# HelloWorld Contract

Owner: instructor
Reference: ../../prd.json story D2

This folder holds the single Solidity contract used in the workshop: `HelloWorld.sol`. The contract is deliberately minimal: one public string state variable, no functions, no events.

## Primary path: Deploy on Remix VM (in-browser chain)

This is the path every student follows. No external network is required.

1. Open https://remix.ethereum.org in any modern browser.
2. Create a new file in the `contracts/` panel called `HelloWorld.sol`.
3. Paste the contents of `HelloWorld.sol` into the editor.
4. Click "Solidity Compiler" in the left panel and click `Compile HelloWorld.sol`. The status indicator should turn green AND show "compiled successfully".
5. Click "Deploy & run transactions". In the "Environment" dropdown, select `Remix VM (Cancun)` or whichever Remix VM the page offers.
6. Click `Deploy`.
7. In the "Deployed Contracts" panel, expand the contract, click `greeting`. The output is `Hello, Class`.

Time budget: under 30 seconds end to end on a clean profile.

## Level-up only: Deploy on Sepolia

This path is OPTIONAL. It only works for students who arrived in class with a funded MetaMask wallet on Sepolia. See ../pre_class/checklist.md for the pre-class steps.

1. In Remix, in the "Deploy & run transactions" panel, change the "Environment" to `Injected Provider - MetaMask`.
2. Confirm MetaMask is on Sepolia (top-left dropdown of MetaMask).
3. Click `Deploy`. MetaMask prompts for confirmation; approve.
4. Wait for the transaction to mine (15 to 30 seconds on Sepolia).
5. Copy the contract address from the "Deployed Contracts" panel.
6. Open https://sepolia.etherscan.io in a new tab, paste the address into the search bar, view the contract.

The level-up succeeds if Etherscan shows the contract address with a green-checkmark "Contract" tag.

## Security warning

See ../instructor_kit/security_brief.md.

TEST WALLET ONLY, NEVER REUSE THIS SEED. The wallet you create or use in class is for learning only. It has zero monetary value, was set up on classroom infrastructure, and may be exposed.