> ## Documentation Index
> Fetch the complete documentation index at: https://agora402.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Prerequisites: What You Need Before Running Agora402

> Everything you need before running Agora402: Node.js 20+, a Hedera testnet ECDSA account, and an optional LLM API key for inference.

Before you install Agora402, make sure your development environment meets the requirements below. Most of the setup takes only a few minutes: Node.js and Git are standard tools you likely already have, a free Hedera testnet account takes under two minutes to create, and the buyer account is provisioned for you automatically during setup. LLM credentials are optional — a built-in mock mode lets you explore the full payment flow without any inference key.

## Software Requirements

You need the following tools installed on your machine before proceeding.

| Tool           | Minimum Version    | Notes                                                                                      |
| -------------- | ------------------ | ------------------------------------------------------------------------------------------ |
| **Node.js**    | 20+                | Includes `npm`. Install from [nodejs.org](https://nodejs.org) or via your version manager. |
| **npm**        | Bundled with Node  | Used for workspace commands like `npm run setup:buyer`.                                    |
| **TypeScript** | —                  | Listed as a `devDependency`; installed automatically by `npm install`.                     |
| **Git**        | Any recent version | Required to clone the repository.                                                          |

<Tip>
  Use a version manager such as [nvm](https://github.com/nvm-sh/nvm) or [fnm](https://github.com/Schindua/fnm) to keep Node pinned to 20+ without affecting other projects.
</Tip>

## Hedera Testnet Account

Agora402 runs on the Hedera network. You need one ECDSA-keyed testnet account before you start — this becomes the **seller** account that receives payments and signs registry messages. The **buyer** account is created for you automatically later by `npm run setup:buyer`.

<Steps>
  <Step title="Create a free testnet account">
    Go to [portal.hedera.com](https://portal.hedera.com) and sign up or log in. The portal's built-in faucet provides free testnet HBAR — no credit card or mainnet funds required.
  </Step>

  <Step title="Choose ECDSA key type">
    When the portal prompts you for a key type, select **ECDSA**. Agora402's payment flow uses `@x402/hedera`, which requires ECDSA keys for signing Hedera `TransferTransaction` objects.
  </Step>

  <Step title="Download your credentials">
    Copy the **Account ID** (in the format `0.0.xxxxx`) and the **ECDSA private key** (a hex string beginning with `0x`). Store them securely — you will paste them into your `.env` file in the next section.
  </Step>
</Steps>

<Note>
  You only need to create this one account manually. The buyer account is generated from it by `npm run setup:buyer`, which transfers 100 HBAR from the seller to fund the new account.
</Note>

## LLM Provider (Optional)

Agora402's inference endpoint (`POST /v1/infer`) acts as a paid LLM proxy. You can connect it to a real model or run in `mock` mode with no external credentials.

Set the `LLM_PROVIDER` environment variable to choose your provider, then supply the matching key and model identifier:

| Variable            | Purpose                                                                                                      |
| ------------------- | ------------------------------------------------------------------------------------------------------------ |
| `LLM_PROVIDER`      | `groq`, `anthropic`, or `mock`                                                                               |
| `GROQ_API_KEY`      | Required when `LLM_PROVIDER=groq`. Get a free key at [console.groq.com](https://console.groq.com).           |
| `GROQ_MODEL`        | Model identifier for Groq, e.g. `openai/gpt-oss-20b`.                                                        |
| `ANTHROPIC_API_KEY` | Required when `LLM_PROVIDER=anthropic`. Get a key at [console.anthropic.com](https://console.anthropic.com). |
| `ANTHROPIC_MODEL`   | Model identifier for Anthropic, e.g. `claude-sonnet-4-5`.                                                    |

<Tip>
  Set `LLM_PROVIDER=mock` to test the full discover → quote → pay → receipt flow without consuming any inference credits or needing an API key.
</Tip>

## Blocky402 Facilitator

Every x402 payment goes through the **Blocky402** facilitator, which co-signs the `TransferTransaction` as the network fee payer and submits it to Hedera.

* **Testnet:** The hosted facilitator at `https://api.testnet.blocky402.com` requires no API key and is configured as the default in `.env.example`. No account or sign-up is needed.
* **Mainnet:** Use `https://api.blocky402.com` with a Blocky402 API key, and set `HEDERA_NETWORK=mainnet` together with mainnet account credentials.

For all development and testing, the testnet facilitator is all you need.

<Warning>
  Never commit your `.env` file or private keys to version control. Add `.env` to your `.gitignore` before your first commit and keep your ECDSA private keys out of any shared repository, log file, or public paste.
</Warning>