> For the complete documentation index, see [llms.txt](https://docs.fiammalabs.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.fiammalabs.io/our-product-suite/pragmatically-trustless-bitvm-bitcoin-bridge/user-guides/mainnet/fiamma-challenger.md).

# Fiamma Challenger

### Introduction

* Fiamma Challenger is a permissionless role that allows anyone to help monitor bridge operators.
* A challenger can initiate a challenge if the operator acts maliciously, and will be rewarded upon a valid submission.
* You need to have a Bitcoin wallet, and stake 0.0001 BTC to become a challenger.

### Get started

1. Connect your Bitcoin wallet to get started.

<figure><img src="/files/LMnK6bdAIr2n6AjSeWpk" alt=""><figcaption></figcaption></figure>

2. Stake 0.0001 BTC as security deposit to become a challenger. (If a challenger is found to act maliciously, the security deposit will be slashed to punish such behavior.) Wait for several minutes for the staking to be processed.

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3. Once the staking completes, click the "Verify" button to start your challenger role. The challenger app will automatically verify proofs from transactions.

<figure><img src="/files/sbd4dlTVpGk4b1SjEBSN" alt=""><figcaption></figcaption></figure>

### Submit a Challenge

If an operator acted maliciously (e.g., tried to steal user's funds by submitting fake proofs), the bridge will send out challenge tasks to challengers. You will see the challenge task pop up in the Total Challenged section:

* Note: you'll need to prepare for 0.001 BTC to submit a challenge.

<figure><img src="/files/RprVYHwvujAGhcAED0Gk" alt=""><figcaption></figcaption></figure>

1. Click the red pop up button to enter Challenge page. Here you will see all challenges listed on the left.

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2. Click one of the challenges to see the details. Each challenge task has two stages. You may be assigned to any one of them, while the other one can be completed by different challengers. Click "Submit Challenge" to submit this challenge to the bridge.

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Once successfully submitted, you will see a Submit Challenge Success notification on the top right.

<figure><img src="/files/XHNe3FwPXDtfj4RvtZVP" alt=""><figcaption></figcaption></figure>

Note: Since the same task is sent to all challengers, **only** the first valid submission will count as successful. If another challenger submits before you, your submission will not be accepted.

<figure><img src="/files/UfY85mAbYPc7sZcBzfdF" alt=""><figcaption></figcaption></figure>