AddGasSponsor

curl --request POST \
  --url https://amoy-relayer.sequence.app/rpc/Relayer/AddGasSponsor \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --header 'X-Access-Key: <api-key>' \
  --data '
{
  "projectId": 123,
  "address": "<string>",
  "name": "<string>",
  "active": true
}
'

import requests

url = "https://amoy-relayer.sequence.app/rpc/Relayer/AddGasSponsor"

payload = {
    "projectId": 123,
    "address": "<string>",
    "name": "<string>",
    "active": True
}
headers = {
    "X-Access-Key": "<api-key>",
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {
    'X-Access-Key': '<api-key>',
    Authorization: 'Bearer <token>',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({projectId: 123, address: '<string>', name: '<string>', active: true})
};

fetch('https://amoy-relayer.sequence.app/rpc/Relayer/AddGasSponsor', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://amoy-relayer.sequence.app/rpc/Relayer/AddGasSponsor",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'projectId' => 123,
    'address' => '<string>',
    'name' => '<string>',
    'active' => true
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json",
    "X-Access-Key: <api-key>"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

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

func main() {

	url := "https://amoy-relayer.sequence.app/rpc/Relayer/AddGasSponsor"

	payload := strings.NewReader("{\n  \"projectId\": 123,\n  \"address\": \"<string>\",\n  \"name\": \"<string>\",\n  \"active\": true\n}")

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

	req.Header.Add("X-Access-Key", "<api-key>")
	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

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

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

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://amoy-relayer.sequence.app/rpc/Relayer/AddGasSponsor")
  .header("X-Access-Key", "<api-key>")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"projectId\": 123,\n  \"address\": \"<string>\",\n  \"name\": \"<string>\",\n  \"active\": true\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://amoy-relayer.sequence.app/rpc/Relayer/AddGasSponsor")

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

request = Net::HTTP::Post.new(url)
request["X-Access-Key"] = '<api-key>'
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"projectId\": 123,\n  \"address\": \"<string>\",\n  \"name\": \"<string>\",\n  \"active\": true\n}"

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

{
  "status": true,
  "gasSponsor": {
    "id": 123,
    "gasTankId": 123,
    "projectId": 123,
    "chainId": 123,
    "address": "<string>",
    "name": "<string>",
    "active": true,
    "updatedAt": "<string>",
    "createdAt": "<string>",
    "deletedAt": "<string>"
  }
}

{
  "error": "WebrpcEndpoint",
  "code": 0,
  "msg": "endpoint error",
  "status": 400,
  "cause": "<string>"
}

{
  "error": "WebrpcBadResponse",
  "code": -5,
  "msg": "bad response",
  "status": 500,
  "cause": "<string>"
}

POST

rpc

Relayer

AddGasSponsor

curl --request POST \
  --url https://amoy-relayer.sequence.app/rpc/Relayer/AddGasSponsor \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --header 'X-Access-Key: <api-key>' \
  --data '
{
  "projectId": 123,
  "address": "<string>",
  "name": "<string>",
  "active": true
}
'

import requests

url = "https://amoy-relayer.sequence.app/rpc/Relayer/AddGasSponsor"

payload = {
    "projectId": 123,
    "address": "<string>",
    "name": "<string>",
    "active": True
}
headers = {
    "X-Access-Key": "<api-key>",
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {
    'X-Access-Key': '<api-key>',
    Authorization: 'Bearer <token>',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({projectId: 123, address: '<string>', name: '<string>', active: true})
};

fetch('https://amoy-relayer.sequence.app/rpc/Relayer/AddGasSponsor', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://amoy-relayer.sequence.app/rpc/Relayer/AddGasSponsor",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'projectId' => 123,
    'address' => '<string>',
    'name' => '<string>',
    'active' => true
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json",
    "X-Access-Key: <api-key>"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

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

func main() {

	url := "https://amoy-relayer.sequence.app/rpc/Relayer/AddGasSponsor"

	payload := strings.NewReader("{\n  \"projectId\": 123,\n  \"address\": \"<string>\",\n  \"name\": \"<string>\",\n  \"active\": true\n}")

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

	req.Header.Add("X-Access-Key", "<api-key>")
	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

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

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

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://amoy-relayer.sequence.app/rpc/Relayer/AddGasSponsor")
  .header("X-Access-Key", "<api-key>")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"projectId\": 123,\n  \"address\": \"<string>\",\n  \"name\": \"<string>\",\n  \"active\": true\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://amoy-relayer.sequence.app/rpc/Relayer/AddGasSponsor")

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

request = Net::HTTP::Post.new(url)
request["X-Access-Key"] = '<api-key>'
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"projectId\": 123,\n  \"address\": \"<string>\",\n  \"name\": \"<string>\",\n  \"active\": true\n}"

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

{
  "status": true,
  "gasSponsor": {
    "id": 123,
    "gasTankId": 123,
    "projectId": 123,
    "chainId": 123,
    "address": "<string>",
    "name": "<string>",
    "active": true,
    "updatedAt": "<string>",
    "createdAt": "<string>",
    "deletedAt": "<string>"
  }
}

{
  "error": "WebrpcEndpoint",
  "code": 0,
  "msg": "endpoint error",
  "status": 400,
  "cause": "<string>"
}

{
  "error": "WebrpcBadResponse",
  "code": -5,
  "msg": "bad response",
  "status": 500,
  "cause": "<string>"
}

Overview

AddGasSponsor registers a new gas sponsor for your project on the Relayer’s chain. Once a sponsor is active, the Transactions API relays matching transactions from your users without charging them gas — the cost is drawn from your project’s gas tank balance. You can sponsor:

A wallet address — any transaction sent from that wallet on this chain is sponsored.
A contract address — any user’s interaction with that contract on this chain is sponsored.
An arbitrary address — native-token transfers to that address are sponsored.

The same feature is available in Sequence Builder under Gas Sponsorship — the API is what powers it, and is the right choice when you need to manage sponsors programmatically (e.g. onboarding a new user cohort from your backend).

Authentication

AddGasSponsor is a privileged write endpoint. Every request must include both headers:

Header	Value	Where to find it
`X-Access-Key`	Public API Access Key	Sequence Builder → Settings → API Keys → Public API Access Keys
`Authorization`	`Bearer <admin-api-secret-key>`	Sequence Builder → Settings → API Keys → Admin API Secret Keys

Sending only the access key returns 403 PermissionDenied. Sending only the secret key returns 401 AccessKeyNotFound. Both keys must be present.

The Admin API Secret Key is a privileged JWT credential. Only use it from a trusted backend — never expose it in a browser, mobile app, or public repository.

If either section on the API Keys page is empty (You have no API Keys), create the missing key with + Add Public API Access Key or + Add Admin API Secret Key before calling this endpoint.

Endpoint URL

AddGasSponsor is exposed on each network’s Relayer host. Use the host matching the chain you want to sponsor on — for example:

Base mainnet: https://base-relayer.sequence.app/rpc/Relayer/AddGasSponsor
Polygon mainnet: https://polygon-relayer.sequence.app/rpc/Relayer/AddGasSponsor
Arbitrum mainnet: https://arbitrum-relayer.sequence.app/rpc/Relayer/AddGasSponsor

The full list of Relayer hosts is on the Transactions API overview.

Example request

cURL

curl -X POST https://base-relayer.sequence.app/rpc/Relayer/AddGasSponsor \
  -H "Content-Type: application/json" \
  -H "X-Access-Key: $SEQUENCE_ACCESS_KEY" \
  -H "Authorization: Bearer $SEQUENCE_ADMIN_SECRET_KEY" \
  -d '{
    "projectId": 43551,
    "address": "0xYourContractOrWalletAddress",
    "name": "Free mint contract",
    "active": true
  }'

Common errors

Status	`error`	Meaning
`401`	`AccessKeyNotFound`	The `X-Access-Key` header is missing or does not match a Public API Access Key on this project.
`403`	`PermissionDenied`	The request is missing the Admin API Secret Key, or the key does not have write permission for this project.
`400`	`InvalidArgument`	`projectId` or `address` is missing or malformed.

Authorizations

X-Access-Key

string

header

required

Public project access key for authenticating requests obtained on Sequence Builder. Example Test Key: AQAAAAAAAEGvyZiWA9FMslYeG_yayXaHnSI

Authorization

string

header

required

Secret JWT token for authenticating requests obtained from Sequence Builder - should not be exposed publicly.

Body

application/json

projectId

number

address

string

name

string

active

boolean

Response

status

boolean

Show child attributes

Indexer

Indexer Gateway

Analytics

Metadata

Infrastructure

Builder

Marketplace

Transactions

Blockchain RPC

AddGasSponsor

Overview

Authentication

Endpoint URL

Example request

Common errors

Authorizations

Body

Response

​Overview

​Authentication

​Endpoint URL

​Example request

​Common errors

Authorizations

Body

Response

Overview

Authentication

Endpoint URL

Example request

Common errors