> For the complete documentation index, see [llms.txt](https://ai-agent-sdk-docs.crypto.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://ai-agent-sdk-docs.crypto.com/resources/resources-for-developers.md).

# Resources for Developers

## Developer Support Channel 

Developers are welcome to join the [Telegram channel](<https://t.me/cryptocom_agent >) for technical support.

## Cronos Networks and resources

### Explorer API keys

Explorer API keys for Cronos Chains are required to query block chain data, kindly follow the following instruction to obtain the API key for:&#x20;

{% tabs %}
{% tab title="Cronos zkEVM" %}
To get started with the Cronos zkEVM developer API, simply register an account on the [Account Registration page](https://developers.zkevm.cronos.org/register) in Cronos zkEVM developer portal, where you can access a pair of mainnet and testnet API keys on the user dashboard. You can then access the developer API service and use it to retrieve data from the available endpoints.
{% endtab %}

{% tab title="Cronos EVM" %}
Kindly follow the [instructions](https://docs.cronos.org/block-explorers/block-explorer-and-api-keys) to obtain the API key for Cronos EVM
{% endtab %}
{% endtabs %}

### Documentation

For detailed documentation of Cronos Chain, kindly visit:

* Cronos zkEVM - <https://docs-zkevm.cronos.com/>
* Cronos EVM - <https://docs.cronos.com/>

### Cronos zkEVM Mainnet URLs <a href="#cronos-zkevm-mainnet-urls" id="cronos-zkevm-mainnet-urls"></a>

* Chain ID: `388`
* Token: zkCRO ("Cronos zkEVM CRO")
* JSON RPC API (rate limited): [https://mainnet.zkevm.cronos.org](https://mainnet.zkevm.cronos.org/)
* WebSocket (rate limited): `wss://ws.zkevm.cronos.org`
* Blockchain explorer: <https://explorer.zkevm.cronos.org/>
* Gas price: ⚠️ The gas price is currently fixed at 1250 `gwei`
  * This is subject to change and is expected to be dynamic in the next major release to be announced.
* Developer portal: <https://developers.zkevm.cronos.org/>
* Contract verification interface: <https://explorer.zkevm.cronos.org/verifyContract>
* Bridge for ERC-20 tokens (Ethereum <=> Cronos zkEVM): <https://zkevm.cronos.org/bridge>

***

### Cronos zkEVM Sepolia Testnet URLs <a href="#cronos-zkevm-sepolia-testnet-urls" id="cronos-zkevm-sepolia-testnet-urls"></a>

* Chain ID: `240`
* Token: zkTCRO
* JSON RPC API (rate limited): [https://testnet.zkevm.cronos.org](https://testnet.zkevm.cronos.org/)
* WebSocket (rate limited): `wss://ws.testnet.zkevm.cronos.org`
* Blockchain explorer: <https://explorer.zkevm.cronos.org/testnet>
* Gas price: ⚠️ The gas price of is currently fixed at 1250`gwei`
  * This is subject to change and is expected to be dynamic in the next major release to be announced.
* Developer portal: <https://developers.zkevm.cronos.org/>
* Contract verification interface: <https://explorer.zkevm.cronos.org/testnet/verifyContract>
* zkTCRO faucet: <https://zkevm.cronos.org/faucet>
* [Demo project repository](https://github.com/kentimsit/cronos-zkevm-hardhat-boilerplate) for smart contract developers
* Testnet bridge for ERC-20 tokens (zkEVM testnet <=> Ethereum Sepolia): <https://zkevm.cronos.org/bridge/testnet>

***

### Cronos EVM Mainnet URLs <a href="#cronos-zkevm-sepolia-testnet-urls" id="cronos-zkevm-sepolia-testnet-urls"></a>

* Chain ID: `25`
* JSON RPC AP&#x49;**:** [https://evm.cronos.com](https://evm.cronos.com/)
* Block explore&#x72;**:** <https://explorer.cronos.com/>

***

### Cronos EVM Testnet URLs <a href="#cronos-zkevm-sepolia-testnet-urls" id="cronos-zkevm-sepolia-testnet-urls"></a>

* Chain ID: `338`
* JSON RPC API: <https://evm-t3.cronos.com/>
* Block explore&#x72;**:** <https://explorer.cronos.com/testnet>

***