Base Sepolia Denim activated — October 21, 2026

Denim activated on Base Sepolia on October 21, 2026, replacing Flashblocks with canonical 200ms blocks. Flashblocks subscriptions and the "pending" block tag no longer provide preconfirmation data on Sepolia. Use canonical blocks and state instead. Base Mainnet continues to use Flashblocks until its own Denim activation, which is targeting November 2026.

See the Denim migration steps.

Parameters

transaction

object

REQUIRED

The transaction call object which contains the following fields:

from

string

The address from which the transaction is sent

to

string

REQUIRED

The address to which the transaction is addressed

gas

integer

The integer of gas provided for the transaction execution

gasPrice

integer

The integer of gasPrice used for each paid gas encoded as hexadecimal

value

integer

The integer of value sent with this transaction encoded as hexadecimal

data

string

The hash of the method signature and encoded parameters. For more information, see the Contract ABI description in the Solidity documentation

blockNumber/tag

string

REQUIRED

The block number in hexadecimal format or the string latest, earliest, pending, safe or finalized (safe and finalized tags are only supported on Ethereum, Gnosis, Arbitrum, Arbitrum Nova and Avalanche C-chain), see the default block parameter description in the official Ethereum documentation

Object

object

The State Override Set option allows you to change the state of a contract before executing the call, which means you can modify the values of variables stored in the contract, such as balances and approvals for that call without actually modifying the contract. Each address maps to an object containing:

balance

string

The fake balance to set for the account before executing the call

nonce

string

The fake nonce to set for the account before executing the call

code

string

The fake EVM bytecode to inject into the account before executing the call

state

object

The fake key-value mapping to override all slots in the account storage before executing the call

stateDiff

integer

The fake key-value mapping to override individual slots in the account storage before executing the call

Returns

data

The return value of the executed contract method

Request

1
curl -X POST "https://docs-demo.base-mainnet.quiknode.pro/" \
2
  -H "Content-Type: application/json" \
3
  -d '{
4
  "jsonrpc": "2.0",
5
  "method": "eth_call",
6
  "params": [
7
    {
8
      "to": "0x0fd43c8fabe26d70dfa4c8b6fa680db39f147460",
9
      "data": "0x919840ad"
10
    },
11
    "latest"
12
  ],
13
  "id": 1
14
}'

1
curl -X POST "https://docs-demo.base-mainnet.quiknode.pro/" \
2
  -H "Content-Type: application/json" \
3
  -d '{
4
  "jsonrpc": "2.0",
5
  "method": "eth_call",
6
  "params": [
7
    {
8
      "to": "0x0fd43c8fabe26d70dfa4c8b6fa680db39f147460",
9
      "data": "0x919840ad"
10
    },
11
    "latest"
12
  ],
13
  "id": 1
14
}'

1
import { ethers } from "ethers";
2

3
async function main() {
4
    const provider = new ethers.JsonRpcProvider("https://docs-demo.base-mainnet.quiknode.pro/");
5
    const response = await provider.send("eth_call", [
6
    {
7
        "to": "0x0fd43c8fabe26d70dfa4c8b6fa680db39f147460",
8
        "data": "0x919840ad"
9
    },
10
    "latest"
11
]);
12
    console.log(response);
13
}
14

15
main();

1
import { ethers } from "ethers";
2

3
async function main() {
4
    const provider = new ethers.JsonRpcProvider("https://docs-demo.base-mainnet.quiknode.pro/");
5
    const response = await provider.send("eth_call", [
6
    {
7
        "to": "0x0fd43c8fabe26d70dfa4c8b6fa680db39f147460",
8
        "data": "0x919840ad"
9
    },
10
    "latest"
11
]);
12
    console.log(response);
13
}
14

15
main();

1
from web3 import Web3, HTTPProvider
2
w3 = Web3(HTTPProvider('https://docs-demo.base-mainnet.quiknode.pro/'))
3
abi = '[{"constant":True,"inputs":[{"internalType":"address","name":"","type":"address"}],"name":"balanceOf","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"payable":False,"stateMutability":"view","type":"function"}]'
4
myContract = w3.eth.contract(address="0x0fd43c8fabe26d70dfa4c8b6fa680db39f147460", abi=abi)
5
response = myContract.functions.balanceOf("0x0000000000000000000000000000000000000000").call()
6
print(response)

1
from web3 import Web3, HTTPProvider
2
w3 = Web3(HTTPProvider('https://docs-demo.base-mainnet.quiknode.pro/'))
3
abi = '[{"constant":True,"inputs":[{"internalType":"address","name":"","type":"address"}],"name":"balanceOf","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"payable":False,"stateMutability":"view","type":"function"}]'
4
myContract = w3.eth.contract(address="0x0fd43c8fabe26d70dfa4c8b6fa680db39f147460", abi=abi)
5
response = myContract.functions.balanceOf("0x0000000000000000000000000000000000000000").call()
6
print(response)

1
import { createPublicClient, http } from 'viem'
2

3
async function main() {
4
    const client = createPublicClient({
5
        transport: http('https://docs-demo.base-mainnet.quiknode.pro/')
6
    })
7

8
    const result = await client.request({
9
        method: 'eth_call',
10
        params: [
11
          {
12
            "to": "0x0fd43c8fabe26d70dfa4c8b6fa680db39f147460",
13
            "data": "0x919840ad"
14
          },
15
          "latest"
16
        ]
17
    })
18

19
    console.log(result)
20
}
21

22
main()

1
import { createPublicClient, http } from 'viem'
2

3
async function main() {
4
    const client = createPublicClient({
5
        transport: http('https://docs-demo.base-mainnet.quiknode.pro/')
6
    })
7

8
    const result = await client.request({
9
        method: 'eth_call',
10
        params: [
11
          {
12
            "to": "0x0fd43c8fabe26d70dfa4c8b6fa680db39f147460",
13
            "data": "0x919840ad"
14
          },
15
          "latest"
16
        ]
17
    })
18

19
    console.log(result)
20
}
21

22
main()

1
import { QuicknodeSdk } from '@quicknode/sdk'
2

3
const qn = new QuicknodeSdk({})
4

5
const result = await qn.rpc.call(
6
  'eth_call',
7
  [
8
  {
9
    "to": "0x0fd43c8fabe26d70dfa4c8b6fa680db39f147460",
10
    "data": "0x919840ad"
11
  },
12
  "latest"
13
],
14
  undefined,
15
  'https://docs-demo.base-mainnet.quiknode.pro/'
16
)
17

18
console.log(result)

1
import { QuicknodeSdk } from '@quicknode/sdk'
2

3
const qn = new QuicknodeSdk({})
4

5
const result = await qn.rpc.call(
6
  'eth_call',
7
  [
8
  {
9
    "to": "0x0fd43c8fabe26d70dfa4c8b6fa680db39f147460",
10
    "data": "0x919840ad"
11
  },
12
  "latest"
13
],
14
  undefined,
15
  'https://docs-demo.base-mainnet.quiknode.pro/'
16
)
17

18
console.log(result)

1
import asyncio
2
from quicknode_sdk import QuicknodeSdk, SdkFullConfig
3

4
async def main():
5
    qn = QuicknodeSdk(SdkFullConfig(api_key=None))
6
    result = await qn.rpc.call(
7
        "eth_call",
8
        [
9
            {
10
                "to": "0x0fd43c8fabe26d70dfa4c8b6fa680db39f147460",
11
                "data": "0x919840ad"
12
            },
13
            "latest"
14
        ],
15
        endpoint_url="https://docs-demo.base-mainnet.quiknode.pro/",
16
    )
17
    print(result)
18

19
asyncio.run(main())

1
import asyncio
2
from quicknode_sdk import QuicknodeSdk, SdkFullConfig
3

4
async def main():
5
    qn = QuicknodeSdk(SdkFullConfig(api_key=None))
6
    result = await qn.rpc.call(
7
        "eth_call",
8
        [
9
            {
10
                "to": "0x0fd43c8fabe26d70dfa4c8b6fa680db39f147460",
11
                "data": "0x919840ad"
12
            },
13
            "latest"
14
        ],
15
        endpoint_url="https://docs-demo.base-mainnet.quiknode.pro/",
16
    )
17
    print(result)
18

19
asyncio.run(main())

1
require "quicknode_sdk"
2

3
qn = QuicknodeSdk::SDK.from_config(api_key: nil)
4

5
result = qn.rpc.call(
6
  method: "eth_call",
7
  params: [
8
    {
9
      "to" => "0x0fd43c8fabe26d70dfa4c8b6fa680db39f147460",
10
      "data" => "0x919840ad"
11
    },
12
    "latest"
13
  ],
14
  endpoint_url: "https://docs-demo.base-mainnet.quiknode.pro/"
15
)
16

17
puts result

1
require "quicknode_sdk"
2

3
qn = QuicknodeSdk::SDK.from_config(api_key: nil)
4

5
result = qn.rpc.call(
6
  method: "eth_call",
7
  params: [
8
    {
9
      "to" => "0x0fd43c8fabe26d70dfa4c8b6fa680db39f147460",
10
      "data" => "0x919840ad"
11
    },
12
    "latest"
13
  ],
14
  endpoint_url: "https://docs-demo.base-mainnet.quiknode.pro/"
15
)
16

17
puts result

1
use quicknode_sdk::{QuicknodeSdk, SdkFullConfig};
2

3
#[tokio::main]
4
async fn main() -> Result<(), Box<dyn std::error::Error>> {
5
    let qn = QuicknodeSdk::new(&SdkFullConfig::keyless())?;
6
    let result = qn
7
        .rpc
8
        .call(
9
            "eth_call",
10
            Some(serde_json::json!([
11
    {
12
        "to": "0x0fd43c8fabe26d70dfa4c8b6fa680db39f147460",
13
        "data": "0x919840ad"
14
    },
15
    "latest"
16
])),
17
            None,
18
            Some("https://docs-demo.base-mainnet.quiknode.pro/".into()),
19
        )
20
        .await?;
21

22
    println!("{result}");
23
    Ok(())
24
}

1
use quicknode_sdk::{QuicknodeSdk, SdkFullConfig};
2

3
#[tokio::main]
4
async fn main() -> Result<(), Box<dyn std::error::Error>> {
5
    let qn = QuicknodeSdk::new(&SdkFullConfig::keyless())?;
6
    let result = qn
7
        .rpc
8
        .call(
9
            "eth_call",
10
            Some(serde_json::json!([
11
    {
12
        "to": "0x0fd43c8fabe26d70dfa4c8b6fa680db39f147460",
13
        "data": "0x919840ad"
14
    },
15
    "latest"
16
])),
17
            None,
18
            Some("https://docs-demo.base-mainnet.quiknode.pro/".into()),
19
        )
20
        .await?;
21

22
    println!("{result}");
23
    Ok(())
24
}

1
const body = {
2
    jsonrpc: '2.0',
3
    method: 'eth_call',
4
    params: [{"to":"0x0fd43c8fabe26d70dfa4c8b6fa680db39f147460","data":"0x919840ad"},"latest"],
5
    id: 1
6
}
7

8
async function main() {
9
    const response = await fetch('https://docs-demo.base-mainnet.quiknode.pro/', {
10
        method: 'POST',
11
        headers: {'Content-Type': 'application/json'},
12
        body: JSON.stringify(body)
13
    })
14
    const data = await response.json()
15
    console.log(data)
16
}
17

18
main()

1
const body = {
2
    jsonrpc: '2.0',
3
    method: 'eth_call',
4
    params: [{"to":"0x0fd43c8fabe26d70dfa4c8b6fa680db39f147460","data":"0x919840ad"},"latest"],
5
    id: 1
6
}
7

8
async function main() {
9
    const response = await fetch('https://docs-demo.base-mainnet.quiknode.pro/', {
10
        method: 'POST',
11
        headers: {'Content-Type': 'application/json'},
12
        body: JSON.stringify(body)
13
    })
14
    const data = await response.json()
15
    console.log(data)
16
}
17

18
main()

1
import requests
2
import json
3

4
url = "https://docs-demo.base-mainnet.quiknode.pro/"
5

6
payload = json.dumps({
7
  "jsonrpc": "2.0",
8
  "method": "eth_call",
9
  "params": [
10
    {
11
      "to": "0x0fd43c8fabe26d70dfa4c8b6fa680db39f147460",
12
      "data": "0x919840ad"
13
    },
14
    "latest"
15
  ],
16
  "id": 1
17
})
18
headers = {
19
  'Content-Type': 'application/json'
20
}
21

22
response = requests.request("POST", url, headers=headers, data=payload)
23

24
print(response.text)

1
import requests
2
import json
3

4
url = "https://docs-demo.base-mainnet.quiknode.pro/"
5

6
payload = json.dumps({
7
  "jsonrpc": "2.0",
8
  "method": "eth_call",
9
  "params": [
10
    {
11
      "to": "0x0fd43c8fabe26d70dfa4c8b6fa680db39f147460",
12
      "data": "0x919840ad"
13
    },
14
    "latest"
15
  ],
16
  "id": 1
17
})
18
headers = {
19
  'Content-Type': 'application/json'
20
}
21

22
response = requests.request("POST", url, headers=headers, data=payload)
23

24
print(response.text)

1
require "uri"
2
require "json"
3
require "net/http"
4

5
uri = URI("https://docs-demo.base-mainnet.quiknode.pro/")
6

7
payload = {
8
  jsonrpc: "2.0",
9
  id: 1,
10
  method: "eth_call",
11
  params: [{"to":"0x0fd43c8fabe26d70dfa4c8b6fa680db39f147460","data":"0x919840ad"},"latest"]
12
}
13

14
request = Net::HTTP::Post.new(uri)
15
request["Content-Type"] = "application/json"
16
request.body = JSON.generate(payload)
17

18
response = Net::HTTP.start(uri.host, uri.port, use_ssl: true) do |http|
19
  http.request(request)
20
end
21

22
puts response.body

1
require "uri"
2
require "json"
3
require "net/http"
4

5
uri = URI("https://docs-demo.base-mainnet.quiknode.pro/")
6

7
payload = {
8
  jsonrpc: "2.0",
9
  id: 1,
10
  method: "eth_call",
11
  params: [{"to":"0x0fd43c8fabe26d70dfa4c8b6fa680db39f147460","data":"0x919840ad"},"latest"]
12
}
13

14
request = Net::HTTP::Post.new(uri)
15
request["Content-Type"] = "application/json"
16
request.body = JSON.generate(payload)
17

18
response = Net::HTTP.start(uri.host, uri.port, use_ssl: true) do |http|
19
  http.request(request)
20
end
21

22
puts response.body

Response

1
{
2
  "jsonrpc": "2.0",
3
  "id": 1,
4
  "result": "0x"
5
}

1
{
2
  "jsonrpc": "2.0",
3
  "id": 1,
4
  "result": "0x"
5
}

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