Quickstart

1

Create a Session

Start a new simulation session over a slot range.

• startSlot / endSlot: simulation range (inclusive).

• accountEvents (optional): stream updates for the listed accounts.

• signerFilter (optional): skip historical transactions signed by these addresses.

• preloadPrograms (optional): preload program accounts before execution.

This method requires an X-API-Key to be passed in the header.

// via websocket to `ws(s)://<host>/backtest`
{
  "method": "createBacktestSession",
  "params": {
    "startSlot": 123456,
    "endSlot": 234567,
    "accountEvents": ["addr..."],
    "signerFilter": ["addr..."],
    "preloadPrograms": ["addr..."],
  }
}

The server also emits an initial slotNotification for startSlot, followed by readyForContinue when the session is ready.

{
  "method": "sessionCreated",
  "params": {
    "sessionId": "<session_id>",
    "rpcEndpoint": "/backtest/<session_id>"
  }
}

2

Send Transactions

There are two supported paths for custom transactions:

• RPC path:

  • Send Solana transactions via sendTransaction to http(s)://<host>/backtest/<session_id>.

  • These execute immediately in the current slot after the historical block transactions.

• WebSocket path:

  • Include base64-encoded transactions in the continue request.

  • These execute in a batch, and the simulation also advances to the next slot.

  • See the section below.

Execution order per slot:

1. Historical block transactions.

2. User transactions submitted via RPC sendTransaction.

3. User transactions submitted in the continue batch.

See API Reference for the full list of supported Solana RPC methods.

3

3. Advance Slots

The simulator starts at startSlot and waits for an explicit continue before proceeding to subsequent slots.

• advanceCount: number of slots to execute before pausing again for user action, defaults to 1 when omitted.

• transactions: custom transactions.

• modifyAccountStates: account overrides applied before execution.

// via websocket to `/backtest/<session_id>`
{
  "method": "continue",
  "params": {
    "advanceCount": 1,
    "transactions": ["<base64_encoded_transaction>"],
    "modifyAccountStates": {
      "addr...": {
        "data": {
          "data": "<base64_bytes>",
          "encoding": "base64"
        },
        "executable": false,
        "lamports": 33594,
        "owner": "11111111111111111111111111111111",
        "space": 80
      }
    }
  }
}

During a continue, the server emits status updates (e.g. decodedTransactions, appliedAccountModifications, executedBlockTransactions, programAccountsLoaded), slotNotification events as slots advance, and readyForContinue when it is safe to send the next request.

4

Close a Session

// via websocket to `/backtest/<session_id>`
{
  "method": "closeBacktestSession"
}

This returns a success response and removes the session.

5

Account Updates

Any account registered in accountEvents streams real-time updates during execution.

{
  "method": "accountNotification",
  "params": {
    "pubkey": "addr...",
    "result": {
      "context": { "slot": 123457 },
      "value": {
        "data": {
          "data": "<base64_bytes>",
          "encoding": "base64"
        },
        "executable": false,
        "lamports": 33594,
        "owner": "11111111111111111111111111111111",
        "rentEpoch": 100,
        "space": 80
      }
    }
  }
}

result is null if the account was removed.

6

Subscriptions

The per-session WebSocket (/backtest/<session_id>) supports standard Solana-style subscriptions, including:

• accountSubscribe

• programSubscribe

• signatureSubscribe

• slotSubscribe

• logsSubscribe

See API Reference for the full list of supported Solana subscription methods.

Notes for Strategy Teams

• Use preloadPrograms + status: programAccountsLoaded if you need deterministic startup before your first continue.

• If you need rapid iteration, use advanceCount > 1 to fast-forward while still receiving slot notifications.