Detect Buy/Sell Transaction Type on Pumpfun

Learn how to detect Pumpfun transaction type using Solana Yellowstone geyser gRPC and IDL-based parsers.

Tracking buy and sell events on Pump.Fun is crucial for trading bots and market analysis. This guide details how to utilize Solana's Yellowstone gRPC stream to efficiently capture and parse real-time transaction data, enabling instant detection of token swaps and providing a significant edge in the fast-paced Solana memecoin market.

The complete source code for this project is available on GitHub.

• TypeScript

• Rust

Please feel free to clone the repository and try it out. Additionally, you will find other relevant and useful code examples related to gRPC and streaming here.

Step-by-Step Breakdown

This project consists of two key components:

1. Streaming Pump.fun Transactions via Yellowstone gRPC

2. Parsing the Received transactions along with events

3. Identifying Buy / Sell transactions based on the Pump Events

Streaming Transactions Using gRPC

The first step involves initializing the Solana Yellowstone Client. You can get Solana Yellowstone gRPC access from the Shyft Dashboard. Please check out our gRPC Authentication Docs for more details.

Initializing the Client

Once you have the authentication details, you can initialize the client in the following manner,

TypeScript

import Client from "@triton-one/yellowstone-grpc";

const client = new Client(
  "YOUR-GRPC-ENDPOINT", //yellowstone grpc url
  "GRPC-ACCESS-TOKEN", //authentication token
  undefined
);

Rust

You can use any Yellowstone gRPC endpoint with this client. An access token is optional, as some gRPC services don't require authentication.

The Rust client supports several additional options, as demonstrated in the example above. Most of these options are also available for the TS client, where they are passed as the third argument to the Client constructor.

Specifying what data to stream from gRPC

To specify what on-chain data, we send a SubscribeRequest over the existing Solana Yellowstone gRPC client. These Request allows you to filter for specific accounts, transactions, slots, or other Solana on-chain events, giving you full control over the data you receive. You can find out more about Subscribe Requests here.

Subscribe Requests specify what data to stream by the means of filters. When you want to stream transactions, you use a transaction filter. Inside this filter, you tell it which program's transactions you're interested in by providing its "program ID" in the "account" field. The example below demonstrates how to initiate a gRPC stream by sending a SubscribeRequest using a standard gRPC client:

TypeScript

const req: SubscribeRequest = {
  accounts: {},
  slots: {},
  transactions: {
    pumpFun: {
      vote: false,
      failed: false,
      signature: undefined,
      accountInclude: ["6EF8rrecthR5Dkzon8Nwu78hRvfCKubJ14M5uBEwF6P"],
      //for our usecase we only need to listen to transaction belonging to one program, so we have added one address
      accountExclude: [],
      accountRequired: [],
    },
  },
  transactionsStatus: {},
  entry: {},
  blocks: {},
  blocksMeta: {},
  accountsDataSlice: [],
  ping: undefined,
  commitment: CommitmentLevel.CONFIRMED,
};

Rust

Once established, the stream will begin sending data directly to your application. You have the flexibility to modify your subscription on the fly, allowing you to change the data specifications you receive without stopping your stream. For more details on reconnecting and re-starting the stream from a specific slot, or closing your gRPC connection, you can find additional information in our documentation.

Parsing the received transaction

Once a raw Solana transaction is received via the Yellowstone gRPC stream, it must be parsed to extract meaningful, human-readable data. For JavaScript/TypeScript applications, we use Shyft's IDL-based transaction parser, which decodes the transactions received from the gRPC into structured data based on the respective program's IDL. On Rust however, we use a interface generated by solores to parse the transaction instruction.

TypeScript

import { SolanaParser } from "@shyft-to/solana-transaction-parser";

const PUMP_FUN_IX_PARSER = new SolanaParser([]);
//initializing the parser

PUMP_FUN_IX_PARSER.addParserFromIdl(
  "6EF8rrecthR5Dkzon8Nwu78hRvfCKubJ14M5uBEwF6P",
  pumpFunAmmIdl as Idl
);

const PUMP_FUN_EVENT_PARSER = new SolanaEventParser([], console);
PUMP_FUN_EVENT_PARSER.addParserFromIdl(
  "6EF8rrecthR5Dkzon8Nwu78hRvfCKubJ14M5uBEwF6P",
  pumpFunAmmIdl as Idl
);
//adding pump.fun idl for parsing pumpfun transactions

function decodePumpFunTxn(tx: VersionedTransactionResponse) {
  if (tx.meta?.err) return;
  try{
    const paredIxs = PUMP_FUN_IX_PARSER.parseTransactionData(
      tx.transaction.message,
      tx.meta.loadedAddresses,
    ); //parsing transaction
  
    const pumpFunIxs = paredIxs.filter((ix) =>
      ix.programId.equals(PUMP_FUN_PROGRAM_ID) || ix.programId.equals(new PublicKey("TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA")),
    );
  
    const parsedInnerIxs = PUMP_FUN_IX_PARSER.parseTransactionWithInnerInstructions(tx);
  
    const pumpfun_amm_inner_ixs = parsedInnerIxs.filter((ix) =>
      ix.programId.equals(PUMP_FUN_PROGRAM_ID) || ix.programId.equals(new PublicKey("TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA")),
    ); //parsing inner instructions


    if (pumpFunIxs.length === 0) return;
    const events = PUMP_FUN_EVENT_PARSER.parseEvent(tx);
    
    const result = { instructions: pumpFunIxs, inner_ixs: pumpfun_amm_inner_ixs, events };
   
    return result;
  }catch(err){
    console.log(err);
  }
}

Rust

Detecting Buy/Sell Events

Once a valid Pump.fun transaction is identified and decoded, transactionOutput(parsedTxn) extracts key details about the buy or sell event, such as:

• TYPE: Whether it was a "buy" or "sell" action.

• MINT: The token's address involved in the swap.

• SIGNER: The wallet address that initiated the transaction (the buyer or seller).

• TOKEN AMOUNT: How much of the specific token was bought or sold.

• SOL AMOUNT: The amount of SOL exchanged in the transaction.

• SIGNATURE: The unique transaction signature, which can be used to view the transaction on a Solana block explorer.

Finally, these critical details are printed to the console in a clear, readable format, providing instant alerts for every buy and sell event occurring on Pump.fun. This allows traders and bots to react swiftly to market movements and liquidity changes.

Important Links

• Solana gRPC Documentation – In-depth technical docs for implementing real-time streaming with Yellowstone gRPC and Geyser plugin on Solana.

• Blogs on Solana gRPC Streaming – Guides, use cases, and performance benchmarks for building low-latency Solana applications using gRPC-based infrastructure.

• Solana DeFi Code Snippets & Examples – Ready-to-use code snippets and integrations for common DeFi protocols, transaction parsers, and real-time Solana data streaming use cases.