A sample Parser for M-PESA SMSs. This works as of Jan 24th 2018. The format of the SMSs might/will change in future and this will not be relevant any more.

SillyMpesaMessageParser.java

import java.util.HashMap;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * 24 Jan, 2018
 * Parses MPESA SMS String through simple String manipulation. And a tiny bit of regex :-D
 */
public class SillyMpesaMessageParser {

    public Map<String,String> parse(final String message){
        String[] exploded = message.toLowerCase().split(" ");

        //Get Transaction code
        String code = exploded[0];

        //Get transaction type
        String transactionType = getTransactionType(message.toLowerCase());

        //Get sender/recipient
        String participant = getParticipant(transactionType,message.toLowerCase());

        //Get mpesa amount
        String amount = "";
        String balance = "";
        String transactionCost = "";

        int moneyCount = 0;
        for(String str : exploded){
            if(str.startsWith("ksh")){
                String money = str.replace("ksh","");
                if(moneyCount == 0){
                    amount = money;
                }else if(moneyCount == 1){
                    balance = money.substring(0,money.length()-1);
                }else if(moneyCount == 2){
                    transactionCost = money.substring(0,money.length()-1);
                }
                moneyCount++;
            }
        }

        Map<String,String> parsed = new HashMap<>();
        parsed.put("type",transactionType.trim());
        parsed.put("code",code.trim());
        parsed.put("amount",amount.trim());
        parsed.put("balance",balance.trim());
        parsed.put("cost",transactionCost.trim());
        parsed.put("participant",participant.trim());
        return parsed;
    }

    private String getTransactionType(String message){
        String transactionType = "unknown";
        if(message.toLowerCase().contains("you have received")){
            transactionType = "received";
        }else if(message.toLowerCase().contains("sent to")){
            transactionType = "sent";
        }else if(message.toLowerCase().contains("withdraw")){
            transactionType = "withdraw";
        }else if(message.toLowerCase().contains("paid to")){
            transactionType = "paybill";
        }else if(message.toLowerCase().contains("you bought")){
            transactionType = "airtime";
        }
        return transactionType;
    }

    private String getParticipant(String transactionType, String msg){
        if(transactionType.equals("received")){
            Pattern findSubject = Pattern.compile("from(.*)on [1-9]");
            Matcher matcher = findSubject.matcher(msg);
            while (matcher.find()) {
                return matcher.group(1);
            }
        }else if(transactionType.equals("withdraw")){
            Pattern findSubject = Pattern.compile("from(.*)new m-pesa");
            Matcher matcher = findSubject.matcher(msg);
            while (matcher.find()) {
                return matcher.group(1);
            }
        }else if(transactionType.equals("sent") || transactionType.equals("paybill")){
            Pattern findSubject = Pattern.compile("to(.*)on [1-9]");
            Matcher matcher = findSubject.matcher(msg);
            while (matcher.find()) {
                return matcher.group(1);
            }
        }
        return "";
    }
}

SillyMpesaMessageParserTest.java

import org.junit.Before;
import org.junit.Test;

import java.util.Map;

import static org.junit.Assert.*;


public class SillyMpesaMessageParserTest {

    SillyMpesaMessageParser parser;

    @Before
    public void setUp() throws Exception {
        parser = new SillyMpesaMessageParser();
    }

    @Test
    public void testReceivedMpesa(){
        String msg = "MDDA561QDA Confirmed. You have received Ksh5,000.00 from JOHN DOE 0799654321 "+
                "on 15/1/18 at 7:00 PM. New M-PESA balance is Ksh6,000.00. Pay bills via M-PESA.";
        Map<String,String> response = parser.parse(msg);

        assertEquals("received",response.get("type"));
        assertEquals("MDDA561QDA".toLowerCase(),response.get("code"));// Gets the correct transaction code
        assertEquals("JOHN DOE 0799654321".toLowerCase(),response.get("participant"));// Gets the correct sender
        assertEquals("5,000.00",response.get("amount"));
        assertEquals("6,000.00",response.get("balance"));
        assertEquals("",response.get("cost"));
    }

    @Test
    public void testSentMpesa(){
        String msg = "MDDA561QDA Confirmed. Ksh5,000.00 sent to JOHN DOE 0799654321 "+
                "on 15/1/18 at 7:00 PM. New M-PESA balance is Ksh500.00. Transaction cost, Ksh27.00.";
        Map<String,String> response = parser.parse(msg);

        assertEquals("sent",response.get("type"));
        assertEquals("MDDA561QDA".toLowerCase(),response.get("code"));// Gets the correct transaction code
        assertEquals("JOHN DOE 0799654321".toLowerCase(),response.get("participant"));// Gets the correct sender
        assertEquals("5,000.00",response.get("amount"));
        assertEquals("500.00",response.get("balance"));
        assertEquals("27.00",response.get("cost"));
    }

    @Test
    public void testWithdrawMpesa(){
        String msg = "MDDA561QDA Confirmed.on 15/1/18 at 7:00 PMWithdraw Ksh2,000.00 from 99999 - Super Agent "+
                "New M-PESA balance is Ksh900.00. Transaction cost, Ksh27.00.";
        Map<String,String> response = parser.parse(msg);

        assertEquals("withdraw",response.get("type"));
        assertEquals("MDDA561QDA".toLowerCase(),response.get("code"));// Gets the correct transaction code
        assertEquals("99999 - Super Agent".toLowerCase(),response.get("participant"));// Gets the correct sender
        assertEquals("2,000.00",response.get("amount"));
        assertEquals("900.00",response.get("balance"));
        assertEquals("27.00",response.get("cost"));
    }

    @Test
    public void testPaybillMpesa(){
        String msg = "MDDA561QDA Confirmed. Ksh5,000.00 paid to AWESOME MARKET. on 15/1/18 at 7:00 PM. "+
                "New M-PESA balance is Ksh900.00. Transaction cost, Ksh0.00.";
        Map<String,String> response = parser.parse(msg);

        assertEquals("paybill",response.get("type"));
        assertEquals("MDDA561QDA".toLowerCase(),response.get("code"));// Gets the correct transaction code
        assertEquals("AWESOME MARKET.".toLowerCase(),response.get("participant"));// Gets the correct sender
        assertEquals("5,000.00",response.get("amount"));
        assertEquals("900.00",response.get("balance"));
        assertEquals("0.00",response.get("cost"));
    }
}