> For the complete documentation index, see [llms.txt](https://docs-v4.nftx.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs-v4.nftx.io/api-reference/api-reference.md).

# Overview

The NFTX v4 API — a read-only REST interface for reading collections, listings, activity, prices, portfolios, and swap quotes.

The NFTX v4 API is a **read-only** REST interface over the protocol. Use it to read collection data, listings, activity, holders, prices, and user portfolios, and to fetch swap quotes and transaction calldata your own wallet then submits. It's the fastest way to build on NFTX without indexing the chain yourself.

{% hint style="info" %}
The API is **public and read-only** — no API key or authentication is required. Nothing here moves funds: swap endpoints return a quote and an unsigned payload that **your** wallet signs and submits.
{% endhint %}

## Base URL and chains

Every protocol route is scoped to a chain:

```
/v1/{chain}/...
```

`{chain}` is a numeric chain ID or one of its slug aliases. The API supports:

| Chain                             | Chain ID   | Aliases                                                      |
| --------------------------------- | ---------- | ------------------------------------------------------------ |
| Ethereum Mainnet                  | `1`        | `mainnet`, `ethereum`, `eth`                                 |
| Arbitrum One                      | `42161`    | `arbitrum`, `arbitrum-one`, `arb`, `arb-mainnet`             |
| Ink                               | `57073`    | `ink`, `ink-mainnet`                                         |
| Robinhood Chain                   | `4663`     | `robinhood`, `robinhood-chain`, `rh`                         |
| Ethereum Sepolia (testnet)        | `11155111` | `sepolia`, `eth-sepolia`, `ethereum-sepolia`                 |
| Robinhood Chain Testnet (testnet) | `46630`    | `robinhood-testnet`, `robinhood-chain-testnet`, `rh-testnet` |

For example, listing collections on Robinhood Chain is `GET /v1/4663/collections`, and on Ethereum Mainnet `GET /v1/1/collections` (or `GET /v1/ethereum/collections`).

{% hint style="info" %}
Requests for any chain outside this table return `400 UNSUPPORTED_CHAIN`. Base Mainnet (`8453`) and Base Sepolia (`84532`) are no longer served; their deployments still exist on-chain, and their addresses remain in [Deployment Addresses](/contracts/addresses.md).
{% endhint %}

## What's inside

| Group                                        | What it covers                                               |
| -------------------------------------------- | ------------------------------------------------------------ |
| [System](/api-reference/system.md)           | Health, readiness, protocol config and stats                 |
| [Collections](/api-reference/collections.md) | Collection data, tokens, holders, traits, prices, liquidity  |
| [Activity](/api-reference/activity.md)       | Global, collection-, token-, and user-scoped activity feeds  |
| [Listings](/api-reference/listings.md)       | Liquid and Dutch listings for a collection or a single token |
| [Search](/api-reference/search.md)           | Search across collections and tokens                         |
| [Users](/api-reference/users.md)             | Portfolio, balances, listings, escrow, votes, positions      |
| [Swaps](/api-reference/swaps.md)             | Quotes, approval checks, and executable swap calldata        |
| [Realtime](/api-reference/realtime.md)       | Streaming protocol events                                    |
| [Vaults](/api-reference/vaults.md)           | Vault creation preflight checks                              |
| [Test tokens](/api-reference/test-tokens.md) | Test-token metadata and images (testnet)                     |

## About this spec

The reference below is generated live from the NFTX v4 API's OpenAPI specification, served at [`nftx-v4-api-production.up.railway.app/openapi.json`](https://nftx-v4-api-production.up.railway.app/openapi.json). The API service emits this spec via its `openapi:emit` build step, so the reference stays in step with the deployed API.

{% hint style="info" %}
A point-in-time copy of the spec is also committed to this repository at [`api-reference/nftx-v4-api.json`](https://github.com/flayerlabs/nftx-v4-gitbook/tree/main/api-reference/nftx-v4-api.json) as an offline snapshot. The live endpoint above is the source of truth that the operation blocks render from.
{% endhint %}