> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs.galleon8.com/api-reference/node-api/ethereum/api-endpoints/standard-api/eth-estimate-gas/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.galleon8.com/_mcp/server.

# eth_estimateGas

POST https://node-api-docs-proxy.galleon8.workers.dev
Content-Type: application/json

Generates and returns an estimate of how much gas is necessary to allow the transaction to complete.

Reference: https://docs.galleon8.com/api-reference/node-api/ethereum/api-endpoints/standard-api/eth-estimate-gas

## Request

### Body (application/json)

This endpoint expects an object.

- `transaction` (TransactionRequest, required) — Transaction request to estimate.
- `block` (any, optional) — Optional block number or tag used as the execution context.

## Response

### 200

Estimated gas amount encoded as a hexadecimal quantity.

- `string`

## Types

### TransactionRequest

Transaction request object used for gas estimation.

- `from` (string, optional) — 20-byte EVM address.
- `to` (string, optional, nullable) — 20-byte EVM address.
- `gas` (string, optional) — Hex-encoded integer quantity.
- `gasPrice` (string, optional) — Hex-encoded integer quantity.
- `value` (string, optional) — Hex-encoded integer quantity.
- `data` (string, optional) — Hex-encoded byte data.
- `input` (string, optional) — Hex-encoded byte data.
- `maxFeePerGas` (string, optional) — Hex-encoded integer quantity.
- `maxPriorityFeePerGas` (string, optional) — Hex-encoded integer quantity.
- `accessList` (list of AccessListItems, optional) — EIP-2930 access list.

### AccessListItems

- `address` (string, required) — 20-byte EVM address.
- `storageKeys` (list of string, required)

## Examples

**Request**

```json
[
  {
    "from": "0x742d35Cc6634C0532925a3b844Bc454e4438f44e",
    "to": "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48",
    "value": "0x0",
    "data": "0xa9059cbb000000000000000000000000742d35cc6634c0532925a3b844bc454e4438f44e0000000000000000000000000000000000000000000000000000000005f5e100"
  },
  "latest"
]
```

**Response**

```json
{
  "jsonrpc": "2.0",
  "id": "1",
  "result": "0xc350"
}
```

**SDK Code**

```python
import requests

url = "https://node-api-docs-proxy.galleon8.workers.dev/"

payload = [
    {
        "from": "0x742d35Cc6634C0532925a3b844Bc454e4438f44e",
        "to": "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48",
        "value": "0x0",
        "data": "0xa9059cbb000000000000000000000000742d35cc6634c0532925a3b844bc454e4438f44e0000000000000000000000000000000000000000000000000000000005f5e100"
    },
    "latest"
]
headers = {"Content-Type": "application/json"}

response = requests.post(url, json=payload, headers=headers)

print(response.json())
```

```javascript
const url = 'https://node-api-docs-proxy.galleon8.workers.dev/';
const options = {
  method: 'POST',
  headers: {'Content-Type': 'application/json'},
  body: '[{"from":"0x742d35Cc6634C0532925a3b844Bc454e4438f44e","to":"0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48","value":"0x0","data":"0xa9059cbb000000000000000000000000742d35cc6634c0532925a3b844bc454e4438f44e0000000000000000000000000000000000000000000000000000000005f5e100"},"latest"]'
};

try {
  const response = await fetch(url, options);
  const data = await response.json();
  console.log(data);
} catch (error) {
  console.error(error);
}
```

```go
package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://node-api-docs-proxy.galleon8.workers.dev/"

	payload := strings.NewReader("[\n  {\n    \"from\": \"0x742d35Cc6634C0532925a3b844Bc454e4438f44e\",\n    \"to\": \"0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48\",\n    \"value\": \"0x0\",\n    \"data\": \"0xa9059cbb000000000000000000000000742d35cc6634c0532925a3b844bc454e4438f44e0000000000000000000000000000000000000000000000000000000005f5e100\"\n  },\n  \"latest\"\n]")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(res)
	fmt.Println(string(body))

}
```

```ruby
require 'uri'
require 'net/http'

url = URI("https://node-api-docs-proxy.galleon8.workers.dev/")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Content-Type"] = 'application/json'
request.body = "[\n  {\n    \"from\": \"0x742d35Cc6634C0532925a3b844Bc454e4438f44e\",\n    \"to\": \"0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48\",\n    \"value\": \"0x0\",\n    \"data\": \"0xa9059cbb000000000000000000000000742d35cc6634c0532925a3b844bc454e4438f44e0000000000000000000000000000000000000000000000000000000005f5e100\"\n  },\n  \"latest\"\n]"

response = http.request(request)
puts response.read_body
```

```java
import com.mashape.unirest.http.HttpResponse;
import com.mashape.unirest.http.Unirest;

HttpResponse<String> response = Unirest.post("https://node-api-docs-proxy.galleon8.workers.dev/")
  .header("Content-Type", "application/json")
  .body("[\n  {\n    \"from\": \"0x742d35Cc6634C0532925a3b844Bc454e4438f44e\",\n    \"to\": \"0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48\",\n    \"value\": \"0x0\",\n    \"data\": \"0xa9059cbb000000000000000000000000742d35cc6634c0532925a3b844bc454e4438f44e0000000000000000000000000000000000000000000000000000000005f5e100\"\n  },\n  \"latest\"\n]")
  .asString();
```

```php
<?php
require_once('vendor/autoload.php');

$client = new \GuzzleHttp\Client();

$response = $client->request('POST', 'https://node-api-docs-proxy.galleon8.workers.dev/', [
  'body' => '[
  {
    "from": "0x742d35Cc6634C0532925a3b844Bc454e4438f44e",
    "to": "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48",
    "value": "0x0",
    "data": "0xa9059cbb000000000000000000000000742d35cc6634c0532925a3b844bc454e4438f44e0000000000000000000000000000000000000000000000000000000005f5e100"
  },
  "latest"
]',
  'headers' => [
    'Content-Type' => 'application/json',
  ],
]);

echo $response->getBody();
```

```csharp
using RestSharp;

var client = new RestClient("https://node-api-docs-proxy.galleon8.workers.dev/");
var request = new RestRequest(Method.POST);
request.AddHeader("Content-Type", "application/json");
request.AddParameter("application/json", "[\n  {\n    \"from\": \"0x742d35Cc6634C0532925a3b844Bc454e4438f44e\",\n    \"to\": \"0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48\",\n    \"value\": \"0x0\",\n    \"data\": \"0xa9059cbb000000000000000000000000742d35cc6634c0532925a3b844bc454e4438f44e0000000000000000000000000000000000000000000000000000000005f5e100\"\n  },\n  \"latest\"\n]", ParameterType.RequestBody);
IRestResponse response = client.Execute(request);
```

```swift
import Foundation

let headers = ["Content-Type": "application/json"]
let parameters = [
  [
    "from": "0x742d35Cc6634C0532925a3b844Bc454e4438f44e",
    "to": "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48",
    "value": "0x0",
    "data": "0xa9059cbb000000000000000000000000742d35cc6634c0532925a3b844bc454e4438f44e0000000000000000000000000000000000000000000000000000000005f5e100"
  ],
  "latest"
] as [String : Any]

let postData = JSONSerialization.data(withJSONObject: parameters, options: [])

let request = NSMutableURLRequest(url: NSURL(string: "https://node-api-docs-proxy.galleon8.workers.dev/")! as URL,
                                        cachePolicy: .useProtocolCachePolicy,
                                    timeoutInterval: 10.0)
request.httpMethod = "POST"
request.allHTTPHeaderFields = headers
request.httpBody = postData as Data

let session = URLSession.shared
let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
  if (error != nil) {
    print(error as Any)
  } else {
    let httpResponse = response as? HTTPURLResponse
    print(httpResponse)
  }
})

dataTask.resume()
```