Midnight .NET SDK

A C# / .NET SDK for the Midnight Network — work in progress, focused on what's possible without the WASM-bound JS SDK.

What works in pure C#

• Wallet creation & HD derivation — BIP39 24-word mnemonic, BIP32 derivation with Midnight's coin type (m/44'/2400'/account'/role/index). Bit-for-bit compatible with 1AM / Lace / the official JS SDK.
• Indexer sync — connects to the Midnight indexer over graphql-transport-ws and consumes the three sync streams in parallel (zswapLedgerEvents, dustLedgerEvents, unshieldedTransactions).
• Unshielded UTXO tracking — full live state of NIGHT balance and UTXOs for any address, including registeredForDustGeneration flag. The indexer decodes unshielded data server-side, so no WASM is needed.
• Address tx history — full sent/received history for any unshielded address, including counterparty addresses.

What needs the JS SDK (Node worker)

Anything that builds a transaction (mint, transfer, contract call) requires the WASM ledger lib for binary serialization, ZK transcript, and shielded output handling. The SDK can't do this in pure C#.

For these operations the SDK shells out to a tiny Node helper (worker/midnight-worker.mjs in the nmkr-midnight-api project) over stdin/stdout JSON-RPC. The Node process is short-lived — it spawns, builds the tx, submits it, and exits.

The pool architecture — keep a set of dust-funded wallets always-synced in the API server's watch list, then mint in parallel via HTTP — is the production-ready alternative for high-volume minting.

Project structure

src/Midnight.Sdk/
├── MidnightConfig.cs          Network config (preview / preprod / mainnet)
├── Hd/
│   ├── Roles.cs               BIP44 roles (NightExternal / Internal / Dust / Zswap / Metadata)
│   ├── Bip39Helper.cs         Mnemonic generate / recover (24 words)
│   └── HdWallet.cs            BIP32 derivation with Midnight path
├── Wallet/
│   └── MidnightWallet.cs      High-level wallet (create / recover / info)
├── Sync/
│   ├── IndexerClient.cs       graphql-transport-ws WebSocket client
│   ├── SyncSubscriptions.cs   GraphQL queries (Zswap / Dust / Unshielded)
│   ├── IndexerEvents.cs       Event DTOs
│   ├── UnshieldedState.cs     UTXO tracking + NIGHT balance
│   └── WalletSync.cs          Sync orchestrator (3 parallel streams)
├── Api/
│   └── MidnightApiClient.cs   HTTP client for the nmkr-midnight-api REST API
├── Bridge/
│   └── NodeWorker.cs          Spawns Node worker for one-shot tx operations
└── Wasm/
    └── LedgerWasm.cs          (Skeleton — direct WASM loading is not feasible
                                with wasm-bindgen output without a JS host)

demo/                          Console app exercising every command

Quick start

dotnet build

cd demo

# create a fresh wallet
dotnet run -- create

# show derived keys for a seed
dotnet run -- info <hex-seed>

# live indexer sync for an address (no seed needed)
dotnet run -- sync mn_addr_preprod1xy...

# transfer NIGHT (uses Node worker)
dotnet run -- transfer <senderSeed> <toAddr> 1 preview

# mint via HTTP API
dotnet run -- bulk-mint-api <ownerSeed> <contractAddr> 10 http://localhost:3002 /tmp/dust-pool.json

dotnet run without arguments lists every available command.

Verified compatibility with the JS SDK

The HD-derived role keys produce bit-for-bit identical bytes as the JS @scure/bip32 + bip39 pair used by the official wallet SDK. A wallet created in C# can be opened in 1AM / Lace, and vice versa.

Status

• Wallet creation, HD derivation, mnemonic
• Indexer WebSocket sync (3 parallel subscriptions)
• Unshielded UTXO state, NIGHT balance, dust-registration flag
• NIGHT transfer (via Node worker)
• NFT collection deploy + mint (via Node worker)
• HTTP client for nmkr-midnight-api
• Direct WASM ledger lib bindings (research; wasm-bindgen output is heavily JS-coupled and not straightforward to host in C#)
• Shielded balance / state (needs WASM)
• Pure-C# tx building (would require Midnight to publish the binary tx format spec)

License

Apache-2.0 — same as the underlying Midnight wallet-sdk we draw from.