same block bundling

Understanding how Flap Bundle achieves same-block transaction inclusion.

How It Works

1

Pre-sign transactions

All transactions in a bundle are pre-signed locally with correct nonces.

2

Broadcast simultaneously

All raw signed transactions are sent to the RPC at the same moment via Promise.all.

3

Inclusion by validators

Validators pick up the transactions and include them in the next available block(s).

Transaction Independence

Each transaction in the bundle uses a different account:

• Deploy TX → deployer wallet (nonce N)

• Fee TX → deployer wallet (nonce N+1)

• Buy TX 1 → bundle wallet 1 (nonce 0)

• Buy TX 2 → bundle wallet 2 (nonce 0)

• ...

Since each buy uses a different wallet address with its own nonce, they can all be included in the same block without conflicts.

RPC Types

Public RPC

When using a public RPC (Infura, Ankr, default BSC RPC):

• Transactions go to the public mempool

• Validators pick transactions in any order

• No guarantee of same-block inclusion

• Buys typically land within 1–3 blocks of the deploy

• Still effective — tokens are bought at near-initial prices

Private / Builder RPC

When using a private RPC (48Club, Bloxroute):

• Transactions are submitted directly to block builders

• Builders can include all transactions in a single block

• Near-guaranteed same-block inclusion

• Best protection against front-running and sniping

Configuring Private RPC

Set the BSC_PRIVATE_RPC_URL environment variable in the backend:

BSC_PRIVATE_RPC_URL=https://your-48club-or-bloxroute-endpoint

Recommended Providers

Provider	Description
48Club	BSC block builder with bundle support
Bloxroute BDN	MEV protection + transaction bundling
Marlin	BSC relay service

Block Verification

After a bundle executes, the app verifies which blocks each transaction landed in:

• ✅ All same block — all transactions in one block

• ⚠️ Spread across blocks — transactions in nearby blocks

The verification result is shown in the Launch step after completion.

BSC Block Time

BSC produces blocks every ~3 seconds. Even without a private RPC, broadcasting all transactions simultaneously means they'll likely be included in the next few blocks — well before any external snipers can react.