> ## Documentation Index > Fetch the complete documentation index at: https://nexus.gerowallet.io/docs/llms.txt > Use this file to discover all available pages before exploring further. # Get the metadata of many native assets in one call > Resolve the metadata of up to 100 assets in one call. Every requested unit is a key of the response's data object, in request order and in your own spelling; a unit that is unknown or has none of the three kinds of metadata maps to null rather than being dropped, so the response can be read against the request without re-deriving it. onchainMetadata is only the asset's own CIP-25 entry from label 721 of its minting transaction, not the whole label-721 body, and it is an object. This differs from detailedInfo's onchainMetadata, which is the whole minting-transaction metadata as JSON text. cip68Metadata is the CIP-68 reference datum's metadata map decoded to JSON: byte strings become UTF-8 text where they are valid UTF-8, otherwise they stay hex, and chunked lists stay arrays. cip68Version is the datum's version field. metadata is the token-registry entry, the same object detailedInfo returns as metadata. Served by one Koios asset_info call, because yaci-store indexes no asset metadata. Works on mainnet, preprod and preview. ## OpenAPI ````yaml https://nexus.gerowallet.io/v3/api-docs post /api/assets/metadata openapi: 3.1.0 info: title: Nexus API description: >- Multi-chain blockchain data API for Cardano (and Apex), Bitcoin, and Midnight. ## Blockchains & Networks Endpoints are grouped by **blockchain**. Pick the target **network** with the `network` query parameter. A network is an environment *within* a blockchain, not a separate endpoint family. - **Cardano & Apex**: one shared set of UTxO endpoints serves `CARDANO_MAINNET`, `CARDANO_PREPROD`, `CARDANO_PREVIEW`, `APEX_PRIME_MAINNET`, `APEX_VECTOR_MAINNET`, `APEX_VECTOR_TESTNET` - **Bitcoin**: `BITCOIN_MAINNET`, `BITCOIN_TESTNET4` - **Midnight**: `MIDNIGHT_MAINNET`, `MIDNIGHT_PREPROD`, `MIDNIGHT_STAGENET` These are the values published on each operation's `network` schema, and what generated clients send. A kebab-case alias (`cardano-mainnet`) is also accepted, and matching is case-insensitive — see the note on the parameter itself. ### Key scope: one chain, one network Each API key is scoped to **one chain and one network**, fixed at creation time. A `CARDANO_MAINNET` key cannot query `CARDANO_PREPROD`, and it cannot query Bitcoin or Midnight at all. Create one key per chain and network under the same account. Sending a `network` value that does not match the key returns **400 Network Mismatch**; omit the parameter and the request runs against the key's own network. What is uniform across chains is the integration surface, not the credential: one account, one base URL, one auth header, one docs site. ## Authentication Send your API key in the `X-Api-Key` header. This is the credential for programmatic access (create one in the dashboard; keys start with `nxs_`). `Authorization: Bearer ` is only for JWT **session** tokens issued by `/api/auth/login` (browser/mobile apps), not for API keys. ## Add-ons Capability is gated separately from network scope. Market data, wallet analytics, transaction building, MCP, and IPFS are paid add-ons; those endpoints return **402 Payment Required** on a key whose plan does not carry the matching add-on, even when the chain and network match. contact: name: Nexus Team url: https://nexus.gerowallet.io/support email: nexus@gerowallet.io license: name: Apache 2.0 url: https://www.apache.org/licenses/LICENSE-2.0.html version: 1.0.0 servers: - url: https://nexus.gerowallet.io description: API Server security: - apiKeyAuth: [] - bearerAuth: [] tags: - name: Cardano · Blocks description: Cardano Block API - name: Cardano · Policy description: Cardano Policy API - name: IPFS description: IPFS Content Resolution API - name: Bitcoin · Ordinals description: Ordinals + runes metadata (ord indexer) - name: Partner description: Aggregator revenue share for partner key holders - name: Cardano · Metadata description: Label-scoped transaction metadata API - name: Cardano · Assets description: Token Registry Metadata - name: Cardano · Transactions description: Cardano Transactions API - name: Midnight · Transactions description: Midnight-specific transaction endpoints (unshielded UTXOs) - name: Bitcoin · Mempool description: Bitcoin mempool snapshot - name: Midnight · DUST description: DUST registration + generation status - name: Cardano · Stake Pools description: >- Cardano stake pool information including registrations, retirements, and pool metadata - name: Cardano · Network description: Cardano Network API - Query static network / genesis parameters - name: Cardano · RealFi description: >- RealFi Earn (USDr / sUSDr) read API. Wallet-keyed reads take a bech32 address; Nexus derives the key hashes RealFi matches on. Networks without a RealFi deployment answer 502 rather than guessing. - name: Cardano · Addresses description: Cardano Address API - name: Bitcoin · Addresses description: >- Bitcoin address-keyed queries: stats / balance / UTxOs via electrs; ordinals via ord - name: Bitcoin · Transactions description: Bitcoin transaction lookup and submission - name: Cardano · Governance description: >- Cardano on-chain governance: DReps, governance actions + votes, constitutional committee, constitution - name: Cardano · DReps description: >- Cardano delegate representatives (DReps): voting power, status, metadata, delegators - name: Cardano · Transaction Builder description: >- Cardano transaction building API. Builds unsigned transactions server-side for client-side signing and submission. Network can be specified in the request body or as a query parameter. Body takes precedence over query parameter. - name: Cardano · Assets description: Cardano Asset API - name: Cardano · Accounts description: Cardano Account API - name: Bitcoin · Fees description: Bitcoin fee-rate estimates by confirmation block target - name: Bitcoin · Blocks description: Bitcoin block lookup - name: Cardano · Handles description: ADA Handle resolution - name: Cardano Market Data description: Endpoints from cardano-market-data - name: Midnight · Indexer description: Transparent proxy to the Midnight GraphQL indexer - name: Cardano · Scripts description: Cardano script & datum API - name: Cardano · Epochs description: Cardano Epoch API - Query protocol parameters and epoch information - name: Bitcoin · Chain description: Bitcoin chain-tip and sync state paths: /api/assets/metadata: post: tags: - Cardano · Assets summary: Get the metadata of many native assets in one call description: >- Resolve the metadata of up to 100 assets in one call. Every requested unit is a key of the response's data object, in request order and in your own spelling; a unit that is unknown or has none of the three kinds of metadata maps to null rather than being dropped, so the response can be read against the request without re-deriving it. onchainMetadata is only the asset's own CIP-25 entry from label 721 of its minting transaction, not the whole label-721 body, and it is an object. This differs from detailedInfo's onchainMetadata, which is the whole minting-transaction metadata as JSON text. cip68Metadata is the CIP-68 reference datum's metadata map decoded to JSON: byte strings become UTF-8 text where they are valid UTF-8, otherwise they stay hex, and chunked lists stay arrays. cip68Version is the datum's version field. metadata is the token-registry entry, the same object detailedInfo returns as metadata. Served by one Koios asset_info call, because yaci-store indexes no asset metadata. Works on mainnet, preprod and preview. operationId: getAssetsMetadata parameters: - name: network in: query required: false schema: type: string description: >- Accepts either the value listed here (`CARDANO_MAINNET`) or its kebab-case alias (`cardano-mainnet`); matching is case-insensitive. Omit it and the network is taken from the API key. A value that disagrees with the key's own network returns 400 Network Mismatch. enum: - CARDANO_MAINNET - CARDANO_PREPROD - CARDANO_PREVIEW - APEX_PRIME_MAINNET - APEX_VECTOR_MAINNET - APEX_VECTOR_TESTNET - MIDNIGHT_MAINNET - MIDNIGHT_PREPROD - MIDNIGHT_STAGENET - BITCOIN_MAINNET - BITCOIN_TESTNET4 requestBody: content: application/json: schema: $ref: '#/components/schemas/BulkAssetMetadataRequest' required: true responses: '200': description: Metadata resolved content: application/json: schema: $ref: '#/components/schemas/BulkAssetMetadataResponseDto' additionalProperties: default: '' default: '' '400': description: Empty list, more than 100 units, or a malformed unit content: application/json: schema: type: string additionalProperties: default: '' default: '' example: error: At most 100 units per call '501': description: No provider on the network implements the batch metadata read content: application/json: schema: type: string additionalProperties: default: '' default: '' example: error: Operation Not Supported '503': description: Chain-data providers unavailable content: application/json: schema: type: string additionalProperties: default: '' default: '' example: error: Service Unavailable components: schemas: BulkAssetMetadataRequest: type: object default: null description: Bulk asset metadata request properties: units: type: array default: '' description: >- Asset units (56-hex policy id followed by the asset-name hex), max 100 per call example: - >- 9a2ec5c92daccbb269611a9eae7a40f9788d3f9c0229661b6234286f000de1406f766f3532 items: type: string pattern: ^[a-fA-F0-9]{56}(?:[a-fA-F0-9]{2}){0,32}$ maxItems: 100 minItems: 0 required: - units BulkAssetMetadataResponseDto: type: object default: null description: Asset metadata keyed by unit properties: data: type: object additionalProperties: $ref: '#/components/schemas/AssetMetadataEntryDto' default: '' description: >- Unit to its metadata. Every requested unit is present, in request order and in the caller's spelling; a unit that is unknown or has none of the three kinds of metadata maps to null. example: 9a2ec5c92daccbb269611a9eae7a40f9788d3f9c0229661b6234286f000de1406f766f3532: onchainMetadata: null cip68Metadata: name: OVO 52 image: ipfs://QmerWgPdvgPqS2KUo7jMKd2UUNt5D68iEmTJcTM4Ffv5XQ mediaType: image/gif cip68Version: 1 metadata: null AssetMetadataEntryDto: type: object default: null description: CIP-25, CIP-68 and token-registry metadata of one asset properties: onchainMetadata: type: string default: '' description: >- The asset's own CIP-25 entry from label 721 of its minting transaction: only this asset's object, not the whole label-721 body. Null when the minting transaction carries no entry for the asset. example: name: OVO 52 image: ipfs://QmerWgPdvgPqS2KUo7jMKd2UUNt5D68iEmTJcTM4Ffv5XQ cip68Metadata: type: string default: '' description: >- The CIP-68 reference datum's metadata map decoded to JSON. Byte strings are UTF-8 text where they are valid UTF-8 with no control characters, otherwise hex. Chunked lists (strings split into 64-byte pieces) are kept as arrays. Null when the asset has no reference datum. example: name: OVO 52 image: ipfs://QmerWgPdvgPqS2KUo7jMKd2UUNt5D68iEmTJcTM4Ffv5XQ mediaType: image/gif cip68Version: type: integer format: int32 default: '' description: >- The CIP-68 reference datum's version field. Null when there is no reference datum or it carries no integer version. example: 1 metadata: $ref: '#/components/schemas/AssetMetadataDto' default: '' description: >- The CIP-26 token-registry entry, the same object GET /api/assets/detailedInfo returns as metadata. Null when the asset is not in the registry. AssetMetadataDto: type: object properties: name: type: string description: type: string ticker: type: string url: type: string logo: type: string decimals: type: integer format: int32 securitySchemes: apiKeyAuth: type: apiKey description: >- ### API key (programmatic access — recommended) Send your API key in the `X-Api-Key` header. Keys start with `nxs_` and are created in the dashboard (or via **POST /api/keys** with a session JWT). Each key is scoped to **one chain and one network** (for example `CARDANO_MAINNET`), fixed at creation time. It cannot query a different network on the same chain, and it cannot query a different chain at all. A mismatched `network` parameter returns **400 Network Mismatch**. Create one key per chain and network under the same account. This is the credential most integrations should use. name: X-Api-Key in: header bearerAuth: type: http description: >- ### JWT session token (browser / mobile apps) A short-lived JWT issued by `/api/auth/login` or `/api/auth/device`, sent as `Authorization: Bearer `. This is the **session** credential for the web dashboard and mobile apps, not for server-to-server API access. For programmatic API access use an **API key** in the `X-Api-Key` header instead — do **not** put an `nxs_` API key in this Bearer field. scheme: bearer bearerFormat: JWT ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.