# NFT collection · API reference · Femtos

> Metadata, tokens seen and 24 h activity of one collection. GET /v1/nfts/collections/{address} on Elysium and HyperEVM: parameters, response fields and a live call per layer.

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  (https://femtos.xyz/agents.md#agent-onboarding)
- Decimals are exact strings, times Unix milliseconds, addresses lowercase `0x`
- Whole API in one file: https://femtos.xyz/agents.md · OpenAPI: https://api.femtos.xyz/v1/openapi.json · Index: https://femtos.xyz/llms.txt
- Page with live calls: https://femtos.xyz/reference/nft-collection

## NFT collection — GET `/v1/nfts/collections/{address}`

Metadata, tokens seen and 24 h activity of one collection.

Layers: Elysium, HyperEVM. Not on HyperCore: served on Elysium and HyperEVM only.
Page with live calls: https://femtos.xyz/reference/nft-collection?layer=<elysium|hyperevm>

| Param | In | Example or values | Meaning |
|---|---|---|---|
| `address` | path | `<collection>` | Collection contract |
| `layer` | query | `elysium` (Elysium); `hyperevm` (HyperEVM) | EVM layer |

Elysium:

```bash
curl -H "Authorization: Bearer $FEMTOS_KEY" "https://api.femtos.xyz/v1/nfts/collections/<collection>?layer=elysium"
```

HyperEVM:

```bash
curl -H "Authorization: Bearer $FEMTOS_KEY" "https://api.femtos.xyz/v1/nfts/collections/<collection>?layer=hyperevm"
```

| Field | Type | Meaning |
|---|---|---|
| `layer` | string | Layer |
| `collection` | object | An NFT contract (one row per contract and standard): {address, standard, name, symbol, firstSeenBlock, firstSeenAt} |
| `standards` | string[] | Its standards (erc721, erc1155: a contract may emit both) |
| `tokens` | object | {count, capped} |
| `activity24h` | object | {from, to, fromBlock, toBlock, transfers, mints, burns, lastBlock} |
| `syncing` | true | Present while the layer syncs: data only up to dataUntil |
| `dataUntil` | ms | Indexed head time while the layer syncs |

## Related (NFTs)

- [Active NFT collections](https://femtos.xyz/reference/nft-collections.md) `GET /v1/nfts/collections`: Collections with the most transfers over the last 1 h or 24 h. (Elysium, HyperEVM)
- [Collection tokens](https://femtos.xyz/reference/nft-tokens.md) `GET /v1/nfts/tokens`: Tokens of a collection by id, with their owner and metadata URI. (Elysium, HyperEVM)
- [NFTs of a wallet](https://femtos.xyz/reference/nft-owned.md) `GET /v1/nfts/owned`: ERC-721 tokens owned and ERC-1155 balances of one address. (Elysium, HyperEVM)
- [NFT transfers](https://femtos.xyz/reference/nft-transfers.md) `GET /v1/nfts/transfers`: Transfers of a collection or one token, newest first. While HyperEVM syncs: the last 24 h or 7 d of indexed blocks. (Elysium, HyperEVM)

Every page: https://femtos.xyz/reference.md