HyperSDK Starter Kit

HyperSDK Starter includes:

• Boilerplate VM based on MorpheusVM
• Universal frontend
• Metamask Snap wallet
• A quick start guide (this document)

Prerequisites

• Docker (recent version)
• Optional: Golang v1.22.5+
• Optional: NodeJS v20+
• Optional: Metamask Flask. Disable normal Metamask, Core wallet, and other wallets. Do not use your real private key with Flask.

0. Clone this repo

git clone https://github.com/ava-labs/hypersdk-starter-kit.git

1. Launch this example

Run: docker compose up -d --build devnet faucet frontend. This may take 5 minutes to download dependencies.

For devcontainers or codespaces, forward ports 8765 for faucet, 9650 for the chain, and 5173 for the frontend.

When finished, stop everything with: docker compose down

2. Explore MorpheusVM

This repo includes MorpheusVM, the simplest HyperSDK VM. It supports one action (Transfer) for moving funds and tracking balances.

2.1 Connect wallet

Open http://localhost:5173 to see the frontend.

We recommend using a Snap (requires Metamask Flask) for the full experience, but a temporary wallet works too.

2.2 Execute a read-only action

Actions can be executed on-chain (in a transaction) with results saved to a block, or off-chain (read-only). MorpheusVM has one action. Try executing it read-only. It shows expected balances of the sender and receiver. See the logic in actions/transfer.go.

2.3 Issue a transaction

Now, write data to the chain. Click "Execute in transaction". All fields are pre-filled with default values.

After mining, the transaction appears in the right column. This column shows all non-empty blocks on the chain.

2.4 Check Logs

Logs are located inside the Docker container. To view them, you'll need to open a bash terminal inside the container and navigate to the folder with the current network:

docker exec -it devnet bash -c "cd /root/.tmpnet/networks/latest_morpheusvm-e2e-tests && bash"

This isn’t the best developer experience, and we’re working on improving it.

3. Add Your Own Custom Action

Think of actions in HyperSDK like functions in EVMs. They have inputs, outputs, and execution logic.

Let's add the Greeting action. This action doesn’t change anything; it simply prints your balance and the current date. However, if it's executed in a transaction, the output will be recorded in a block on the chain.

3.1 Create an Action File

Place the following code in actions/greeting.go. The code includes some comments, but for more details, check out the docs folder in HyperSDK.

package actions

import (
	"context"
	"fmt"
	"time"

	"github.com/ava-labs/avalanchego/ids"

	"github.com/ava-labs/hypersdk-starter-kit/consts"
	"github.com/ava-labs/hypersdk-starter-kit/storage"
	"github.com/ava-labs/hypersdk/chain"
	"github.com/ava-labs/hypersdk/codec"
	"github.com/ava-labs/hypersdk/state"
	"github.com/ava-labs/hypersdk/utils"
)

// Please see chain.Action interface description for more information
var _ chain.Action = (*Greeting)(nil)

// Action struct. All "serialize" marked fields will be saved on chain
type Greeting struct {
	Name string `serialize:"true" json:"name"`
}

// TypeID, has to be unique across all actions
func (*Greeting) GetTypeID() uint8 {
	return consts.HiID
}

// All database keys that could be touched during execution.
// Will fail if a key is missing or has wrong permissions
func (g *Greeting) StateKeys(actor codec.Address) state.Keys {
	return state.Keys{
		string(storage.BalanceKey(actor)): state.Read,
	}
}

// The "main" function of the action
func (g *Greeting) Execute(
	ctx context.Context,
	_ chain.Rules,
	mu state.Mutable, // That's how we read and write to the database
	timestamp int64, // Timestamp of the block or the time of simulation
	actor codec.Address, // Whoever signed the transaction, or a placeholder address in case of read-only action
	_ ids.ID, // actionID
) (codec.Typed, error) {
	balance, err := storage.GetBalance(ctx, mu, actor)
	if err != nil {
		return nil, err
	}
	currentTime := time.Unix(timestamp/1000, 0).Format("January 2, 2006")
	greeting := fmt.Sprintf(
		"Hi, dear %s! Today, %s, your balance is %s %s.",
		g.Name,
		currentTime,
		utils.FormatBalance(balance),
		consts.Symbol,
	)

	return &GreetingResult{
		Greeting: greeting,
	}, nil
}

// How many compute units to charge for executing this action. Can be dynamic based on the action.
func (*Greeting) ComputeUnits(chain.Rules) uint64 {
	return 1
}

// ValidRange is the timestamp range (in ms) that this [Action] is considered valid.
// -1 means no start/end
func (*Greeting) ValidRange(chain.Rules) (int64, int64) {
	return -1, -1
}

// Result of execution of greeting action
type GreetingResult struct {
	Greeting string `serialize:"true" json:"greeting"`
}

// Has to implement codec.Typed for on-chain serialization
var _ codec.Typed = (*GreetingResult)(nil)

// TypeID of the action result, could be the same as the action ID
func (g *GreetingResult) GetTypeID() uint8 {
	return consts.HiID
}

3.2 Register the Action

Now, you need to make both the VM and clients (via ABI) aware of this action.

To do this, register your action in vm/vm.go after the line ActionParser.Register(&actions.Transfer{}, nil):

ActionParser.Register(&actions.Greeting{}, nil),

Then, register its output after the line OutputParser.Register(&actions.TransferResult{}, nil):

OutputParser.Register(&actions.GreetingResult{}, nil),

3.3 Rebuild Your VM

docker compose down -t 1; docker compose up -d --build devnet faucet frontend

3.4 Test Your New Action

HyperSDK uses ABI, an autogenerated description of all the actions in your VM. Thanks to this, the frontend already knows how to interact with your new action. Every action you add will be displayed on the frontend and supported by the wallet as soon as the node restarts.

Now, enter your name and see the result:

You can also send it as a transaction, but this doesn't make much sense since there’s nothing to write to the chain's state.

3.5 Next Steps

Congrats! You've just created your first action for HyperSDK.

This covers nearly half of what you need to build your own blockchain on HyperSDK. The remaining part is state management, which you can explore in storage/storage.go. Dive in and enjoy your journey!

4. Develop a Frontend

1. If you started anything, bring everything down: docker compose down
2. Start only the devnet and faucet: docker compose up -d --build devnet faucet
3. Navigate to the web wallet: cd web_wallet
4. Install dependencies and start the dev server: npm i && npm run dev

Make sure ports 8765 (faucet), 9650 (chain), and 5173 (frontend) are forwarded.

Learn more from npm:hypersdk-client and the web_wallet folder in this repo.

Notes

• You can launch everything without Docker:
  • Faucet: go run ./cmd/faucet/
  • Chain: ./scripts/run.sh, and use ./scripts/stop.sh to stop
  • Frontend: npm run dev in web_wallet
• Be aware of potential port conflicts. If issues arise, docker rm -f $(docker ps -a -q) will help.
• For VM development, you don’t need to know JavaScript—you can use an existing frontend, and all actions will be added automatically.
• If the frontend works with an ephemeral private key but doesn't work with the Snap, delete the Snap, refresh the page, and try again. The Snap might be outdated.
• Instead of using ./build/morpheus-cli commands, please directly use go run ./cmd/morpheus-cli/ for the CLI.
• Always ensure that you have the hypersdk-client npm version and the golang github.com/ava-labs/hypersdk version from the same commit of the starter kit. HyperSDK evolves rapidly.