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Published 8 days ago • verified publishernemorixpay.com
SDKFlutter
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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.

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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.

0.2.2-dev #

Phase 3 continues: fungible token transfers.

Added #

  • CryptoTransferTransaction.addTokenTransfer(TokenId, AccountId, int, {int? expectedDecimals}): transfers fungible tokens between accounts, in the same transaction as HBAR transfers if desired
    • expectedDecimals is OPTIONAL; when set, the network verifies the token's actual decimals match before applying the transfer, guarding against decimals changing between building and executing the transaction
  • example/phase3/token_transfer_example.dart: end-to-end example transferring a token between a treasury and a second account, including a correct expectedDecimals usage and a local error case
  • 18 new unit tests in crypto_transfer_transaction_test.dart (setters, per-token sum-to-zero validation, expectedDecimals conflict detection, serialization, buildBody() integration)

Notes #

  • Hedera has no separate token transfer transaction type; all transfers (HBAR, fungible tokens, NFTs) use the same CryptoTransferTransaction/TransferTransaction. This version extends the SDK's existing class rather than introducing a new one.
  • expectedDecimals is tied to the whole set of transfers for a given token, not to each individual transfer entry. If addTokenTransfer() is called multiple times for the same token with conflicting non-null expectedDecimals values, the SDK throws ArgumentError locally rather than silently picking one. No official guidance was found for this specific edge case; this is a deliberately conservative choice.
  • NFT transfers (addNftTransfer()) are deferred to v0.2.4-dev.
  • While building the live example, found that AccountBalanceQuery (from Phase 2) only exposes HBAR balance, not per-token balances. Extending it is planned for v0.2.6-dev (token queries).

Official References #

Verified #

Live on Hedera testnet: created a treasury account and a fungible token, created and associated a second account (Bob), transferred 25.00 DEMO treasury -> Bob (SUCCESS), 10.00 DEMO Bob -> treasury (SUCCESS), and a further 1.00 DEMO with expectedDecimals set (SUCCESS). Confirmed the conflicting-expectedDecimals case is caught locally, before any network call.

Status #

Phase 3 in progress: fungible token transfers implemented and verified live on testnet.
Not ready for production use.
Next: mint / burn (v0.2.3-dev).

0.2.1-dev #

Phase 3 continues: account-to-token association.

Added #

  • TokenAssociateTransaction: associates an account with one or more HTS tokens, required before that account can send or receive them
    • setAccountId() (required), addTokenId() (required, at least one; can be called multiple times)
  • TokenDissociateTransaction: dissociates an account from one or more HTS tokens; the account MUST have a zero balance of each token or the transaction resolves to TRANSACTION_REQUIRES_ZERO_TOKEN_BALANCES
    • setAccountId() (required), addTokenId() (required, at least one; can be called multiple times)
  • example/phase3/token_associate_example.dart: end-to-end example creating a token, creating an unassociated account, associating it, then dissociating it
  • 34 new unit tests: token_associate_transaction_test.dart and token_dissociate_transaction_test.dart (defaults, setters, toBytes() serialization, buildBody() integration confirming tokenAssociate/tokenDissociate oneof routing)
  • 600 total unit tests passing

Notes #

  • Official docs list a setHighVolume() property (HIP-1313) for TokenAssociateTransaction. Regenerating the SDK's Protobuf definitions did not surface a corresponding field on TokenAssociateTransactionBody, and the actively maintained hiero-ledger/hiero-sdk-java reference implementation does not reference one either. This is left out of the SDK for now and will be revisited once confirmed on the Protobuf side.

Official References #

Verified #

Live on Hedera testnet: created a treasury account and a fungible token, created a second unassociated account, associated it with the token (SUCCESS), then dissociated it with a zero balance (SUCCESS). No maxTransactionFee override was needed, unlike TokenCreateTransaction.

Status #

Phase 3 in progress: account-to-token association implemented and verified live on testnet.
Not ready for production use.
Next: token transfers (v0.2.2-dev).

0.2.0-dev #

Phase 3 begins: Hedera Token Service (HTS), fungible token creation.

Added #

  • TokenCreateTransaction: creates a new fungible or non-fungible token, with all 22 fields from the official token creation reference
    • Required: tokenName, tokenSymbol, treasuryAccountId
    • Optional: decimals, initialSupply, adminKey, kycKey, freezeKey, wipeKey, supplyKey, pauseKey, feeScheduleKey, metadataKey, freezeDefault, expirationTime, autoRenewAccountId, autoRenewPeriod, tokenMemo, tokenType, supplyType, maxSupply, metadata
    • Token keys accept any HederaKey (a single PublicKey, HederaKeyList, or HederaThresholdKey), enabling multi-sig control over token administration
  • TokenId.toProto(): converts to the Protobuf TokenID representation, following the same pattern as AccountId.toProto()
  • example/phase3/token_create_example.dart: end-to-end example creating a treasury account and a fungible token ("USD Bar" / USDB) with a supply key
  • 66 new unit tests: token_create_transaction_test.dart, covering defaults, setters, toBytes() serialization for all 22 fields (including a HederaThresholdKey as a token key), and buildBody() integration
  • 566 total unit tests passing

Changed #

  • BREAKING: Transaction.executeGrpc() now receives a raw ClientChannel instead of a pre-built CryptoServiceClient; each subclass constructs the specific gRPC service client it needs (CryptoServiceClient for account/HBAR transactions, TokenServiceClient for token transactions). Updated AccountCreateTransaction, AccountUpdateTransaction, AccountDeleteTransaction, and CryptoTransferTransaction accordingly. This unblocks token transactions now and Hedera Consensus Service (HCS) transactions in a future phase.

Fixed #

  • PublicKey.toProtoKey() (via HederaKey) now correctly encodes ECDSA keys with the eCDSASecp256k1 Protobuf field; previously affected token admin/supply/etc. keys the same way it had previously affected account keys before the v0.1.4-dev fix

Verified #

  • Live on Hedera testnet: created a treasury account, generated a supply key, and created a fungible token ("USD Bar" / USDB, 2 decimals, 100 initial supply) — confirmed SUCCESS status and correct token ID via HashScan (see example/phase3/token_create_example.dart)
  • Confirmed token creation requires a higher maxTransactionFee than account creation (the inherited 2 HBAR default triggers INSUFFICIENT_TX_FEE), since it includes a CryptoTransfer to move the initial supply to the treasury per official docs

Status #

Phase 3 started: fungible token creation implemented and verified live on testnet.
Not ready for production use.
Next: account-to-token association (v0.2.1-dev).

0.1.4-dev #

Phase 2 extension: multi-signature accounts, plus a critical node-routing fix carried over from v0.1.3-dev.

Added #

  • HederaKey: interface for anything that can serve as a Hedera account's authorization key (lib/src/crypto/hedera_key.dart)
    • toProtoKey(): converts to the Protobuf Key representation
  • PublicKey now implements HederaKey
  • HederaKeyList: N-of-N key list, requiring all keys to sign (lib/src/crypto/hedera_key_list.dart); supports nested HederaKeyList/HederaThresholdKey entries
  • HederaThresholdKey: M-of-N threshold key, requiring at least threshold of keys to sign; validates threshold is between 1 and keys.length at construction; supports nesting
  • AccountCreateTransaction.setKey() and AccountUpdateTransaction.setKey() now accept any HederaKey (a single PublicKey, HederaKeyList, or HederaThresholdKey), not only a single PublicKey
  • HederaClient.channelFor(HederaNode): creates a gRPC channel connected to a specific node's endpoint
  • HederaClient.resolveNode(): resolves the node for a transaction, either an explicit nodeAccountId (looked up in the live node list) or via selectNode() round-robin
  • example/phase2/multi_sig_example.dart: end-to-end 2-of-3 multi-signature example (create account, sign with 2 of 3 keys, execute a transfer)
  • 26 new unit tests: hedera_key_test.dart (25 tests) plus updates to AccountCreateTransaction/AccountUpdateTransaction coverage
  • 502 total unit tests passing

Fixed #

  • Critical: fixed INVALID_NODE_ACCOUNT errors introduced in v0.1.3-dev. HederaClient.selectNode()'s round-robin wrote a dynamic nodeAccountID into each TransactionBody, but the gRPC connection used to submit it (HederaClient.channel) always connected to a single static generic hostname, regardless of which node was selected. When the selected node didn't match whichever node the static connection actually reached, the network rejected the transaction. This affected Transaction.execute() calls intermittently, not only multi-signature transactions. Fixed by connecting via HederaClient.channelFor() to the specific node resolved for each transaction attempt, including on retry/failover.
  • PublicKey.toProtoKey() (via the new HederaKey interface) now correctly uses the eCDSASecp256k1 Protobuf field for ECDSA keys; previously, AccountCreateTransaction/AccountUpdateTransaction always hardcoded the ed25519 field, silently mis-encoding ECDSA account keys

Verified #

  • 2-of-3 multi-signature account created and used end-to-end on Hedera testnet: account creation, signing a transfer with exactly 2 of 3 keys, and successful execution, all confirmed live (see example/phase2/multi_sig_example.dart)
  • INVALID_NODE_ACCOUNT fix confirmed by the same live run

Status #

Phase 2 extension complete: multi-signature account support (HederaKeyList/HederaThresholdKey) implemented and verified live on testnet; the v0.1.3-dev node-routing bug is resolved.
Not ready for production use.
Next: Phase 3 - Hedera Token Service (HTS) (v0.2.0-dev).

0.1.3-dev #

Phase 2 extension: multi-node load balancing with retry/failover.

Added #

  • HederaNode: model representing a single consensus node (account ID + gRPC endpoint)
  • HederaClient.selectNode(): round-robin node selection over a dynamically fetched node list
  • HederaClient._getNodeList(): fetches the live node list from the Mirror Node REST API (/api/v1/network/nodes), cached for 24 hours; filters each node's service_endpoints by the port matching the active network (50211 insecure, 50212 TLS for mainnet); falls back to the static 0.0.3 node if the Mirror Node is unreachable
  • RetryPolicy: configurable retry policy for transient node/network failures (lib/src/client/retry_policy.dart)
    • isRetryable(Object error): retries GrpcError codes unavailable, deadlineExceeded, internal; never retries business errors like HederaStatusException (e.g. INVALID_SIGNATURE), since those fail identically on any node
    • backoffFor(int attempt): exponential backoff, capped at maxBackoff
    • HederaClient.setRetryPolicy()/retryPolicy: configure per client
  • HederaConstants.defaultMaxRetryAttempts: defaults to 5
  • Transaction.execute(): now retries transient failures per the active RetryPolicy, rotating to a new node between attempts when the SDK still holds the signing key (operator auto-sign path); for pre-signed transactions (sign()/signWith() called before execute()), retries against the same node instead, since the SDK no longer holds the private key needed to re-sign for a new node
  • example/phase2/node_selection_check.dart: manual verification script for node selection behavior
  • example/phase2/retry_behavior_check_example.dart: manual verification script covering 4 retry/failover scenarios (transient recovery, exhausted attempts, non-retryable business errors, pre-signed same-node retry)
  • 43 new unit tests: retry_policy_test.dart (18 tests), transaction_retry_test.dart (7 tests), plus updates to existing buildBody/buildSignedTransaction coverage
  • 475 total unit tests passing

Changed #

  • BREAKING: Transaction.buildBody() and Transaction.buildSignedTransaction() are now async (return Future), since they may call HederaClient.selectNode()
  • Transaction.buildBody(): uses client.selectNode() instead of the hardcoded AccountId.fromString('0.0.3') default when no nodeAccountId is explicitly set

Verified #

  • Real Mirror Node fetch and round-robin confirmed manually against Hedera testnet: rotates through real nodes 0.0.3–0.0.9 with matching real IPs, wraps around correctly, caching confirmed (only first call hits the network)
  • Retry/failover behavior confirmed manually across all 4 scenarios (see retry_behavior_check_example.dart), including that business errors are never retried and pre-signed transactions correctly skip re-signing

Status #

Phase 2 extension complete: multi-node load balancing (fetch + round-robin) and retry/failover both implemented and verified.
Not ready for production use.
Next: multi-signature support - KeyList with M-of-N threshold (v0.1.4-dev), before starting Phase 3 (HTS).

0.1.2-dev #

Phase 2 complete: ECDSA(secp256k1) signing support, for EVM-compatible accounts.

Added #

  • PrivateKey.derivePublicKey(): ECDSA(secp256k1) public key derivation using pointycastle's ECDomainParameters('secp256k1'); returns the compressed 33-byte form (0x02/0x03 prefix)
  • PrivateKey.sign(): ECDSA(secp256k1) signing via ECDSASigner with RFC 6979 deterministic k generation and low-S normalization (s <= n/2), as required by Hedera; returns the raw 64-byte (r + s) signature
  • PublicKey.fromBytes(): accepts 33-byte compressed ECDSA public keys
  • PublicKey.toDerString(): DER encoding for ECDSA public keys
  • PublicKey.verify(): ECDSA(secp256k1) signature verification
  • PublicKey.fromString(): recognizes DER-encoded and raw hex ECDSA public keys, alongside the existing ED25519 formats
  • HederaConstants.ecdsaPublicKeyPrefix: DER prefix for ECDSA public keys
  • ECDSA examples in public_key_example.dart and private_key_example.dart
  • 32 new unit tests in private_key_test.dart and public_key_test.dart covering ECDSA sign, derivePublicKey, and verify (mirroring existing ED25519 coverage, plus low-S normalization and compression prefix checks)
  • 5 new unit tests in transaction_test.dart verifying SignaturePair routes to the correct field by key type, including a mixed-signer transaction with both ED25519 and ECDSA signatures
  • 450 total unit tests passing

Fixed #

  • ECDSA sign()/verify() were hashing the message with SHA-256 instead of the Keccak-256 required by HIP-222 for EVM compatibility; now use pointycastle's KeccakDigest(256)
  • Transaction.buildSignedTransaction() and Transaction.execute() always built SignaturePair with the ed25519 field regardless of key type, silently misrouting ECDSA signatures into the wrong protobuf oneof field; _signatures now tracks PublicKeyType per entry and branches to eCDSASecp256k1 accordingly

Status #

Phase 2 complete: ECDSA(secp256k1) signing implemented and verified via unit tests, alongside the existing ED25519 support.
Live testnet integration verification for ECDSA (account creation, signing, receipt confirmation) deferred to next session.
Not ready for production use.
Next: multi-node load balancing (v0.1.3-dev).

0.1.1-dev #

Transaction query completeness: public receipt and record query classes.

Added #

  • TransactionReceiptQuery: public query class to poll the receipt of any Hedera transaction by ID, including transactions not executed by the caller
    • setTransactionId(TransactionId): sets the transaction ID to query
    • toBytes(): serializes to TransactionGetReceiptQuery Protobuf
    • execute(HederaClient): polls every 2 seconds until SUCCESS or timeout (30 seconds); returns TransactionReceipt with status, accountId, and tokenId
  • TransactionRecordQuery: public query class to retrieve the full record of a completed Hedera transaction
    • setTransactionId(TransactionId): sets the transaction ID to query
    • toBytes(): serializes to TransactionGetRecordQuery Protobuf
    • execute(HederaClient): polls getTxRecordByTxID() every 2 seconds until the record is available or timeout (30 seconds); returns TransactionRecord with fee, consensus timestamp, status, accountId, tokenId, and full HBAR transfer list
  • TransactionResponse.getRecord(HederaClient): polls the network for the full transaction record; replaces UnimplementedError
  • TransactionRecord: expanded model with new fields:
    • consensusTimestamp: exact consensus time as DateTime in UTC
    • status: final transaction status (e.g. SUCCESS)
    • accountId: new account ID for AccountCreateTransaction
    • tokenId: new token ID for TokenCreateTransaction
    • transfers: list of HBAR transfers with accountId and amount
  • 24 new unit tests (409/409 -> 433/433 total passing)

Changed #

  • TransactionReceiptQuery and TransactionRecordQuery renamed from TransactionGetReceiptQuery and TransactionGetRecordQuery to avoid naming collision with Protobuf-generated classes on Ubuntu CI
  • transaction_receipt_query.dart and transaction_record_query.dart renamed accordingly

Status #

Phase 2 complete: full transaction query pipeline implemented. TransactionReceiptQuery, TransactionRecordQuery, and getRecord()
all available and verified.
Not ready for production use.
Next: ECDSA signing (v0.1.2-dev).

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.

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verified publishernemorixpay.com

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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.

Homepage
Repository (GitHub)
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Topics

#hedera #blockchain #hbar #flutter #payments

License

Apache-2.0 (license)

Dependencies

bip39, convert, cryptography, fixnum, flutter, grpc, http, meta, pointycastle, protobuf, web_socket_channel

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