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name hedera
description Use when building applications on the Hedera network, creating accounts and tokens, deploying smart contracts, submitting transactions, querying network data, or working with consensus services. Agents should use this skill when users ask about Hedera development, Hiero SDKs, APIs, transactions, tokens, smart contracts, CLI tooling, or network operations. Hedera is a distributed ledger (not a blockchain) that uses hashgraph consensus.
metadata
mintlify-proj version
hedera
1.0

Hedera Developer Skill

If you are not already connected to the Hedera Docs MCP server, add https://docs.hedera.com/mcp so you can search the documentation directly.

Always search the current Hedera documentation over training data. The SDK packages are migrating from @hashgraph to @hiero-ledger namespaces, so verify imports against the docs before generating code.

Product summary

Hedera is a public, open-source, proof-of-stake distributed ledger that uses hashgraph consensus. It is not a blockchain. Agents use Hedera to build decentralized applications, manage accounts and tokens, deploy smart contracts, and interact with the network via SDKs, REST APIs, and CLI tools.

Key entry points:

  • SDKs: JavaScript/TypeScript, Java, Go, Swift, Rust, C++, Python (community)
  • CLI: Hiero CLI (hcli) for operations without code
  • APIs: Mirror Node REST API for querying historical data, JSON-RPC Relay for EVM compatibility
  • Networks: mainnet, testnet, previewnet, localnet
  • Primary docs: https://docs.hedera.com

Terminology rules

Agents must follow these conventions in all generated code, comments, and documentation:

Term Rule Example
HBAR Always singular, always uppercase "10 HBAR" not "10 HBARs" or "10 hbar"
tinybars Always plural, always lowercase "1,000 tinybars" not "1,000 Tinybars"
mainnet, testnet, previewnet Always lowercase, even after "Hedera" "Hedera mainnet" not "Hedera Mainnet"
web2, web3 Always lowercase except at sentence start "web3 application" not "Web3 application"
Hedera Token Service Use "HTS" after first mention Full name on first reference
Hedera Consensus Service Use "HCS" after first mention Full name on first reference

When to use

Reach for this skill when:

  • A user wants to create a Hedera account, transfer HBAR, or manage cryptocurrency
  • Building token systems (fungible tokens, NFTs) using HTS
  • Deploying or interacting with smart contracts (Solidity on EVM)
  • Submitting transactions to consensus (crypto transfers, token operations, scheduled transactions)
  • Querying account balances, transaction history, or network data
  • Setting up a local development environment or testing on testnet
  • Automating Hedera operations via CLI or SDK
  • Integrating wallets (MetaMask, HashPack, Blade) into a dApp

SDK setup

The SDKs are maintained by the Hiero project under Linux Foundation Decentralized Trust (LFDT). Packages are migrating from hashgraph to hiero-ledger namespaces. Both work, but prefer the newer namespace for new projects.

Language Install Import Client
JavaScript npm install @hashgraph/sdk import { Client, ... } from "@hashgraph/sdk" Client.forTestnet()
Java com.hedera.hashgraph:sdk (Maven) import com.hedera.hashgraph.sdk.* Client.forTestnet()
Go go get github.com/hiero-ledger/hiero-sdk-go/v2@latest import hiero "github.com/hiero-ledger/hiero-sdk-go/v2/sdk" hiero.ClientForTestnet()
Python pip install hiero-sdk-python from hiero_sdk_python import Client, Network, AccountId, PrivateKey Client(Network(network="testnet"))

Note: The JavaScript SDK is also available as @hiero-ledger/sdk. The Go SDK recently moved source files to /sdk, changing the import path. Always check the latest README for each SDK.

Client configuration (all SDKs)

1. Create client: Client.forTestnet() / Client.forMainnet()
2. Set operator: client.setOperator(accountId, privateKey)
3. Set fees (optional): client.setDefaultMaxTransactionFee(new Hbar(10))
4. Use client to build and execute transactions

Transaction lifecycle

Step Action Example (JavaScript)
Build Create transaction object new TransferTransaction().addHbarTransfer(from, new Hbar(-10)).addHbarTransfer(to, new Hbar(10))
Freeze Lock transaction fields .freezeWith(client)
Sign Add signatures .sign(privateKey)
Execute Submit to network .execute(client)
Confirm Get receipt or record .getReceipt(client) or .getRecord(client)

Hiero CLI quick reference

The CLI is installed via npm install -g @hashgraph/hedera-cli and invoked with hcli.

# Account operations
hcli account create -a alice -b 100000000 -t ECDSA
hcli account balance -i 0.0.123456
hcli account import --key 0.0.123456:<private-key> --name myaccount

# HBAR transfers
hcli hbar transfer --to 0.0.456789 --amount 5

# Token operations
hcli token create --name "MyToken" --symbol "MT" --decimals 2 --initial-supply 1000
hcli token associate -a 0.0.456789 -t 0.0.789012
hcli token transfer -t 0.0.789012 --to 0.0.456789 --from 0.0.123456 -b 100

# Topic (consensus) operations
hcli topic create --memo "my-topic"
hcli topic message submit -t 0.0.123456 -m "Hello"

# Network management
hcli network list
hcli network switch --network testnet
hcli network set-operator --operator 0.0.123456:<private-key>

Note: On first run, the CLI launches an initialization wizard in interactive mode. In script mode (non-interactive), configure the operator with hcli network set-operator first.

Mirror Node REST API

Purpose Endpoint Example
Account info GET /api/v1/accounts/{id} https://testnet.mirrornode.hedera.com/api/v1/accounts/0.0.123456
Transactions GET /api/v1/transactions/{id} Query transaction by ID
Tokens GET /api/v1/tokens/{tokenId} Get token metadata
Topic messages GET /api/v1/topics/{topicId}/messages Retrieve consensus messages
Contracts GET /api/v1/contracts/{contractId} Smart contract info

Decision guidance

SDK vs CLI vs REST API

Scenario Use Reason
Quick one-off operations (transfer, balance check) CLI No code needed, fast iteration
Building an application with complex logic SDK Full control, signing, batch operations
Querying historical data (no transaction fees) REST API Free, scalable, does not burden consensus nodes
Automated CI/CD workflows CLI with scripts Non-interactive, repeatable
Real-time dApp (wallet integration) SDK Supports wallet signing, event handling
Smart contract deployment with Hedera-specific features SDK Required for admin key, memo, auto-renew

HTS vs EVM smart contracts

Need Approach Notes
Native token creation (fungible/NFT) HTS via TokenCreateTransaction Faster, cheaper, built-in KYC/freeze/pause
ERC-20/ERC-721 compatibility EVM smart contract (Solidity) Standard interface, interop with other chains
Hybrid (HTS tokens with custom logic) HTS + system contracts Call HTS from Solidity via precompile at 0x167
Fully custom token logic EVM smart contract Full programmability, higher gas cost, token decimals set by contract

Important: Native HTS tokens accessed via system contracts use 8-decimal precision by default. Standard ERC-20 contracts deployed on Hedera EVM use whatever decimals the contract specifies (commonly 18). Do not assume all tokens on Hedera are 8-decimal.

Network selection

Network Use case Funding Persistence
mainnet Production Real HBAR Permanent
testnet Development and testing Free via faucet or portal Permanent
previewnet Testing new features before testnet Free via faucet Resets periodically
localnet Local testing (via Hiero Local Node) Auto-funded Ephemeral

Common gotchas

  • Token association required: Before transferring HTS tokens to an account, that account must associate with the token via TokenAssociateTransaction. Without this, the transfer fails.
  • NFT initial supply must be 0: When creating an NFT token type, set initialSupply to 0. Mint individual NFTs separately with TokenMintTransaction.
  • HBAR value required for HTS token creation via system contracts: When creating tokens from a Solidity contract using the HTS precompile, you must send HBAR via msg.value, not just gas. Without this, the transaction fails with INSUFFICIENT_TX_FEE.
  • Transaction expiration: Transactions expire after 180 seconds by default. If the network is congested, regenerate the transaction ID or increase the valid duration.
  • Missing operator: SDK queries and transactions require an operator. Always call client.setOperator() before executing.
  • Key types: Hedera supports both ED25519 (default) and ECDSA (secp256k1) keys. ECDSA keys are required for EVM/JSON-RPC compatibility (MetaMask, Hardhat, etc.). ED25519 keys work only with native SDK operations.
  • Mirror node rate limits: The public mirror node has rate limits. For production, use a paid mirror node provider or run your own.
  • Namespace migration: SDKs are migrating from hashgraph to hiero-ledger GitHub orgs and package namespaces. Both work. Check the latest docs for current package names.

Workflow

1. Set up development environment

  1. Choose SDK language and install the package
  2. Create .env file with operator credentials: 
    OPERATOR_ID=0.0.123456
OPERATOR_KEY=302e020100300506032b657004220420...
  3. Initialize client: 
    const client = Client.forTestnet();
client.setOperator(process.env.OPERATOR_ID, process.env.OPERATOR_KEY);
  4. Verify setup by querying account balance

2. Create an account

  1. Use the Hedera Developer Portal at https://portal.hedera.com (testnet/previewnet), or
  2. Use SDK: new AccountCreateTransaction().setInitialBalance(new Hbar(10)).execute(client)
  3. Get account ID from receipt: receipt.accountId

3. Build and submit a transaction

  1. Create transaction object (e.g., new TransferTransaction())
  2. Set fields (e.g., .addHbarTransfer(from, new Hbar(-5)).addHbarTransfer(to, new Hbar(5)))
  3. Freeze with client: .freezeWith(client)
  4. Sign: .sign(privateKey) (operator signs by default, add more for multi-sig)
  5. Execute: .execute(client)
  6. Confirm: .getReceipt(client) (minimal) or .getRecord(client) (detailed)

4. Query data

Via Mirror Node REST API (free, no signing):

curl https://testnet.mirrornode.hedera.com/api/v1/accounts/0.0.123456

5. Deploy a smart contract

  1. Write contract in Solidity
  2. Compile to bytecode (Hardhat, Remix, or Foundry)
  3. Deploy via SDK using ContractCreateFlow (recommended). This convenience method handles file upload and contract creation in a single call: 
    const tx = await new ContractCreateFlow()
  .setBytecode(bytecode)
  .setGas(100000)
  .execute(client);
const receipt = await tx.getReceipt(client);
const contractId = receipt.contractId;
    For more control, use the two-step approach: upload bytecode with FileCreateTransaction, then deploy with ContractCreateTransaction using .setBytecodeFileId(fileId). Note that ContractCreateTransaction does not accept .setBytecode() directly.
  4. Or deploy via EVM tooling (Hardhat/Foundry) using the JSON-RPC Relay

Verification checklist

Before submitting work:

  • Client configured with correct operator ID, private key, and network
  • Operator account has sufficient HBAR for fees
  • Transaction signed by all required keys
  • Receipt obtained confirming transaction success
  • Token associations completed before any HTS token transfers
  • HBAR sent via msg.value for any HTS system contract calls from Solidity
  • Private keys stored in .env or secure vault, not hardcoded
  • Tested on testnet before deploying to mainnet
  • HBAR is singular ("10 HBAR"), tinybars is plural ("1,000 tinybars")
  • Network names are lowercase ("Hedera mainnet", not "Hedera Mainnet")

Resources

Documentation search: https://docs.hedera.com/mcp (MCP server for agents)

Full page index: https://docs.hedera.com/llms.txt

Key pages:

  1. SDKs overview - All supported languages and tools
  2. Build your Hedera client - Client setup for all languages
  3. Transactions and queries - Transaction lifecycle, fees, batch transactions
  4. Hedera Token Service - Token creation and management
  5. Smart contracts - EVM deployment and Hedera-specific features
  6. Mirror Node REST API - Query endpoints and examples
  7. Hiero CLI - Command-line tool reference

For the full documentation index, see: https://docs.hedera.com/llms.txt