pryntr-tutorial

Emoji minting on Injective EVM - a Slack bot that lets users mint emoji tokens as ERC-1155 NFTs.

Built on the injective-evm-foundry template.

Architecture

Slack ──► /brrr :fire: @alice ──► Bot (TypeScript) ──► Pryntr.sol (ERC-1155) ──► Injective EVM

• Pryntr.sol : ERC-1155 contract. Each emoji is a token type. 24h cooldown per sender.
• Bot : TypeScript Slack bot (Bolt). Derives deterministic addresses from Slack user IDs, calls the contract, returns tx links.
• Local devnet : Dockerized Injective node + Blockscout explorer for development.

Prerequisites

• Foundry
• Docker
• Node.js 18+

Quick Start -Local Development

1. Install Foundry dependencies

forge install OpenZeppelin/openzeppelin-contracts

2. Build and test contracts

make build
make test

3. Start local devnet

make local-init    # One-time: initialize chain, create funded accounts
make local-start   # Start Injective node + Blockscout explorer

After local-init, you'll see two pre-funded dev accounts with mnemonics. Derive the EVM private key:

cast wallet private-key --mnemonic "copper push brief egg scan entry inform record adjust fossil boss egg comic alien upon aspect dry avoid interest fury window hint race symptom"

4. Deploy the contract

Create .env with the dev1 private key:

cp .env.example .env
# Edit .env — set PRIVATE_KEY to the dev1 EVM key from step 3

make local-deploy

Note the deployed contract address from the output.

5. Configure and run the bot

cd bot
cp .env.example .env

Edit bot/.env — set PRIVATE_KEY and PRYNTR_ADDRESS from the previous steps, then generate a salt for address derivation:

openssl rand -hex 32

Paste the output as ADDRESS_SALT in bot/.env. This salt prevents outsiders from mapping user IDs to on-chain addresses. Generate it once and don't change it after minting — changing it orphans existing user addresses.

npm install

CLI mode (no Slack required):

npx tsx src/cli.ts mint :fire: alice bob
npx tsx src/cli.ts portfolio bob
npx tsx src/cli.ts cooldown alice

Slack bot mode (set SLACK_BOT_TOKEN, SLACK_APP_TOKEN, SLACK_SIGNING_SECRET in .env):

npm run dev

6. View in the explorer

Open http://localhost:3000 to see transactions in the local Blockscout explorer.

Explorers

Injective has two explorers serving different purposes:

Explorer	URL	Shows
Cosmos explorer	https://testnet.explorer.injective.network	Cosmos-native txs, validators, governance, IBC
EVM explorer (Blockscout)	https://testnet.blockscout.injective.network	EVM txs, contract source, ABI interaction, token balances

For EVM contract development, use the Blockscout explorer. It shows contract creation addresses, verified source code, and lets you interact with contracts directly. The Cosmos explorer shows the same transactions but from the Cosmos side — it won't display EVM-specific details like deployed contract addresses.

For local development, the Blockscout instance runs at http://localhost:3000.

Project Structure

pryntr-tutorial/
├── foundry.toml              # Foundry config (Solidity 0.8.28, Cancun EVM)
├── Makefile                  # Build/test/deploy targets
├── .env.example              # Configuration template
├── src/
│   └── Pryntr.sol            # ERC-1155 emoji minting contract
├── test/
│   └── Pryntr.t.sol          # 11 test cases
├── script/
│   └── Deploy.s.sol          # Deployment script
├── vendor/
│   ├── fetch.sh              # Fetch Injective precompile contracts
│   └── injective/            # Vendored precompile interfaces
├── local-dev/
│   ├── docker-compose.yml    # Injective node + Blockscout
│   └── setup.sh              # Chain initialization
└── bot/
    ├── package.json
    ├── tsconfig.json
    ├── .env.example
    └── src/
        ├── index.ts           # Slack command handlers
        ├── cli.ts             # CLI mode (no Slack required)
        ├── contract.ts        # Ethers.js contract interaction
        └── config.ts          # Environment configuration

Makefile Targets

Target	Description
make build	Compile contracts
make test	Run test suite (in-memory EVM)
make local-init	Initialize local chain (one-time)
make local-start	Start node and explorer
make local-stop	Stop all local services
make local-clean	Remove chain data and explorer DB
make local-deploy	Deploy Pryntr to local devnet
make bot-install	Install bot dependencies
make bot-dev	Run bot in dev mode (requires Slack)
make cli CMD='...'	Run CLI (e.g. CMD='mint :fire: alice bob')
make testnet-deploy	Deploy Pryntr to testnet
make testnet-verify	Verify contract on Blockscout

Testnet Deployment

Update .env:

RPC_URL=https://k8s.testnet.json-rpc.injective.network/
PRIVATE_KEY=0x...   # Testnet-funded wallet

make testnet-deploy
# Note the contract address, then:
# CONTRACT_ADDRESS=0x... make testnet-verify

Update the bot's .env to point RPC_URL to testnet and set the new PRYNTR_ADDRESS.