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

# Becoming a validator

> Requirements, responsibilities, and links to the step-by-step guides for joining and operating the Polygon PoS validator set.

<Note title="Transitioning to POL">
  Polygon network is transitioning from MATIC to POL, which will serve as the gas and staking token on Polygon PoS. Use the links below to learn more:

  * [Migrate from MATIC to POL](/pos/concepts/tokens/matic-to-pol)
  * [POL token specs](/pos/concepts/tokens/pol/)
</Note>

Validators maintain the Polygon PoS network by running nodes, staking POL, producing blocks, and participating in consensus. In exchange, they earn staking rewards and transaction fees.

<Note title="Active validator limit">
  The network supports a maximum of 105 active validators at any time. New validators can join the active set only when an existing validator unbonds or is removed for poor performance.

  To apply for a validator slot, submit an application at the [Polygon validators hub](https://polygoncommunity.typeform.com/validatorshub). Submitting an application does not guarantee a slot.
</Note>

## What validators run

To participate as a validator, you must operate two types of nodes:

* **Sentry node**: a Heimdall node and a Bor node, open to all peers on the network. Acts as a public-facing entry point.
* **Validator node**: a Heimdall node and a Bor node, accessible only through its sentry node and closed to the rest of the network.

You also stake POL tokens on the staking contracts deployed on Ethereum mainnet. The minimum stake is 10,000 POL (set by governance proposal PIP-4).

### What each layer does

**Heimdall** (consensus layer):

* Monitors staking contracts on Ethereum mainnet.
* Verifies all state transitions on the Bor chain.
* Submits Bor chain state checkpoints to Ethereum mainnet.

Built on CometBFT and Cosmos SDK. See [GitHub: Heimdall](https://github.com/0xPolygon/heimdall-v2).

**Bor** (execution layer):

* Produces blocks on Polygon PoS.
* Block producers are selected from the validator set by Heimdall based on stake.

Built on Go Ethereum. See [GitHub: Bor](https://github.com/0xPolygon/bor).

## Validator responsibilities

### Node operations

Node operations that happen automatically:

* Block producer selection for each span.
* Block validation on Bor.
* Checkpoint proposal and signing.
* State sync from Ethereum to Bor via the `ack/no-ack` checkpoint mechanism.

### Daily manual operations

* Maintain high uptime. Approximately every 34 minutes, a checkpoint transaction must be signed by every validator. Missed signatures reduce your performance score.
* Check Heimdall and Bor services and processes daily. Prune nodes regularly to reduce disk usage.
* Monitor node health using Grafana dashboards (for example, [Matic-Jagar](https://github.com/vitwit/matic-jagar)) or your own tooling.
* Keep an ETH balance of 0.5 to 1 ETH on your signer address. You need ETH to sign and submit checkpoint transactions on Ethereum mainnet. Running low causes delays in checkpoint submission and downstream finality.

### Delegation

* Accept delegation from the community. Each validator sets their own commission rate. There is no upper limit.
* Communicate commission rates and any rate changes via [Discord](https://discord.com/invite/0xPolygonCommunity) or the [Forum](https://forum.polygon.technology/).

### Communication

* Report issues early via [Discord](https://discord.com/invite/0xPolygonCommunity), [Forum](https://forum.polygon.technology/), or [GitHub](https://github.com/0xPolygon).
* Monitor [Polygon forum announcements](https://forum.polygon.technology/c/announcement/6) for node and validator updates.

## Join the network as a validator

Use one of these guides to set up and run your validator node:

* [Start and run nodes with Ansible](/pos/how-to/validator/validator-ansible/)
* [Start and run nodes with binaries](/pos/how-to/validator/validator-binaries/)
* [Stake as a validator](/pos/how-to/operate-validator-node/next-steps/#stake-tokens)

## Maintain your validator nodes

* [Change the signer address](/pos/how-to/operate-validator-node/change-signer-address/)
* [Change your commission rate](/pos/how-to/operate-validator-node/next-steps/#changing-your-commission-rate)

## Community assistance

* [Discord](https://discord.com/invite/0xPolygonCommunity)
* [Forum](https://forum.polygon.technology/)