> ## Documentation Index
> Fetch the complete documentation index at: https://docs.auth.near.org/llms.txt
> Use this file to discover all available pages before exploring further.

# Network configuration

> Every per-network value an integrator sets — NEAR RPC, contract ids, and Auth0 — for mainnet and testnet.

NEAR Auth runs on two networks: **testnet** for building and **mainnet** for production. Every value on this page is network-specific — swap the whole set together when you move an app from testnet to mainnet. Testnet uses shared credentials you can copy today; mainnet requires an [approved application](/home/apply).

<Note>
  Start on testnet with the values below — no sign-off needed. When you're ready to launch, [apply for production access](/home/apply) to get your own mainnet Auth0 `clientId`.
</Note>

***

## All values, side by side

Every setting your app needs, per network. The NEAR values feed `near-api-js` and the `FastAuthClient` config; the Auth0 values feed the [`JavascriptProvider`](/sdks/javascript-provider) (or `ReactNativeProvider`).

| Setting                 | Mainnet                        | Testnet                            |
| ----------------------- | ------------------------------ | ---------------------------------- |
| `networkId`             | `mainnet`                      | `testnet`                          |
| NEAR RPC (`nodeUrl`)    | `https://rpc.mainnet.near.org` | `https://rpc.testnet.near.org`     |
| `fastAuthContractId`    | `fast-auth.near`               | `fast-auth.testnet`                |
| `mpcContractId`         | `v1.signer`                    | `v1.signer-prod.testnet`           |
| Auth0 `domain`          | `login.auth.near.org`          | `login.testnet.fast-auth.com`      |
| Auth0 `signingAudience` | `auth0.jwt.fast-auth.near`     | `auth0.jwt.fast-auth.testnet`      |
| Auth0 `clientId`        | *your approved application*    | `np8paqIpMWmNbzT4xAvOOapZBjsOpptl` |

<Info>
  `domain` and `signingAudience` are **optional** on the provider — the SDK ships the correct defaults for the `network` you pass, so you only set them to override a custom Auth0 setup. `clientId` is always required.
</Info>

<Warning>
  There is no shared mainnet `clientId`. The testnet `clientId` above is a public, shared demo credential — never point a production app at it. Your mainnet `clientId` comes from your own approved application. [Apply for production access →](/home/apply)
</Warning>

***

## What each value is for

* **`networkId`** — the NEAR network your app talks to. Selects the RPC, contracts, and MPC signer for that environment.
* **NEAR RPC (`nodeUrl`)** — the JSON-RPC endpoint `near-api-js` uses to build the connection you pass into `FastAuthClient`.
* **`fastAuthContractId`** — the account of the on-chain [NEAR Auth contract](/protocol/contracts/fast-auth) that verifies the Auth0 JWT and requests the signature.
* **`mpcContractId`** — the [MPC signer](/protocol/concepts/mpc) contract that produces the signature from distributed key shares. Full contract addresses live on the [Mainnet](/resources/mainnet) and [Testnet](/resources/testnet) reference pages.
* **Auth0 `domain`** — the Auth0 tenant that hosts the login flow.
* **Auth0 `signingAudience`** — the audience the issued JWT is scoped to; on-chain, the [Auth0 Guard](/protocol/concepts/auth0) checks this `aud` value.
* **Auth0 `clientId`** — identifies your application to Auth0.

***

## Ready-to-copy config

Drop one of these into your app and read from it. The `near` block configures the [Browser SDK](/sdks/browser-sdk) client; the `auth0` block configures the [JavaScript provider](/sdks/javascript-provider).

<CodeGroup>
  ```json config.testnet.json theme={"theme":{"light":"github-light","dark":"github-dark"}}
  {
    "networkId": "testnet",
    "near": {
      "nodeUrl": "https://rpc.testnet.near.org",
      "fastAuthContractId": "fast-auth.testnet",
      "mpcContractId": "v1.signer-prod.testnet"
    },
    "auth0": {
      "network": "testnet",
      "domain": "login.testnet.fast-auth.com",
      "signingAudience": "auth0.jwt.fast-auth.testnet",
      "clientId": "np8paqIpMWmNbzT4xAvOOapZBjsOpptl"
    }
  }
  ```

  ```json config.mainnet.json theme={"theme":{"light":"github-light","dark":"github-dark"}}
  {
    "networkId": "mainnet",
    "near": {
      "nodeUrl": "https://rpc.mainnet.near.org",
      "fastAuthContractId": "fast-auth.near",
      "mpcContractId": "v1.signer"
    },
    "auth0": {
      "network": "mainnet",
      "domain": "login.auth.near.org",
      "signingAudience": "auth0.jwt.fast-auth.near",
      "clientId": "your-approved-application-client-id"
    }
  }
  ```
</CodeGroup>

## Wiring it into the SDK

Once you've picked a config, only three things flow into the SDK: the `network` and `clientId` for the provider, and the `fastAuthContractId` / `mpcContractId` for the client. The NEAR connection is built from `networkId` and `nodeUrl`.

<CodeGroup>
  ```ts testnet.ts theme={"theme":{"light":"github-light","dark":"github-dark"}}
  import { FastAuthClient } from "@fast-auth-near/browser-sdk";
  import { JavascriptProvider } from "@fast-auth-near/javascript-provider";
  import { connect } from "near-api-js";

  const provider = new JavascriptProvider({
    network: "testnet",
    clientId: "np8paqIpMWmNbzT4xAvOOapZBjsOpptl",
    // domain and signingAudience are optional — SDK defaults match the network
  });

  const { connection } = await connect({
    networkId: "testnet",
    nodeUrl: "https://rpc.testnet.near.org",
  });

  const client = new FastAuthClient(provider, connection, {
    fastAuthContractId: "fast-auth.testnet",
    mpcContractId: "v1.signer-prod.testnet",
  });
  ```

  ```ts mainnet.ts theme={"theme":{"light":"github-light","dark":"github-dark"}}
  import { FastAuthClient } from "@fast-auth-near/browser-sdk";
  import { JavascriptProvider } from "@fast-auth-near/javascript-provider";
  import { connect } from "near-api-js";

  const provider = new JavascriptProvider({
    network: "mainnet",
    clientId: "your-approved-application-client-id",
    // domain and signingAudience are optional — SDK defaults match the network
  });

  const { connection } = await connect({
    networkId: "mainnet",
    nodeUrl: "https://rpc.mainnet.near.org",
  });

  const client = new FastAuthClient(provider, connection, {
    fastAuthContractId: "fast-auth.near",
    mpcContractId: "v1.signer",
  });
  ```
</CodeGroup>

<Tip>
  Keep both configs in your repo and select one by an environment variable so switching networks is a single toggle — never a code change.
</Tip>

***

## Keep exploring

<CardGroup cols={2}>
  <Card title="Mainnet reference" icon="globe" href="/resources/mainnet" horizontal arrow>
    Deployed contract addresses, RPC, and explorer for production.
  </Card>

  <Card title="Testnet reference" icon="globe" href="/resources/testnet" horizontal arrow>
    The same lookup for the testnet environment.
  </Card>

  <Card title="Apply for production" icon="rocket" href="/home/apply" horizontal arrow>
    Get your own mainnet Auth0 credentials.
  </Card>
</CardGroup>