> ## Documentation Index
> Fetch the complete documentation index at: https://bundlezeus.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Atomic Bundles, Explained Simply

> An atomic bundle is a group of transactions that all succeed together or not at all — so your launch happens in one clean shot.

A **bundle** is a group of transactions packed together. **Atomic** means all-or-nothing: **either every transaction in the group works, or none of them do.** There's no in-between.

A "block" is one page in Ethereum's record book, added every few seconds. An atomic bundle guarantees your whole launch lands on the *same* page, in the order you choose.

## Why "all or nothing" is a big deal

Launching the normal way, you send each step on its own: turn on trading, then wallet 1 buys, then wallet 2, and so on. Lots can go wrong:

* A bot sees your "turn on trading" and buys before your wallets do.
* Some of your buys happen later, at a worse price.
* One buy fails, and that wallet gets left out.

An atomic bundle welds everything together, so none of that can happen:

| The normal way                                 | With an atomic bundle                                             |
| ---------------------------------------------- | ----------------------------------------------------------------- |
| Steps happen whenever the network gets to them | Everything happens together, in one block                         |
| Bots can slip in between your steps            | There's no gap for anyone to slip into                            |
| Some buys work, others fail                    | If one fails, the whole thing cancels — you just fix it and retry |
| You can end up half-launched                   | You're either fully launched or not launched at all               |

## "In order" means exactly that

The steps run in the order you set. BundleZeus orders yours like this:

1. Fund your buyer wallets
2. Turn on trading
3. Each wallet buys, one after another
4. Pay the fee

Wallet #1 always gets a slightly better price than wallet #95 — that's just how exchange pricing works (each buy nudges the price up). You can preview this with the [AMM Profit Simulator](/tools/amm-profit-sim).

## The trade-off: you have to get it right

All-or-nothing works both ways. If **any** required step would fail — say your contract blocks one of your buys — the **whole bundle is thrown out** and nothing happens. That's why BundleZeus makes you [do a test run first](/guides/simulate-bundle): it checks your exact launch against the live network and tells you if anything would break, before you spend a thing.

<Tip>
  A cancelled bundle costs you nothing but a little time. A half-finished public launch can cost you the whole launch. Atomic is simply safer — as long as you test first.
</Tip>

## Where this works

* **Ethereum mainnet** — true all-or-nothing bundles, using Flashbots
* **Practice networks (Sepolia, Hoodi, Sandbox)** — all-or-nothing, and free to rehearse on
* **Coming soon** — Base and BNB Chain will use **burst mode** (all transactions fire at once, not truly all-or-nothing); Robinhood Chain will be all-or-nothing like mainnet. See [Supported Networks](/networks).

## Learn more

<Card title="Flashbots & MEV" icon="bolt" href="/concepts/flashbots-mev">
  Where bundles come from, and why the public waiting room is dangerous.
</Card>