diff --git a/encoding/jsonpb/encode.go b/encoding/jsonpb/encode.go
new file mode 100644
index 0000000..928b24f
--- /dev/null
+++ b/encoding/jsonpb/encode.go
@@ -0,0 +1,231 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package jsonpb
+
+import (
+	"encoding/base64"
+	"math"
+	"sort"
+
+	"github.com/golang/protobuf/v2/internal/encoding/json"
+	"github.com/golang/protobuf/v2/internal/errors"
+	"github.com/golang/protobuf/v2/internal/pragma"
+	"github.com/golang/protobuf/v2/proto"
+	pref "github.com/golang/protobuf/v2/reflect/protoreflect"
+)
+
+// Marshal writes the given proto.Message in JSON format using default options.
+func Marshal(m proto.Message) ([]byte, error) {
+	return MarshalOptions{}.Marshal(m)
+}
+
+// MarshalOptions is a configurable JSON format marshaler.
+type MarshalOptions struct {
+	pragma.NoUnkeyedLiterals
+
+	// Set Compact to true to have output in a single line with no line breaks.
+	Compact bool
+}
+
+// Marshal writes the given proto.Message in JSON format using options in MarshalOptions object.
+func (o MarshalOptions) Marshal(m proto.Message) ([]byte, error) {
+	var nerr errors.NonFatal
+	v, err := o.marshalMessage(m.ProtoReflect())
+	if !nerr.Merge(err) {
+		return nil, err
+	}
+
+	indent := "  "
+	if o.Compact {
+		indent = ""
+	}
+
+	b, err := json.Marshal(v, indent)
+	if !nerr.Merge(err) {
+		return nil, err
+	}
+	return b, nerr.E
+}
+
+// marshalMessage converts a protoreflect.Message to a json.Value.
+func (o MarshalOptions) marshalMessage(m pref.Message) (json.Value, error) {
+	var nerr errors.NonFatal
+	var msgFields [][2]json.Value
+
+	msgType := m.Type()
+	fieldDescs := msgType.Fields()
+	knownFields := m.KnownFields()
+	size := fieldDescs.Len()
+	for i := 0; i < size; i++ {
+		fd := fieldDescs.Get(i)
+		num := fd.Number()
+
+		if !knownFields.Has(num) {
+			if fd.Cardinality() == pref.Required {
+				// Treat unset required fields as a non-fatal error.
+				nerr.AppendRequiredNotSet(string(fd.FullName()))
+			}
+			continue
+		}
+
+		name := json.ValueOf(fd.JSONName())
+		pval := knownFields.Get(num)
+		var err error
+		msgFields, err = o.appendField(msgFields, name, pval, fd)
+		if !nerr.Merge(err) {
+			return json.Value{}, err
+		}
+	}
+
+	return json.ValueOf(msgFields), nerr.E
+}
+
+// appendField marshals a protoreflect.Value and appends it to the given
+// [][2]json.Value.
+func (o MarshalOptions) appendField(msgFields [][2]json.Value, name json.Value, pval pref.Value, fd pref.FieldDescriptor) ([][2]json.Value, error) {
+	var nerr errors.NonFatal
+	var jval json.Value
+	var err error
+
+	if fd.Cardinality() == pref.Repeated {
+		// Map or repeated fields.
+		if fd.IsMap() {
+			jval, err = o.marshalMap(pval.Map(), fd)
+			if !nerr.Merge(err) {
+				return msgFields, err
+			}
+		} else {
+			jval, err = o.marshalList(pval.List(), fd)
+			if !nerr.Merge(err) {
+				return msgFields, err
+			}
+		}
+	} else {
+		// Required or optional fields.
+		jval, err = o.marshalSingular(pval, fd)
+		if !nerr.Merge(err) {
+			return msgFields, err
+		}
+	}
+
+	msgFields = append(msgFields, [2]json.Value{name, jval})
+	return msgFields, nerr.E
+}
+
+// marshalSingular converts a non-repeated field value to json.Value.
+// This includes all scalar types, enums, messages, and groups.
+func (o MarshalOptions) marshalSingular(val pref.Value, fd pref.FieldDescriptor) (json.Value, error) {
+	kind := fd.Kind()
+	switch kind {
+	case pref.BoolKind, pref.StringKind,
+		pref.Int32Kind, pref.Sint32Kind, pref.Uint32Kind,
+		pref.Sfixed32Kind, pref.Fixed32Kind:
+		return json.ValueOf(val.Interface()), nil
+
+	case pref.Int64Kind, pref.Sint64Kind, pref.Uint64Kind,
+		pref.Sfixed64Kind, pref.Fixed64Kind:
+		return json.ValueOf(val.String()), nil
+
+	case pref.FloatKind, pref.DoubleKind:
+		n := val.Float()
+		switch {
+		case math.IsNaN(n):
+			return json.ValueOf("NaN"), nil
+		case math.IsInf(n, +1):
+			return json.ValueOf("Infinity"), nil
+		case math.IsInf(n, -1):
+			return json.ValueOf("-Infinity"), nil
+		default:
+			return json.ValueOf(n), nil
+		}
+
+	case pref.BytesKind:
+		return json.ValueOf(base64.StdEncoding.EncodeToString(val.Bytes())), nil
+
+	case pref.EnumKind:
+		num := val.Enum()
+		if desc := fd.EnumType().Values().ByNumber(num); desc != nil {
+			return json.ValueOf(string(desc.Name())), nil
+		}
+		// Use numeric value if there is no enum value descriptor.
+		return json.ValueOf(int32(num)), nil
+
+	case pref.MessageKind, pref.GroupKind:
+		return o.marshalMessage(val.Message())
+	}
+
+	return json.Value{}, errors.New("%v has unknown kind: %v", fd.FullName(), kind)
+}
+
+// marshalList converts a protoreflect.List to json.Value.
+func (o MarshalOptions) marshalList(list pref.List, fd pref.FieldDescriptor) (json.Value, error) {
+	var nerr errors.NonFatal
+	size := list.Len()
+	values := make([]json.Value, 0, size)
+
+	for i := 0; i < size; i++ {
+		item := list.Get(i)
+		val, err := o.marshalSingular(item, fd)
+		if !nerr.Merge(err) {
+			return json.Value{}, err
+		}
+		values = append(values, val)
+	}
+
+	return json.ValueOf(values), nerr.E
+}
+
+type mapEntry struct {
+	key   pref.MapKey
+	value pref.Value
+}
+
+// marshalMap converts a protoreflect.Map to json.Value.
+func (o MarshalOptions) marshalMap(mmap pref.Map, fd pref.FieldDescriptor) (json.Value, error) {
+	msgFields := fd.MessageType().Fields()
+	keyType := msgFields.ByNumber(1)
+	valType := msgFields.ByNumber(2)
+
+	// Get a sorted list based on keyType first.
+	entries := make([]mapEntry, 0, mmap.Len())
+	mmap.Range(func(key pref.MapKey, val pref.Value) bool {
+		entries = append(entries, mapEntry{key: key, value: val})
+		return true
+	})
+	sortMap(keyType.Kind(), entries)
+
+	// Convert to list of [2]json.Value.
+	var nerr errors.NonFatal
+	values := make([][2]json.Value, 0, len(entries))
+	for _, entry := range entries {
+		jkey := json.ValueOf(entry.key.String())
+		jval, err := o.marshalSingular(entry.value, valType)
+		if !nerr.Merge(err) {
+			return json.Value{}, err
+		}
+		values = append(values, [2]json.Value{jkey, jval})
+	}
+	return json.ValueOf(values), nerr.E
+}
+
+// sortMap orders list based on value of key field for deterministic output.
+func sortMap(keyKind pref.Kind, values []mapEntry) {
+	less := func(i, j int) bool {
+		return values[i].key.String() < values[j].key.String()
+	}
+	switch keyKind {
+	case pref.Int32Kind, pref.Sint32Kind, pref.Sfixed32Kind,
+		pref.Int64Kind, pref.Sint64Kind, pref.Sfixed64Kind:
+		less = func(i, j int) bool {
+			return values[i].key.Int() < values[j].key.Int()
+		}
+	case pref.Uint32Kind, pref.Fixed32Kind,
+		pref.Uint64Kind, pref.Fixed64Kind:
+		less = func(i, j int) bool {
+			return values[i].key.Uint() < values[j].key.Uint()
+		}
+	}
+	sort.Slice(values, less)
+}