token metadata:

#### CIP-25 (NFT Metadata Standard)

* Metadata is stored in the minting transaction under label **721**.
* Widely supported by wallets, explorers, and marketplaces.
* Updating metadata requires minting again (minting additional supply or using a **burn + remint** process).
* Works well for simple NFTs or RWAs that do not require frequent metadata changes.

**Example CIP-25 Metadata (JSON):**

```json
{
  "721": {
    "policy_id_here": {
      "WheatToken001": {
        "name": "Tokenized Wheat Certificate",
        "description": "Represents 1 ton of wheat stored at Warehouse #12",
        "image": "ipfs://QmExampleHash",
        "version": "1.0"
      }
    }
  }
}
```

***

#### CIP-68 (Reference NFT with On-Chain Metadata)

* Separates **user tokens** from a **reference NFT**.
* Metadata is stored in the datum of the reference NFT, and user tokens point to it.
* Metadata can be updated by modifying the reference NFT without affecting user-held tokens.
* More complex to implement, but ideal for RWAs that require dynamic data (e.g. audits, price updates, legal status).

**Example CIP-68 Metadata (simplified datum):**

```json
{
  "version": "1.0",
  "name": "Tokenized Wheat Certificate",
  "description": "Represents 1 ton of wheat stored at Warehouse #12",
  "custodian": "Agricola Magdalena SRL",
  "audit_date": "2025-09-01",
  "proof_of_reserve": "ipfs://QmAuditReportHash"
}
```

***

#### CIP-86 (Metadata Updates via Oracles) – <mark style="color:$warning;">Not available yet</mark>

* Allows metadata to be updated without minting or burning tokens.
* Uses a **metadata oracle** assigned to the policy to submit changes.
* Backward compatible with CIP-25.
* Still early-stage, but promising for scenarios where frequent off-chain data must be reflected on-chain.

***

#### Comparison: Metadata Standards on Cardano

| Feature                       | **CIP-25**                                  | **CIP-68**                             | **CIP-86** (in development)          |
| ----------------------------- | ------------------------------------------- | -------------------------------------- | ------------------------------------ |
| **Type**                      | Metadata in minting transaction (label 721) | Metadata stored in reference NFT datum | Metadata managed via assigned oracle |
| **Update method**             | Burn + remint                               | Update reference NFT, user tokens stay | Oracle updates metadata directly     |
| **Complexity**                | Low                                         | Medium–High                            | Medium                               |
| **Wallet / Explorer support** | Very high                                   | Growing                                | Not widely supported yet             |
| **Best for**                  | Static metadata, simple RWAs                | Dynamic RWAs with updates              | RWAs needing frequent off-chain data |
| **Example use case**          | Tokenized certificates                      | Commodities with audits                | Financial assets with live feeds     |