Resources

Change Logs

Learn about the changes and updates in each version of the Hydra SDK

July 2026 — `bridge` v2.0.0 (`next` tag)

@hydra-sdk/bridge 2.0.0 retargets the bridge from hydra-node v1 to the v2 line (verified against 2.3.0). The bridge major version now tracks the hydra-node major version, and 1.x is end of life.

Published under the next dist-tag. latest still resolves to 1.3.2. Install with pnpm add @hydra-sdk/bridge@next.

💥 Breaking — hydra-node v2 removed the commit phase

v2 implements ADR-33: a head opens directly, with no commit phase to abort. Funds enter an open head through incremental deposits instead.

commands.abort() and HydraCommand.GetUTxO removed
commands.initSync() resolves on HeadIsOpen, not HeadIsInitializing
Tags removed: HeadIsInitializing, Committed, HeadIsAborted, CommitIgnored, GetUTxOResponse, PeerHandshakeFailure
HeadIsOpen is { headId, parties } — it no longer carries utxo
HeadIsFinalized.utxo renamed to finalizedUTxO
HydraHeadStatus drops Initializing and Final (Final never existed in any released hydra-node)
HydraHeadInfo is a discriminated union over Idle | Open | Closed
SubmitTxResponse rebuilt from Hydra.Chain.PostTxError
Greetings, InvalidInput and every ClientMessage carry no seq / timestamp

✨ New

Commands safeClose(), sideLoadSnapshot(), partialFanout()
submitL2Tx() — submits over POST /transaction and lets the node return the verdict, instead of racing WebSocket messages against a client timeout
pendingDeposits() and recoverDeposit() for the deposit lifecycle
getRawProtocolParameters() exposing costModels / protocolVersion for ExUnits budgeting under PV11
bridge.syncedStatus and bridge.nodeVersion; the bridge now fails fast on RejectedInputBecauseUnsynced instead of hanging until timeout

🐛 Found by testing against a live node

The v2 types were derived from the hydra Haskell source, then checked against a running hydra-node 2.3.0. That check found five defects a source read alone had missed:

Greetings.env has no signingKey — the node's ToJSON deliberately omits it
Greetings Maybe fields are omitted rather than null, so hydraHeadId / snapshotUtxo are optional
InvalidInput arrives with no tag; the connectors now stamp one so the payload union stays discriminated
POST /transaction takes the bare tx envelope, not { submitL2Tx: … }
Chain-waiting endpoints timed out client-side at 30s while the node works to its own 300s api-transaction-timeout — DELETE /commits reported failure for a recovery the node had completed

🧹 Housekeeping

The bridge's duplicated protocol-parameter constants are gone; it now uses @hydra-sdk/core, which carries the PV11 cost models. toProtocol() routes through castProtocol, so a zero utxoCostPerByte — what the node reports inside a head — is preserved rather than replaced by the L1 default.

See MIGRATION-v2.md for the full upgrade path.

July 2026 Release — `transaction` v1.2.0 · `core` v1.4.1 · `bridge` v1.3.2 · `cardano-wasm` v1.0.0 (Latest)

The headline is @hydra-sdk/transaction v1.2.0 — a memory-safety and features release for TxBuilder. @hydra-sdk/cardano-wasm also reaches its first stable v1.0.0.

🧠 Memory Safety — `@hydra-sdk/transaction`

WASM memory leak & progressive slowdown fixed: every @emurgo/cardano-serialization-lib object lives in WASM linear memory and is only reclaimed by .free(). CSL's FinalizationRegistry cleanup is non-deterministic and cannot keep up under a tight build loop, so the WASM heap grew unbounded and per-transaction build time degraded steadily. complete() now frees every internally-allocated CSL object deterministically after build_tx(). Measured result: flat WASM memory (~0 KB/iter) and steady throughput across 10,000 builds; 280 existing tests unchanged. Caller-supplied objects (datum / redeemer / script) are never freed.
completeCbor(): Promise<string> (new): builds the transaction and returns its CBOR hex, freeing the intermediate Transaction immediately — the leak-free path for high-volume workloads where you only need the serialized bytes. complete() still returns a live Transaction; the caller is responsible for calling .free() on it.
dispose() + [Symbol.dispose] (new): release all WASM memory held by a builder. Works with the using keyword (using tx = new TxBuilder()); recommended for high-volume / spike workloads instead of relying on the GC.

🚀 New Features — `@hydra-sdk/transaction`

Stake certificates are now built: registerStake(), deregisterStake(), and delegateStake() previously staged certificates that were silently dropped at build time — they are now applied via set_certs, so the built transaction actually contains the certificate(s). The stake credential is resolved from the bech32 reward (stake) address; an invalid reward address now throws instead of being ignored. PoolRegistration / PoolRetirement throw a clear "not supported yet" error.
totalCollateral() is now applied to the built transaction via set_total_collateral (previously the value was stored but never written).
Optional script exUnits evaluation: TxBuilder accepts an evaluator?: IEvaluator (plus a txEvaluationMultiplier? safety margin). When supplied and the transaction contains Plutus redeemers, complete() runs a second build pass — the draft transaction is evaluated to obtain real exUnits, those are written back into the redeemers (SPEND matched by input txHash#index, MINT by policy id), and the transaction is rebuilt so the fee is accurate. Without an evaluator (e.g. for Hydra, which has no on-chain script evaluation), behaviour is unchanged. The IEvaluator / EvalAction / Budget types mirror MeshJS for interoperability. Current limits: only SPEND and MINT budgets are remapped, and no offline evaluator is bundled yet — supply a provider-backed one (Blockfrost / Ogmios / Demeter) or a UPLC evaluator.

🐛 Bug Fixes — `@hydra-sdk/transaction`

Script-transaction fee fix: the builder config previously hardcoded ex_unit_prices to zero and ref_script_coins_per_byte to 15/1, so the script-execution fee component (priceMem·exMem + priceStep·exSteps) was omitted and reference-script pricing ignored the protocol params — under-funding script transactions. Both are now sourced from the protocol parameters (priceMem, priceStep, minFeeRefScriptCostPerByte). Non-script transfers were already correct.
reset() use-after-free fixed (the metadata container was freed but not recreated) and the constructor no longer double-allocates the underlying TransactionBuilder when params is supplied.

📦 `@hydra-sdk/cardano-wasm` v1.0.0 — first stable release

The WASM wrapper reaches v1.0.0. It selects the correct @emurgo/cardano-serialization-lib build via package.json exports conditions (browser → browser WASM, node → Node.js), with the asm.js fallback opt-in at the @hydra-sdk/cardano-wasm/asmjs subpath. Now that it is stable, pin it like any other dependency (^1.0.0).

🔧 `@hydra-sdk/core` v1.4.1 & `@hydra-sdk/bridge` v1.3.2

@hydra-sdk/bridge@1.3.2: syncs the updated Cardano v11 protocol parameters and cost models; depends on core@1.4.1 and cardano-wasm@1.0.0.
@hydra-sdk/core@1.4.1: dependency bump to @hydra-sdk/cardano-wasm@1.0.0 (patch; the v11 protocol-parameter defaults landed in 1.4.0).

Package	Current Version	Description
`@hydra-sdk/core`	1.4.1	Core library for building decentralized applications
`@hydra-sdk/transaction`	1.2.0	Transaction building and management utilities
`@hydra-sdk/bridge`	1.3.2	Bridge functionality for wallet connections
`@hydra-sdk/cardano-wasm`	1.0.0	Cardano WASM bindings and utilities
`@hydra-sdk/tsconfig`	0.0.4	Shared TypeScript configuration
`@hydra-sdk/eslint-config`	0.0.4	Shared ESLint configuration