Abstract Transaction Fees

The Gas Abstraction endpoint enables fee sponsorship for standard Solana wallet transactions through the Grid paymaster system. This service removes the requirement for users to hold SOL tokens for transaction fees, creating a seamless user experience.

This endpoint is exclusively for standard Solana wallets (keypair-based accounts). For Squads smart accounts with built-in gas abstraction, see Grid v1 Cost Efficiency.

How It Works

The gas abstraction process follows these steps:

Transaction Submission: Send your unsigned, base64-encoded transaction to the endpoint
Fee Calculation: The paymaster computes the required fees in your specified currency (defaults to USDC)
Paymaster Signing: The paymaster adds its signature to sponsor the fees
User Signing: Add the user’s signature to the paymaster-signed transaction
Blockchain Submission: Submit the fully signed transaction to Solana

Implementation Guide

Prepare Your Unsigned Transaction

Create your versioned transaction without signing it:

import {
  VersionedTransaction,
  TransactionMessage,
  SystemProgram,
  PublicKey,
  Connection,
  LAMPORTS_PER_SOL,
} from "@solana/web3.js";

const connection = new Connection("https://api.mainnet-beta.solana.com");

// Create transaction instructions (example: SOL transfer)
const transferInstruction = SystemProgram.transfer({
  fromPubkey: senderPublicKey,
  toPubkey: recipientPublicKey,
  lamports: 0.1 * LAMPORTS_PER_SOL,
});

// Get recent blockhash and build transaction message
const { blockhash } = await connection.getLatestBlockhash();
const messageV0 = new TransactionMessage({
  payerKey: senderPublicKey,
  recentBlockhash: blockhash,
  instructions: [transferInstruction],
}).compileToV0Message();

// Create versioned transaction (unsigned)
const transaction = new VersionedTransaction(messageV0);

// Serialize to base64
const serializedTransaction = Buffer.from(
  transaction.serialize()
).toString("base64");

Submit to Gas Abstraction API

Send your unsigned transaction to the endpoint:

const response = await fetch(
  "https://grid.squads.xyz/api/v0/grid/transactions/eoa/gas-abstraction",
  {
    method: "POST",
    headers: {
      Authorization: "Bearer YOUR_API_KEY",
      "X-Grid-Environment": "production", // or 'sandbox' for devnet
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
      transaction: serializedTransaction,
    }),
  }
);

const result = await response.json();

// Review fee information
console.log(`Fee: ${result.fee.amount_decimal} ${result.fee.currency}`);
console.log(
  `SOL equivalent: ${result.fee.sol_equivalent.amount_decimal} SOL`
);

Sign and Submit to Blockchain

Deserialize the paymaster-signed transaction, add the user’s signature, and submit:

import { VersionedTransaction } from "@solana/web3.js";

// Decode the paymaster-signed transaction
const signedTransactionBuffer = Buffer.from(result.transaction, "base64");
const transaction = VersionedTransaction.deserialize(
  signedTransactionBuffer
);

// Add user's signature
transaction.sign([userKeypair]);

// Submit to blockchain
const signature = await connection.sendTransaction(transaction);
console.log("Transaction signature:", signature);

// Confirm transaction
const confirmation = await connection.confirmTransaction(signature);
console.log(
  "Status:",
  confirmation.value.err ? "Failed" : "Confirmed"
);

Fee Structure

Fee Calculation

The total fee consists of:

Compute Units: Based on transaction complexity and computational requirements
Rent Fees: For account creation or rent-exempt balance requirements
Currency Conversion: Fees quoted in your specified currency (default: USDC)

Billing Details

Sandbox Environment: Devnet transactions are processed but not billed
Production Environment: Mainnet transactions are recorded and billed according to your Grid API agreement
Fee Components: Transaction, priority, and rent fees are included in billing

Custom Identifiers

Use the optional customIdentifier query parameter to group and track related transactions:

const response = await fetch(
  "https://grid.squads.xyz/api/v0/grid/transactions/eoa/gas-abstraction?customIdentifier=user-123-session-abc",
  {
    method: "POST",
    headers: {
      Authorization: "Bearer YOUR_API_KEY",
      "X-Grid-Environment": "production",
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
      transaction: serializedTransaction,
    }),
  }
);

Custom identifiers enable you to:

Group transactions by user, session, or feature
Query fee history by identifier
Track usage patterns and costs per category

Transaction Validation

Transactions must:

Be valid Solana transactions that can be simulated successfully
Use versioned transaction format
Be properly serialized to base64
Not be pre-signed

Error Handling

Common error scenarios:

Invalid Transaction Format

{
  "code": "INVALID_TRANSACTION",
  "message": "tried to parse invalid transaction"
}

Solution: Verify your transaction is properly serialized and base64-encoded.

Invalid Environment Header

{
  "code": "INVALID_ENVIRONMENT",
  "message": "Environment must be either 'sandbox' or 'production'"
}

Solution: Ensure X-Grid-Environment header is set to either sandbox or production.

Service Unavailable

{
  "code": "SERVICE_UNAVAILABLE",
  "message": "The service is temporarily unavailable. Please try again."
}

Solution: Implement retry logic with exponential backoff.

Security Best Practices

API Key Protection: Never expose your Grid API key in client-side code or public repositories
Environment Separation: Use sandbox for testing, production only for live transactions
Transaction Verification: Always validate the returned signed transaction matches your intent
Fee Monitoring: Implement alerts for unexpected fee spikes
Rate Limiting: Implement appropriate rate limiting to avoid overwhelming the API

Authorizations

Authorization

string

header

required

API Key for authentication. Include your Grid API key in the Authorization header.

Headers

X-Grid-Environment

enum<string>

required

The environment you're using. Can be sandbox or production.

Available options:

sandbox,

production

Query Parameters

customIdentifier

string<uuid>

Optional custom identifier for tracking purposes. Used to group and filter transactions.

Body

application/json

transaction

string

required

Base64-encoded unsigned Solana transaction to process for fee abstraction

Example:

"AQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACAAQABBDZi..."

Response

Transaction successfully processed with abstracted fees

transaction

string

required

Base64-encoded signed transaction ready for submission to the blockchain

Example:

"AQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACAAQABBDZi..."

fee

object

required

Detailed fee breakdown for the transaction

Show child attributes

Introduction

API Reference

Abstract Transaction Fees

How It Works

Implementation Guide

Fee Structure

Fee Calculation

Billing Details

Custom Identifiers

Transaction Validation

Error Handling

Invalid Transaction Format

Invalid Environment Header

Service Unavailable

Security Best Practices

Authorizations

Headers

Query Parameters

Body

Response

Introduction

API Reference

​How It Works

​Implementation Guide

​Fee Structure

​Fee Calculation

​Billing Details

​Custom Identifiers

​Transaction Validation

​Error Handling

​Invalid Transaction Format

​Invalid Environment Header

​Service Unavailable

​Security Best Practices

Authorizations

Headers

Query Parameters

Body

Response

How It Works

Implementation Guide

Fee Structure

Fee Calculation

Billing Details

Custom Identifiers

Transaction Validation

Error Handling

Invalid Transaction Format

Invalid Environment Header

Service Unavailable

Security Best Practices