diff --git a/packages/core-go/address/detect.go b/packages/core-go/address/detect.go
index def03d2..ffd5b4e 100644
--- a/packages/core-go/address/detect.go
+++ b/packages/core-go/address/detect.go
@@ -6,14 +6,15 @@ func Detect(addr string) (AddressKind, error) {
 		return "", err
 	}
 
-	switch versionByte {
-	case VersionByteG:
-		return KindG, nil
-	case VersionByteM:
-		return KindM, nil
-	case VersionByteC:
-		return KindC, nil
-	default:
-		return "", ErrUnknownVersionByteError
+func Detect(address string) string {
+	if strkey.IsValidEd25519PublicKey(address) {
+		return "G"
 	}
+	if strkey.IsValidMuxedAccountEd25519PublicKey(address) {
+		return "M"
+	}
+	if _, err := strkey.Decode(strkey.VersionByteContract, address); err == nil {
+		return "C"
+	}
+	return "invalid"
 }
diff --git a/packages/core-go/address/result.go b/packages/core-go/address/result.go
index 0255f54..2c035a8 100644
--- a/packages/core-go/address/result.go
+++ b/packages/core-go/address/result.go
@@ -6,3 +6,9 @@ type ParseResult struct {
 	Warnings []Warning
 	Err      *AddressError
 }
+
+type AddressError struct {
+	Code    ErrorCode
+	Input   string
+	Message string
+}
diff --git a/packages/core-go/muxed/decode.go b/packages/core-go/muxed/decode.go
index 12e81b2..9008bf6 100644
--- a/packages/core-go/muxed/decode.go
+++ b/packages/core-go/muxed/decode.go
@@ -7,28 +7,16 @@ import (
 	"github.com/stellar-address-kit/core-go/address"
 )
 
-// muxedPayloadSize is the expected raw payload length after stripping the
-// version byte and checksum: 8 bytes (uint64 ID) + 32 bytes (Ed25519 key).
-const muxedPayloadSize = 40
-
-func DecodeMuxed(mAddress string) (string, uint64, error) {
-	_, payload, err := address.DecodeStrKey(mAddress)
+func DecodeMuxed(mAddress string) (string, string, error) {
+	muxedAccount, err := strkey.DecodeMuxedAccount(mAddress)
 	if err != nil {
-		return "", 0, err
+		return "", "", err
 	}
 
-	if len(payload) != muxedPayloadSize {
-		return "", 0, fmt.Errorf("invalid muxed address payload length: %d", len(payload))
-	}
-
-	// Muxed payload layout: [32-byte Ed25519 key][8-byte big-endian uint64 ID]
-	keyBytes := payload[:32]
-	id := binary.BigEndian.Uint64(payload[32:])
-
-	baseG, err := address.EncodeStrKey(address.VersionByteG, keyBytes)
+	baseG, err := muxedAccount.AccountID()
 	if err != nil {
 		return "", 0, err
 	}
 
-	return baseG, id, nil
+	return baseG, strconv.FormatUint(muxedAccount.ID(), 10), nil
 }
diff --git a/packages/core-go/muxed/encode.go b/packages/core-go/muxed/encode.go
index 0a56b66..6db9224 100644
--- a/packages/core-go/muxed/encode.go
+++ b/packages/core-go/muxed/encode.go
@@ -2,15 +2,18 @@ package muxed
 
 import (
 	"fmt"
-	"strconv"
+	"math/big"
 
 	"github.com/stellar/go/strkey"
 )
 
 func EncodeMuxed(baseG string, id string) (string, error) {
-	idUint, err := strconv.ParseUint(id, 10, 64)
-	if err != nil {
-		return "", fmt.Errorf("invalid muxed account id %q: %w", id, err)
+	idInt := new(big.Int)
+	if _, ok := idInt.SetString(id, 10); !ok {
+		return "", fmt.Errorf("invalid muxed account id %q", id)
+	}
+	if idInt.Sign() < 0 || idInt.BitLen() > 64 {
+		return "", fmt.Errorf("muxed account id %q exceeds uint64", id)
 	}
 
 	var muxedAccount strkey.MuxedAccount
@@ -18,6 +21,6 @@ func EncodeMuxed(baseG string, id string) (string, error) {
 		return "", err
 	}
 
-	muxedAccount.SetID(idUint)
+	muxedAccount.SetID(idInt.Uint64())
 	return muxedAccount.Address()
 }
diff --git a/packages/core-go/routing/extract.go b/packages/core-go/routing/extract.go
index 17b05aa..c1a1a4a 100644
--- a/packages/core-go/routing/extract.go
+++ b/packages/core-go/routing/extract.go
@@ -77,8 +77,8 @@ func ExtractRouting(input RoutingInput) RoutingResult {
 		}
 	}
 
-	if parsed.Kind == address.KindM {
-		baseG, id, err := muxed.DecodeMuxed(parsed.Raw)
+	if parsed.Kind == "M" {
+		baseG, id, err := muxed.DecodeMuxed(parsed.Address)
 		if err != nil {
 			return RoutingResult{
 				RoutingSource: "none",
@@ -90,9 +90,10 @@ func ExtractRouting(input RoutingInput) RoutingResult {
 			}
 		}
 
-		warnings := []address.Warning{}
+		warnings := append([]address.Warning{}, parsed.Warnings...)
+		memoValue := stringValue(input.MemoValue)
 
-		if input.MemoType == "id" || (input.MemoType == "text" && digitsOnlyRegex.MatchString(input.MemoValue)) {
+		if input.MemoType == "id" || (input.MemoType == "text" && digitsOnlyRegex.MatchString(memoValue)) {
 			warnings = append(warnings, address.Warning{
 				Code:     address.WarnMemoPresentWithMuxed,
 				Severity: "warn",
@@ -108,19 +109,26 @@ func ExtractRouting(input RoutingInput) RoutingResult {
 
 		return RoutingResult{
 			DestinationBaseAccount: baseG,
-			RoutingID:              &id,
+			RoutingID:              NewRoutingID(id),
 			RoutingSource:          "muxed",
 			Warnings:               warnings,
 		}
 	}
 
-	routingID := (*uint64)(nil)
+	var routingID *RoutingID
 	routingSource := "none"
-	warnings := []address.Warning{}
+	warnings := append([]address.Warning{}, parsed.Warnings...)
+	memoValue := stringValue(input.MemoValue)
 
 	if input.MemoType == "id" {
-		val, parseErr := strconv.ParseUint(input.MemoValue, 10, 64)
-		if parseErr != nil {
+		norm := NormalizeMemoTextID(memoValue)
+		if norm.Normalized != "" {
+			routingID = NewRoutingID(norm.Normalized)
+			routingSource = "memo"
+		}
+		warnings = append(warnings, norm.Warnings...)
+
+		if norm.Normalized == "" {
 			warnings = append(warnings, address.Warning{
 				Code:     address.WarnMemoIDInvalidFormat,
 				Severity: "warn",
@@ -142,11 +150,10 @@ func ExtractRouting(input RoutingInput) RoutingResult {
 			routingID = &val
 			routingSource = "memo"
 		}
-	} else if input.MemoType == "text" && input.MemoValue != "" {
-		norm := NormalizeMemoTextID(input.MemoValue)
+	} else if input.MemoType == "text" && memoValue != "" {
+		norm := NormalizeMemoTextID(memoValue)
 		if norm.Normalized != "" {
-			parsedID, _ := strconv.ParseUint(norm.Normalized, 10, 64)
-			routingID = &parsedID
+			routingID = NewRoutingID(norm.Normalized)
 			routingSource = "memo"
 			warnings = append(warnings, norm.Warnings...)
 		} else {
@@ -182,4 +189,12 @@ func ExtractRouting(input RoutingInput) RoutingResult {
 		RoutingSource:          routingSource,
 		Warnings:               warnings,
 	}
-}
\ No newline at end of file
+}
+
+func stringValue(s *string) string {
+	if s == nil {
+		return ""
+	}
+
+	return *s
+}
diff --git a/packages/core-go/routing/result.go b/packages/core-go/routing/result.go
index 137eedd..d0374c4 100644
--- a/packages/core-go/routing/result.go
+++ b/packages/core-go/routing/result.go
@@ -4,6 +4,8 @@ import (
 	"encoding/json"
 	"fmt"
 	"strconv"
+
+	"github.com/stellar-address-kit/core-go/address"
 )
 
 type MemoType string
@@ -65,3 +67,16 @@ func (r *RoutingID) Uint64() (uint64, error) {
 func NewRoutingID(s string) *RoutingID {
 	return &RoutingID{raw: s}
 }
+
+type RoutingResult struct {
+	DestinationBaseAccount string
+	RoutingID              *RoutingID
+	RoutingSource          string // "muxed" | "memo" | "none"
+	Warnings               []address.Warning
+	DestinationError       *DestinationError
+}
+
+type DestinationError struct {
+	Code    address.ErrorCode
+	Message string
+}