hedera_flutter_sdk 0.1.0-dev

The first native Flutter/Dart SDK for the Hedera network. Pure Dart, no platform channels. Supports HBAR, HTS, HCS, and Mirror Node. Built for mobile and desktop.

Changelog

All notable changes to hedera_flutter_sdk will be documented here.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

0.1.0-dev

Phase 2 complete: gRPC transaction execution, account management, and HBAR transfers verified on Hedera testnet.

Added

• Transaction.buildBody(HederaClient): builds a complete TransactionBody Protobuf with transactionID (operator account + nanosecond timestamp), nodeAccountID (default 0.0.3), transactionFee, transactionValidDuration, and memo; calls applyToBody() for the transaction-specific fields
• Transaction.applyToBody(TransactionBody): abstract method implemented by each subclass to set its specific field on the TransactionBody Protobuf (cryptoCreateAccount, cryptoTransfer, etc.)
• Transaction.buildSignedTransaction(HederaClient): serializes TransactionBody to bodyBytes, wraps with SignatureMap into a SignedTransaction Protobuf
• Transaction.execute(HederaClient): full gRPC execution pipeline: builds and caches bodyBytes, signs with operator or custom key, constructs SignedTransaction and Transaction envelope, submits via gRPC, verifies nodeTransactionPrecheckCode, returns TransactionResponse
• Transaction.signWith(PrivateKey, HederaClient): signs the transaction with a non-operator private key using the correct cached bodyBytes; use when a non-operator account needs to authorize a transaction
• Transaction.setPayerAccountId(AccountId): sets the account that pays transaction fees; if not set, the operator account is used by default
• Transaction._buildBodyBytes(HederaClient): internal cache for serialized TransactionBody bytes; guarantees byte consistency across signWith() and execute() calls
• TransactionResponse.getReceipt(HederaClient): polls CryptoService.getTransactionReceipts() every 2 seconds (up to 15 attempts / 30 seconds) until consensus is reached; returns TransactionReceipt with status, accountId, and tokenId; throws HederaStatusException on non-SUCCESS status; throws TimeoutException after 30 seconds
• AccountCreateTransaction.applyToBody(): sets cryptoCreateAccount with autoRenewPeriod = 7,776,000s (90 days, required by Hedera)
• AccountUpdateTransaction.applyToBody(): sets cryptoUpdateAccount
• AccountDeleteTransaction.applyToBody(): sets cryptoDelete
• CryptoTransferTransaction.applyToBody(): sets cryptoTransfer; validates that transfer amounts sum to zero
• Transaction.executeGrpc(CryptoServiceClient, Transaction): abstract method returning TransactionResponse Protobuf; each subclass routes to the correct CryptoServiceClient method
• HederaClient.channel: lazy-initialized ClientChannel; insecure on port 50211 for testnet/previewnet, TLS on port 50212 for mainnet
• HederaClient.cryptoClient: returns CryptoServiceClient connected to the active network node
• HederaClient.close(): shuts down the gRPC channel and releases resources
• Integration test infrastructure:
  • test/integration/integration_test_helper.dart: reads operator credentials from HEDERA_OPERATOR_ID and HEDERA_OPERATOR_KEY
  • test/integration/transactions/account_create_transaction_test.dart: 2 tests verified on Hedera testnet (account 0.0.9358959 created)
  • test/integration/transactions/account_setup_test.dart: utility test to create funded testnet accounts and print credentials
  • test/integration/transactions/crypto_transfer_transaction_test.dart: operator-signed HBAR transfers with getReceipt() SUCCESS
  • test/integration/transactions/crypto_transfer_sign_test.dart: non-operator signing via signWith() and setPayerAccountId(); reads Alice credentials from HEDERA_ALICE_ID and HEDERA_ALICE_KEY
• New examples:
  • example/phase2/quick_start_example.dart: simplest flow with bilingual comments (EN/ES)
  • example/phase2/account_lifecycle_example.dart: complete end-to-end flow - create Alice, create Bob, Alice transfers HBAR to Bob using her own key and paying her own fees; bilingual comments (EN/ES)
  • example/phase2/hedera_service_example.dart: HederaService pattern for Flutter apps with init() and dispose() lifecycle; bilingual comments (EN/ES)
• 45 new unit tests (363/363 -> 407/407 total passing)

Changed

• Transaction.execute(): refactored to sign bodyBytes (complete TransactionBody) instead of toBytes() (specific body only); fixes INVALID_SIGNATURE on Hedera nodes
• HederaClient.channel: switched from TLS to insecure for testnet and previewnet to avoid certificate verification issues in development
• example/hedera_flutter_sdk_example.dart: updated with GETTING STARTED, QUICK START, and PHASE OVERVIEW sections; documents Windows/macOS/Linux environment variable setup

Fixed

• INVALID_RENEWAL_PERIOD: added autoRenewPeriod to AccountCreateTransaction.applyToBody()
• INVALID_SIGNATURE: signing now uses cached bodyBytes from _buildBodyBytes() ensuring the signed bytes match exactly what the node receives in SignedTransaction
• TransactionId in TransactionResponse: now extracted from the built TransactionBody instead of DateTime.now(), ensuring correct timestamp for getReceipt() polling

Verified on Hedera Testnet

• Operator account: 0.0.9186292 (ED25519, testnet)
• Accounts created: 0.0.9358959, 0.0.9365895, 0.0.9367078, 0.0.9367079 (visible on HashScan)
• HBAR transfers: operator to receiver and Alice to Bob (non-operator signing with custom fee payer)
• All transactions visible at: https://hashscan.io/testnet/account/0.0.9186292/operations

Status

Phase 2 complete: full gRPC execution pipeline working end-to-end on Hedera testnet. Account creation, HBAR transfers, receipt polling, non-operator signing, and custom fee payers all verified.
Not ready for production use.
Next: Hedera Token Service (HTS) - Phase 3.

0.0.9-dev

Phase 2 in progress: HBAR transfers and EVM address compatibility.

Added

• CryptoTransferTransaction: transfers HBAR between Hedera accounts
  • addHbarTransfer(AccountId, Hbar), callable multiple times
  • transferCount getter
  • toBytes() validates that transfer amounts sum to zero before serializing via CryptoTransferTransactionBody Protobuf
  • throws ArgumentError if no transfers added or sum is not zero
• AccountId.evm() and AccountId.fromEvmAddress(): EVM-compatible address alias support (20-byte addresses, e.g. for MetaMask)
  • isEvmAddress getter
  • toString() handles both native (shard.realm.num) and EVM (0x...) formats
• AccountId.toProto(): centralizes AccountID Protobuf construction, correctly using the alias field for EVM accounts (oneof with accountNum)
• example/phase2/transaction_example.dart: expanded with AccountUpdateTransaction, AccountDeleteTransaction, and CryptoTransferTransaction examples
• example/phase2/query_example.dart: expanded with AccountInfoQuery example and updated full workflow preview
• 42 new unit tests (321/321 -> 363/363 total passing)

Changed

• AccountBalanceQuery, AccountInfoQuery, AccountUpdateTransaction, AccountDeleteTransaction, CryptoTransferTransaction: refactored to use AccountId.toProto() instead of manually constructing AccountID, reducing duplication and enabling transparent EVM alias support
• README.md: Current Features and Planned Features updated to reflect Phase 2 progress
• pubspec.yaml: version bumped to 0.0.9-dev

Status

Phase 2 in progress: Account Management CRUD cycle complete, HBAR transfers and EVM address alias support added.
Not ready for production use.
Next: gRPC execution (execute() via HederaClient).

0.0.8-dev

Phase 2 in progress: Account Management CRUD cycle completed.

Added

• AccountInfo: model representing full Hedera account information
  • accountId, key, balance, deleted, memo, receiverSignatureRequired, maxAutomaticTokenAssociations, ownedNfts
• AccountInfoQuery: queries full account information
  • setAccountId() (required)
  • toBytes() serializes via CryptoGetInfoQuery Protobuf
• AccountUpdateTransaction: updates an existing Hedera account
  • setAccountIdToUpdate() (required); all other fields optional
  • setKey(), setNewMemo(), setReceiverSignatureRequired(), setMaxAutomaticTokenAssociations()
  • Optional fields use Google Protobuf wrapper types (StringValue, BoolValue, Int32Value) to distinguish "not set" from falsy values
  • toBytes() serializes via CryptoUpdateTransactionBody Protobuf
• AccountDeleteTransaction: deletes an existing Hedera account
  • setAccountId() (required) - account to delete
  • setTransferAccountId() (required) - receives remaining HBAR balance
  • toBytes() serializes via CryptoDeleteTransactionBody Protobuf
• 61 new unit tests (321/321 total passing)

Changed

• pubspec.yaml: version bumped to 0.0.8-dev

Status

Phase 2 in progress: Account Management CRUD cycle completed (Create, Read, Update, Delete).
Not ready for production use.
Next: CryptoTransferTransaction.

0.0.7-dev

Phase 2 in progress: Cryptography and Account Management.

Added

• Transaction<T>: abstract base class for all Hedera transactions using Generic Self-Type pattern for fluent API chaining in any order
  • setNodeAccountId(), setMaxTransactionFee(), setMemo(), setValidDuration(), setTransactionId()
  • sign(), addSignature(), signWithOperator()
  • execute() stub (gRPC pending)
  • TransactionResponse, TransactionReceipt, TransactionRecord
• AccountCreateTransaction: creates a new Hedera account
  • setKey() (required), setInitialBalance(), setMaxAutomaticTokenAssociations(), setReceiverSignatureRequired()
  • toBytes() serializes via CryptoCreateTransactionBody Protobuf
• Query<R, T>: abstract base class for all Hedera queries using Generic Self-Type pattern; payment support pending (requires CryptoTransferTransaction)
• AccountBalanceQuery: queries HBAR balance of a Hedera account
  • setAccountId() (required)
  • toBytes() serializes via CryptoGetAccountBalanceQuery Protobuf
• example/: restructured into phase-based subfolders

Changed

• example/hedera_flutter_sdk_example.dart: refactored as entry point; imports phase2 examples
• pubspec.yaml: version bumped to 0.0.7-dev
• README.md: Phase 2 checklist updated with completed items

Status

Phase 2 in progress: Cryptography and Account Management.
Not ready for production use.
Next: CryptoTransferTransaction and AccountInfoQuery.

0.0.6-dev

Phase 2 in progress: Cryptography and Account Management.

Added

• HederaClient with forTestnet(), forMainnet(), forPreviewnet()
• Mnemonic.toPrivateKey(): HD key derivation from mnemonic via BIP-39 standard; supports optional passphrase; 12 and 24-word mnemonics
• Mnemonic.toLegacyPrivateKey(): legacy key derivation for 12 and 24-word mnemonics; 22-word legacy pending (UnsupportedError with reference to github.com/hashgraph/hedera-sdk-go)
• Official BIP-39 wordlists (2048 words each; English and Spanish)
• Mnemonic.fromString(): create Mnemonic from space-separated phrase
• Mnemonic.validate(): BIP-39 checksum validation for English and Spanish
• PrivateKey.derivePublicKey(): async ED25519 public key derivation
• HederaConstants: ASN.1/DER prefix constants
  • ed25519PrivateKeyPrefix (OID 1.3.101.112 - RFC 8410)
  • ecdsaPrivateKeyPrefix (OID 1.3.132.0.10)
  • ed25519PublicKeyPrefix
• README.md: Quick Guide expanded with PrivateKey and PublicKey sections

Changed

• README.md: Current Features updated with toPrivateKey and toLegacyPrivateKey
• README.md: Planned Features updated; 22-word legacy mnemonic marked pending

Status

Phase 2 in progress: Cryptography and Account Management.
Not ready for production use.
Next: Transaction base class and Account Management.

0.0.5-dev

Phase 2 in progress: Cryptography and Account Management.

Added

• PrivateKey: ED25519 and ECDSA key generation, import, and signing
  • generateED25519() using cryptography package
  • generateECDSA() using Random.secure()
  • fromBytes() with type parameter
  • fromString() supporting DER and raw hex
  • sign() for ED25519 via cryptography package
  • toDerString() and toHex() using ASN.1/DER prefix constants
  • toString() does not expose key bytes (security)
• PublicKey: derivation, import, and ED25519 signature verification
  • derivePublicKey() async derivation from PrivateKey
  • fromBytes() and fromString() supporting DER and raw hex
  • verify() for ED25519 signature verification
  • toDerString(), toHex(), toString() (safe to expose)
• HederaConstants: ASN.1/DER prefix constants for ED25519 and ECDSA
  • ed25519PrivateKeyPrefix (OID 1.3.101.112 - RFC 8410)
  • ecdsaPrivateKeyPrefix (OID 1.3.132.0.10)
  • ed25519PublicKeyPrefix
• cryptography ^2.9.0: added for ED25519 key generation and signing
• example/: Quick Start examples for Mnemonic, PrivateKey and PublicKey
• README.md: Quick Guide expanded with PrivateKey and PublicKey examples
• 54 new unit tests (155/155 total passing)

Changed

• README.md: Current Features updated with PrivateKey and PublicKey
• README.md: Planned Features updated; removed implemented items
• README.md: encoding issues fixed

Status

Phase 2 in progress: Cryptography and Account Management. Not ready for production use. Next: Mnemonic.toPrivateKey() HD key derivation and Account Management.

0.0.4-dev

Phase 2 started: Cryptography and Account Management.

Added

• Mnemonic: BIP-39 mnemonic generation and validation with generate24() and generate12() in English and Spanish
• Mnemonic.fromString(): create Mnemonic from space-separated phrase
• MnemonicLanguage: enum with english and spanish options
• Official BIP-39 English wordlist (2048 words)
• Official BIP-39 Spanish wordlist (2048 words); first Hedera SDK with native Spanish mnemonic support for LATAM users
• toSeed(): derives 64-byte seed via PBKDF2 with optional passphrase
• validate(): full BIP-39 checksum validation for English and Spanish
• 41 unit tests for Mnemonic (101/101 total passing)

Status

Phase 2 in progress: Cryptography and Account Management. Not ready for production use. Next: ED25519 and ECDSA key generation with pointycastle.

0.0.3-dev

Fix pana static analysis score from 50/160 to 130/160.

Fixed

• generate_proto.ps1: include auxiliary/ and state/ subdirectories to resolve missing URI imports in transaction.pb.dart
• pubspec.yaml: add explicit platform declarations (Android, iOS, macOS, Windows, Linux) excluding Web due to gRPC dart:io dependency
• analysis_options.yaml: exclude lib/src/proto/** from analyzer to suppress warnings in auto-generated Protobuf files

Changed

• pubspec.yaml: version bumped to 0.0.3-dev

Status

Phase 1 completed. Not ready for production use. pana score: 130/160. Phase 2 starting: Cryptography and Account Management.

0.0.2-dev

Phase 1 completed - SDK foundation and architecture.

Added

• HederaStatusException: typed exception for Hedera network errors
• HederaStatusCode: typed status codes from response_code.proto with common codes (SUCCESS, INSUFFICIENT_ACCOUNT_BALANCE, INVALID_SIGNATURE, TOKEN_NOT_ASSOCIATED, KYC_NOT_GRANTED, etc.)
• HederaConstants: protocol-level constants for ports, HBAR units, transaction limits, default fees, and network endpoints
• Unit tests for all core classes (60/60 passing)
• Protobuf code generation script (generate_proto.ps1)
• 335 Dart classes generated from 104 Hedera HAPI .proto files

Changed

• HederaClient: updated to use HederaConstants for endpoints, ports, and default fees instead of hardcoded values
• pubspec.yaml: shortened description for pub.dev compliance
• Flutter upgraded to 3.44.0

Status

Phase 1 completed. Not ready for production use. Phase 2 starting: Cryptography and Account Management.

0.0.1-dev

Initial SDK scaffold - Phase 1 in progress.

Added

• Flutter package structure with very_good_analysis linter
• Base model classes: AccountId, TokenId, TransactionId, Hbar
• HederaClient with forTestnet(), forMainnet(), forPreviewnet()
• HederaNetwork enum
• Crypto stubs: PrivateKey, PublicKey, Mnemonic (Phase 2)
• Unit tests: 20/20 passing
• GitHub Actions CI/CD pipeline
• pre_commit.ps1 for local verification

Status

Phase 1 in progress. Not ready for production use. Full feature set coming in v1.0.0.