diff --git a/twins/api/http/endpoint_states_test.go b/twins/api/http/endpoint_states_test.go
new file mode 100644
index 00000000..33a9561c
--- /dev/null
+++ b/twins/api/http/endpoint_states_test.go
@@ -0,0 +1,213 @@
+// Copyright (c) Mainflux
+// SPDX-License-Identifier: Apache-2.0
+
+package http_test
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"testing"
+
+	"github.com/mainflux/mainflux/twins"
+	"github.com/mainflux/senml"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/mainflux/mainflux/twins/mocks"
+)
+
+const (
+	nanosec = 1e9
+
+	attrName1     = "temperature"
+	attrSubtopic1 = "engine"
+	attrName2     = "humidity"
+	attrSubtopic2 = "chassis"
+
+	publisher = "twins"
+)
+
+type stateRes struct {
+	TwinID     string                 `json:"twin_id"`
+	ID         int64                  `json:"id"`
+	Definition int                    `json:"definition"`
+	Payload    map[string]interface{} `json:"payload"`
+}
+
+type statesPageRes struct {
+	pageRes
+	States []stateRes `json:"states"`
+}
+
+func TestListStates(t *testing.T) {
+	svc := mocks.NewService(map[string]string{token: email})
+	ts := newServer(svc)
+	defer ts.Close()
+
+	twin := twins.Twin{
+		Owner: email,
+	}
+	def := mocks.CreateDefinition([]string{attrName1, attrName2}, []string{attrSubtopic1, attrSubtopic2})
+	tw, err := svc.AddTwin(context.Background(), token, twin, def)
+	require.Nil(t, err, fmt.Sprintf("unexpected error: %s", err))
+	attr := def.Attributes[0]
+
+	recs := mocks.CreateSenML(100, attrName1)
+	message, err := mocks.CreateMessage(attr, recs)
+	require.Nil(t, err, fmt.Sprintf("unexpected error: %s", err))
+	err = svc.SaveStates(message)
+	require.Nil(t, err, fmt.Sprintf("unexpected error: %s", err))
+
+	var data []stateRes
+	for i := 0; i < len(recs); i++ {
+		res := createStateResponse(i, tw, recs[i])
+		data = append(data, res)
+	}
+
+	baseURL := fmt.Sprintf("%s/states/%s", ts.URL, tw.ID)
+	queryFmt := "%s?offset=%d&limit=%d"
+	cases := []struct {
+		desc   string
+		auth   string
+		status int
+		url    string
+		res    []stateRes
+	}{
+		{
+			desc:   "get a list of states",
+			auth:   token,
+			status: http.StatusOK,
+			url:    baseURL,
+			res:    data[0:10],
+		},
+		{
+			desc:   "get a list of states with valid offset and limit",
+			auth:   token,
+			status: http.StatusOK,
+			url:    fmt.Sprintf(queryFmt, baseURL, 20, 15),
+			res:    data[20:35],
+		},
+		{
+			desc:   "get a list of states with invalid token",
+			auth:   wrongValue,
+			status: http.StatusForbidden,
+			url:    fmt.Sprintf(queryFmt, baseURL, 0, 5),
+			res:    nil,
+		},
+		{
+			desc:   "get a list of states with empty token",
+			auth:   "",
+			status: http.StatusForbidden,
+			url:    fmt.Sprintf(queryFmt, baseURL, 0, 5),
+			res:    nil,
+		},
+		{
+			desc:   "get a list of states with + limit > total",
+			auth:   token,
+			status: http.StatusOK,
+			url:    fmt.Sprintf(queryFmt, baseURL, 91, 20),
+			res:    data[91:],
+		},
+		{
+			desc:   "get a list of states with negative offset",
+			auth:   token,
+			status: http.StatusBadRequest,
+			url:    fmt.Sprintf(queryFmt, baseURL, -1, 5),
+			res:    nil,
+		},
+		{
+			desc:   "get a list of states with negative limit",
+			auth:   token,
+			status: http.StatusBadRequest,
+			url:    fmt.Sprintf(queryFmt, baseURL, 0, -5),
+			res:    nil,
+		},
+		{
+			desc:   "get a list of states with zero limit",
+			auth:   token,
+			status: http.StatusBadRequest,
+			url:    fmt.Sprintf(queryFmt, baseURL, 0, 0),
+			res:    nil,
+		},
+		{
+			desc:   "get a list of states with limit greater than max",
+			auth:   token,
+			status: http.StatusBadRequest,
+			url:    fmt.Sprintf(queryFmt, baseURL, 0, 110),
+			res:    nil,
+		},
+		{
+			desc:   "get a list of states with invalid offset",
+			auth:   token,
+			status: http.StatusBadRequest,
+			url:    fmt.Sprintf("%s?offset=invalid&limit=%d", baseURL, 15),
+			res:    nil,
+		},
+		{
+			desc:   "get a list of states with invalid limit",
+			auth:   token,
+			status: http.StatusBadRequest,
+			url:    fmt.Sprintf("%s?offset=%d&limit=invalid", baseURL, 0),
+			res:    nil,
+		},
+		{
+			desc:   "get a list of states without offset",
+			auth:   token,
+			status: http.StatusOK,
+			url:    fmt.Sprintf("%s?limit=%d", baseURL, 15),
+			res:    data[0:15],
+		},
+		{
+			desc:   "get a list of states without limit",
+			auth:   token,
+			status: http.StatusOK,
+			url:    fmt.Sprintf("%s?offset=%d", baseURL, 14),
+			res:    data[14:24],
+		},
+		{
+			desc:   "get a list of states with invalid number of parameters",
+			auth:   token,
+			status: http.StatusBadRequest,
+			url:    fmt.Sprintf("%s%s", baseURL, "?offset=4&limit=4&limit=5&offset=5"),
+			res:    nil,
+		},
+		{
+			desc:   "get a list of states with redundant query parameters",
+			auth:   token,
+			status: http.StatusOK,
+			url:    fmt.Sprintf("%s?offset=%d&limit=%d&value=something", baseURL, 0, 5),
+			res:    data[0:5],
+		},
+	}
+
+	for _, tc := range cases {
+		req := testRequest{
+			client: ts.Client(),
+			method: http.MethodGet,
+			url:    tc.url,
+			token:  tc.auth,
+		}
+		res, err := req.make()
+		assert.Nil(t, err, fmt.Sprintf("%s: unexpected error %s", tc.desc, err))
+
+		var resData statesPageRes
+		if tc.res != nil {
+			err = json.NewDecoder(res.Body).Decode(&resData)
+			assert.Nil(t, err, fmt.Sprintf("%s: unexpected error %s", tc.desc, err))
+		}
+
+		assert.Equal(t, tc.status, res.StatusCode, fmt.Sprintf("%s: expected status code %d got %d", tc.desc, tc.status, res.StatusCode))
+		assert.ElementsMatch(t, tc.res, resData.States, fmt.Sprintf("%s: expected body %v got %v", tc.desc, tc.res, resData.States))
+	}
+}
+
+func createStateResponse(id int, tw twins.Twin, rec senml.Record) stateRes {
+	return stateRes{
+		TwinID:     tw.ID,
+		ID:         int64(id),
+		Definition: tw.Definitions[len(tw.Definitions)-1].ID,
+		Payload:    map[string]interface{}{rec.BaseName: nil},
+	}
+}
diff --git a/twins/api/http/endpoint_test.go b/twins/api/http/endpoint_twins_test.go
similarity index 60%
rename from twins/api/http/endpoint_test.go
rename to twins/api/http/endpoint_twins_test.go
index f853b5ed..537e529e 100644
--- a/twins/api/http/endpoint_test.go
+++ b/twins/api/http/endpoint_twins_test.go
@@ -8,13 +8,11 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net/http"
 	"net/http/httptest"
 	"strconv"
 	"strings"
 	"testing"
-	"time"
 
 	"github.com/mainflux/mainflux/twins"
 	httpapi "github.com/mainflux/mainflux/twins/api/http"
@@ -38,6 +36,31 @@ const (
 
 var invalidName = strings.Repeat("m", maxNameSize+1)
 
+type twinReq struct {
+	token    string
+	Name     string                 `json:"name,omitempty"`
+	Metadata map[string]interface{} `json:"metadata,omitempty"`
+}
+
+type twinRes struct {
+	Owner    string                 `json:"owner"`
+	ID       string                 `json:"id"`
+	Name     string                 `json:"name,omitempty"`
+	Revision int                    `json:"revision"`
+	Metadata map[string]interface{} `json:"metadata,omitempty"`
+}
+
+type pageRes struct {
+	Total  uint64 `json:"total"`
+	Offset uint64 `json:"offset"`
+	Limit  uint64 `json:"limit"`
+}
+
+type twinsPageRes struct {
+	pageRes
+	Twins []twinRes `json:"twins"`
+}
+
 type testRequest struct {
 	client      *http.Client
 	method      string
@@ -61,16 +84,6 @@ func (tr testRequest) make() (*http.Response, error) {
 	return tr.client.Do(req)
 }
 
-func newService(tokens map[string]string) twins.Service {
-	auth := mocks.NewAuthNServiceClient(tokens)
-	twinsRepo := mocks.NewTwinRepository()
-	statesRepo := mocks.NewStateRepository()
-	idp := mocks.NewIdentityProvider()
-	subs := map[string]string{"chanID": "chanID"}
-	broker := mocks.New(subs)
-	return twins.New(broker, auth, twinsRepo, statesRepo, idp, "chanID", nil)
-}
-
 func newServer(svc twins.Service) *httptest.Server {
 	mux := httpapi.MakeHandler(mocktracer.New(), svc)
 	return httptest.NewServer(mux)
@@ -82,7 +95,7 @@ func toJSON(data interface{}) string {
 }
 
 func TestAddTwin(t *testing.T) {
-	svc := newService(map[string]string{token: email})
+	svc := mocks.NewService(map[string]string{token: email})
 	ts := newServer(svc)
 	defer ts.Close()
 
@@ -185,13 +198,14 @@ func TestAddTwin(t *testing.T) {
 }
 
 func TestUpdateTwin(t *testing.T) {
-	svc := newService(map[string]string{token: email})
+	svc := mocks.NewService(map[string]string{token: email})
 	ts := newServer(svc)
 	defer ts.Close()
 
 	twin := twins.Twin{}
 	def := twins.Definition{}
-	stw, _ := svc.AddTwin(context.Background(), token, twin, def)
+	stw, err := svc.AddTwin(context.Background(), token, twin, def)
+	require.Nil(t, err, fmt.Sprintf("unexpected error: %s", err))
 
 	twin.Name = twinName
 	data := toJSON(twin)
@@ -297,7 +311,7 @@ func TestUpdateTwin(t *testing.T) {
 }
 
 func TestViewTwin(t *testing.T) {
-	svc := newService(map[string]string{token: email})
+	svc := mocks.NewService(map[string]string{token: email})
 	ts := newServer(svc)
 	defer ts.Close()
 
@@ -307,58 +321,54 @@ func TestViewTwin(t *testing.T) {
 	require.Nil(t, err, fmt.Sprintf("unexpected error: %s", err))
 
 	twres := twinRes{
-		Owner:       stw.Owner,
-		Name:        stw.Name,
-		ID:          stw.ID,
-		Revision:    stw.Revision,
-		Created:     stw.Created,
-		Updated:     stw.Updated,
-		Definitions: stw.Definitions,
-		Metadata:    stw.Metadata,
+		Owner:    stw.Owner,
+		Name:     stw.Name,
+		ID:       stw.ID,
+		Revision: stw.Revision,
+		Metadata: stw.Metadata,
 	}
-	data := toJSON(twres)
 
 	cases := []struct {
 		desc   string
 		id     string
 		auth   string
 		status int
-		res    string
+		res    twinRes
 	}{
 		{
 			desc:   "view existing twin",
 			id:     stw.ID,
 			auth:   token,
 			status: http.StatusOK,
-			res:    data,
+			res:    twres,
 		},
 		{
 			desc:   "view non-existent twin",
 			id:     strconv.FormatUint(wrongID, 10),
 			auth:   token,
 			status: http.StatusNotFound,
-			res:    "",
+			res:    twinRes{},
 		},
 		{
 			desc:   "view twin by passing invalid token",
 			id:     stw.ID,
 			auth:   wrongValue,
 			status: http.StatusForbidden,
-			res:    "",
+			res:    twinRes{},
 		},
 		{
 			desc:   "view twin by passing empty id",
 			id:     "",
 			auth:   token,
 			status: http.StatusBadRequest,
-			res:    "",
+			res:    twinRes{},
 		},
 		{
 			desc:   "view twin by passing empty token",
 			id:     stw.ID,
 			auth:   "",
 			status: http.StatusForbidden,
-			res:    "",
+			res:    twinRes{},
 		},
 	}
 
@@ -372,20 +382,197 @@ func TestViewTwin(t *testing.T) {
 		res, err := req.make()
 		assert.Nil(t, err, fmt.Sprintf("%s: unexpected error %s", tc.desc, err))
 		assert.Equal(t, tc.status, res.StatusCode, fmt.Sprintf("%s: expected status code %d got %d", tc.desc, tc.status, res.StatusCode))
-		body, err := ioutil.ReadAll(res.Body)
-		data := strings.Trim(string(body), "\n")
-		assert.Equal(t, tc.res, data, fmt.Sprintf("%s: expected body %s got %s", tc.desc, tc.res, data))
+
+		var resData twinRes
+		err = json.NewDecoder(res.Body).Decode(&resData)
+		assert.Equal(t, tc.res, resData, fmt.Sprintf("%s: expected body %v got %v", tc.desc, tc.res, resData))
+	}
+}
+
+func TestListTwins(t *testing.T) {
+	svc := mocks.NewService(map[string]string{token: email})
+	ts := newServer(svc)
+	defer ts.Close()
+
+	var data []twinRes
+	for i := 0; i < 100; i++ {
+		name := fmt.Sprintf("%s-%d", twinName, i)
+		twin := twins.Twin{
+			Owner: email,
+			Name:  name,
+		}
+		tw, err := svc.AddTwin(context.Background(), token, twin, twins.Definition{})
+		require.Nil(t, err, fmt.Sprintf("unexpected error: %s", err))
+		twres := twinRes{
+			Owner:    tw.Owner,
+			ID:       tw.ID,
+			Name:     tw.Name,
+			Revision: tw.Revision,
+			Metadata: tw.Metadata,
+		}
+		data = append(data, twres)
+	}
+
+	baseURL := fmt.Sprintf("%s/twins", ts.URL)
+	queryFmt := "%s?offset=%d&limit=%d"
+	cases := []struct {
+		desc   string
+		auth   string
+		status int
+		url    string
+		res    []twinRes
+	}{
+		{
+			desc:   "get a list of twins",
+			auth:   token,
+			status: http.StatusOK,
+			url:    baseURL,
+			res:    data[0:10],
+		},
+		{
+			desc:   "get a list of twins with invalid token",
+			auth:   wrongValue,
+			status: http.StatusForbidden,
+			url:    fmt.Sprintf(queryFmt, baseURL, 0, 1),
+			res:    nil,
+		},
+		{
+			desc:   "get a list of twins with empty token",
+			auth:   "",
+			status: http.StatusForbidden,
+			url:    fmt.Sprintf(queryFmt, baseURL, 0, 1),
+			res:    nil,
+		},
+		{
+			desc:   "get a list of twins with valid offset and limit",
+			auth:   token,
+			status: http.StatusOK,
+			url:    fmt.Sprintf(queryFmt, baseURL, 25, 40),
+			res:    data[25:65],
+		},
+		{
+			desc:   "get a list of twins with offset + limit > total",
+			auth:   token,
+			status: http.StatusOK,
+			url:    fmt.Sprintf(queryFmt, baseURL, 91, 20),
+			res:    data[91:],
+		},
+		{
+			desc:   "get a list of twins with negative offset",
+			auth:   token,
+			status: http.StatusBadRequest,
+			url:    fmt.Sprintf(queryFmt, baseURL, -1, 5),
+			res:    nil,
+		},
+		{
+			desc:   "get a list of twins with negative limit",
+			auth:   token,
+			status: http.StatusBadRequest,
+			url:    fmt.Sprintf(queryFmt, baseURL, 1, -5),
+			res:    nil,
+		},
+		{
+			desc:   "get a list of twins with zero limit",
+			auth:   token,
+			status: http.StatusBadRequest,
+			url:    fmt.Sprintf(queryFmt, baseURL, 1, 0),
+			res:    nil,
+		},
+		{
+			desc:   "get a list of twins with limit greater than max",
+			auth:   token,
+			status: http.StatusBadRequest,
+			url:    fmt.Sprintf("%s?offset=%d&limit=%d", baseURL, 0, 110),
+			res:    nil,
+		},
+		{
+			desc:   "get a list of twins with invalid offset",
+			auth:   token,
+			status: http.StatusBadRequest,
+			url:    fmt.Sprintf("%s%s", baseURL, "?offset=e&limit=5"),
+			res:    nil,
+		},
+		{
+			desc:   "get a list of twins with invalid limit",
+			auth:   token,
+			status: http.StatusBadRequest,
+			url:    fmt.Sprintf("%s%s", baseURL, "?offset=5&limit=e"),
+			res:    nil,
+		},
+		{
+			desc:   "get a list of twins without offset",
+			auth:   token,
+			status: http.StatusOK,
+			url:    fmt.Sprintf("%s?limit=%d", baseURL, 5),
+			res:    data[0:5],
+		},
+		{
+			desc:   "get a list of twins without limit",
+			auth:   token,
+			status: http.StatusOK,
+			url:    fmt.Sprintf("%s?offset=%d", baseURL, 1),
+			res:    data[1:11],
+		},
+		{
+			desc:   "get a list of twins with invalid number of parameters",
+			auth:   token,
+			status: http.StatusBadRequest,
+			url:    fmt.Sprintf("%s%s", baseURL, "?offset=4&limit=4&limit=5&offset=5"),
+			res:    nil,
+		},
+		{
+			desc:   "get a list of twins with redundant query parameters",
+			auth:   token,
+			status: http.StatusOK,
+			url:    fmt.Sprintf("%s?offset=%d&limit=%d&value=something", baseURL, 0, 5),
+			res:    data[0:5],
+		},
+		{
+			desc:   "get a list of twins filtering with invalid name",
+			auth:   token,
+			status: http.StatusBadRequest,
+			url:    fmt.Sprintf("%s?offset=%d&limit=%d&name=%s", baseURL, 0, 5, invalidName),
+			res:    nil,
+		},
+		{
+			desc:   "get a list of twins filtering with valid name",
+			auth:   token,
+			status: http.StatusOK,
+			url:    fmt.Sprintf("%s?offset=%d&limit=%d&name=%s", baseURL, 2, 1, twinName+"-2"),
+			res:    data[2:3],
+		},
+	}
+
+	for _, tc := range cases {
+		req := testRequest{
+			client: ts.Client(),
+			method: http.MethodGet,
+			url:    tc.url,
+			token:  tc.auth,
+		}
+		res, err := req.make()
+		assert.Nil(t, err, fmt.Sprintf("%s: unexpected error %s", tc.desc, err))
+
+		var resData twinsPageRes
+		if tc.res != nil {
+			err = json.NewDecoder(res.Body).Decode(&resData)
+			assert.Nil(t, err, fmt.Sprintf("%s: unexpected error %s", tc.desc, err))
+		}
+
+		assert.Equal(t, tc.status, res.StatusCode, fmt.Sprintf("%s: expected status code %d got %d", tc.desc, tc.status, res.StatusCode))
+		assert.ElementsMatch(t, tc.res, resData.Twins, fmt.Sprintf("%s: expected body %v got %v", tc.desc, tc.res, resData.Twins))
 	}
 }
 
 func TestRemoveTwin(t *testing.T) {
-	svc := newService(map[string]string{token: email})
+	svc := mocks.NewService(map[string]string{token: email})
 	ts := newServer(svc)
 	defer ts.Close()
 
 	def := twins.Definition{}
 	twin := twins.Twin{}
-	stw, _ := svc.AddTwin(context.Background(), token, twin, def)
+	stw, err := svc.AddTwin(context.Background(), token, twin, def)
+	require.Nil(t, err, fmt.Sprintf("unexpected error: %s", err))
 
 	cases := []struct {
 		desc   string
@@ -437,21 +624,3 @@ func TestRemoveTwin(t *testing.T) {
 		assert.Equal(t, tc.status, res.StatusCode, fmt.Sprintf("%s: expected status code %d got %d", tc.desc, tc.status, res.StatusCode))
 	}
 }
-
-type twinReq struct {
-	token      string
-	Name       string                 `json:"name,omitempty"`
-	Definition twins.Definition       `json:"definition,omitempty"`
-	Metadata   map[string]interface{} `json:"metadata,omitempty"`
-}
-
-type twinRes struct {
-	Owner       string                 `json:"owner"`
-	Name        string                 `json:"name,omitempty"`
-	ID          string                 `json:"id"`
-	Revision    int                    `json:"revision"`
-	Created     time.Time              `json:"created"`
-	Updated     time.Time              `json:"updated"`
-	Definitions []twins.Definition     `json:"definitions"`
-	Metadata    map[string]interface{} `json:"metadata,omitempty"`
-}
diff --git a/twins/doc.go b/twins/doc.go
index f850aaa5..4816cd0d 100644
--- a/twins/doc.go
+++ b/twins/doc.go
@@ -2,7 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 // Package twins contains the domain concept definitions needed to support
-// Mainflux twins service functionality. Twin is a semantic representation of a
+// Mainflux twins service functionality. Twin is a digital representation of a
 // real world data system consisting of data producers and consumers. It stores
 // the sequence of attribute based definitions of a data system and refers to a
 // time series of definition based states that store the system historical data.
diff --git a/twins/mocks/messages.go b/twins/mocks/messages.go
index 43611b33..6eba9e02 100644
--- a/twins/mocks/messages.go
+++ b/twins/mocks/messages.go
@@ -14,8 +14,8 @@ type mockBroker struct {
 	subscriptions map[string]string
 }
 
-// New returns mock message publisher.
-func New(sub map[string]string) messaging.Publisher {
+// NewBroker returns mock message publisher.
+func NewBroker(sub map[string]string) messaging.Publisher {
 	return &mockBroker{
 		subscriptions: sub,
 	}
diff --git a/twins/mocks/service.go b/twins/mocks/service.go
new file mode 100644
index 00000000..d52e4643
--- /dev/null
+++ b/twins/mocks/service.go
@@ -0,0 +1,71 @@
+package mocks
+
+import (
+	"encoding/json"
+	"time"
+
+	"github.com/mainflux/mainflux/messaging"
+	"github.com/mainflux/mainflux/twins"
+	"github.com/mainflux/mainflux/twins/uuid"
+	"github.com/mainflux/senml"
+)
+
+const (
+	publisher = "twins"
+)
+
+// NewService use mock dependencies to create real twins service
+func NewService(tokens map[string]string) twins.Service {
+	auth := NewAuthNServiceClient(tokens)
+	twinsRepo := NewTwinRepository()
+	statesRepo := NewStateRepository()
+	idp := NewIdentityProvider()
+	subs := map[string]string{"chanID": "chanID"}
+	broker := NewBroker(subs)
+	return twins.New(broker, auth, twinsRepo, statesRepo, idp, "chanID", nil)
+}
+
+// CreateDefinition creates twin definition
+func CreateDefinition(names []string, subtopics []string) twins.Definition {
+	var def twins.Definition
+	for i, v := range names {
+		id, _ := uuid.New().ID()
+		attr := twins.Attribute{
+			Name:         v,
+			Channel:      id,
+			Subtopic:     subtopics[i],
+			PersistState: true,
+		}
+		def.Attributes = append(def.Attributes, attr)
+	}
+	return def
+}
+
+// CreateSenML creates SenML record array
+func CreateSenML(n int, bn string) []senml.Record {
+	var recs []senml.Record
+	for i := 0; i < n; i++ {
+		rec := senml.Record{
+			BaseName: bn,
+			BaseTime: float64(time.Now().Unix()),
+			Time:     float64(i),
+			Value:    nil,
+		}
+		recs = append(recs, rec)
+	}
+	return recs
+}
+
+// CreateMessage creates Mainflux message using SenML record array
+func CreateMessage(attr twins.Attribute, recs []senml.Record) (*messaging.Message, error) {
+	mRecs, err := json.Marshal(recs)
+	if err != nil {
+		return nil, err
+	}
+	return &messaging.Message{
+		Channel:   attr.Channel,
+		Subtopic:  attr.Subtopic,
+		Payload:   mRecs,
+		Publisher: publisher,
+	}, nil
+}
diff --git a/twins/mocks/states.go b/twins/mocks/states.go
index f59f39f1..da747c2a 100644
--- a/twins/mocks/states.go
+++ b/twins/mocks/states.go
@@ -5,7 +5,6 @@ package mocks
 
 import (
 	"context"
-	"fmt"
 	"sort"
 	"strings"
 	"sync"
@@ -16,9 +15,8 @@ import (
 var _ twins.StateRepository = (*stateRepositoryMock)(nil)
 
 type stateRepositoryMock struct {
-	mu      sync.Mutex
-	counter uint64
-	states  map[string]twins.State
+	mu     sync.Mutex
+	states map[string]twins.State
 }
 
 // NewStateRepository creates in-memory twin repository.
@@ -53,7 +51,7 @@ func (srm *stateRepositoryMock) Count(ctx context.Context, tw twins.Twin) (int64
 	return int64(len(srm.states)), nil
 }
 
-func (srm *stateRepositoryMock) RetrieveAll(ctx context.Context, offset uint64, limit uint64, id string) (twins.StatesPage, error) {
+func (srm *stateRepositoryMock) RetrieveAll(ctx context.Context, offset uint64, limit uint64, twinID string) (twins.StatesPage, error) {
 	srm.mu.Lock()
 	defer srm.mu.Unlock()
 
@@ -63,29 +61,28 @@ func (srm *stateRepositoryMock) RetrieveAll(ctx context.Context, offset uint64,
 		return twins.StatesPage{}, nil
 	}
 
-	// This obscure way to examine map keys is enforced by the key structure in mocks/commons.go
-	prefix := fmt.Sprintf("%s-", id)
 	for k, v := range srm.states {
-		if !strings.HasPrefix(k, prefix) {
+		if (uint64)(len(items)) >= limit {
+			break
+		}
+		if !strings.HasPrefix(k, twinID) {
 			continue
 		}
 		id := uint64(v.ID)
-		if id > offset && id < limit {
+		if id >= offset && id < offset+limit {
 			items = append(items, v)
 		}
-		if (uint64)(len(items)) >= limit {
-			break
-		}
 	}
 
 	sort.SliceStable(items, func(i, j int) bool {
 		return items[i].ID < items[j].ID
 	})
 
+	total := uint64(len(srm.states))
 	page := twins.StatesPage{
 		States: items,
 		PageMetadata: twins.PageMetadata{
-			Total:  srm.counter,
+			Total:  total,
 			Offset: offset,
 			Limit:  limit,
 		},
@@ -101,11 +98,16 @@ func (srm *stateRepositoryMock) RetrieveLast(ctx context.Context, id string) (tw
 
 	items := make([]twins.State, 0)
 	for _, v := range srm.states {
-		items = append(items, v)
+		if v.TwinID == id {
+			items = append(items, v)
+		}
 	}
 	sort.SliceStable(items, func(i, j int) bool {
 		return items[i].ID < items[j].ID
 	})
 
-	return items[len(items)-1], nil
+	if len(items) > 0 {
+		return items[len(items)-1], nil
+	}
+	return twins.State{}, nil
 }
diff --git a/twins/mocks/twins.go b/twins/mocks/twins.go
index 69e4f617..585b7211 100644
--- a/twins/mocks/twins.go
+++ b/twins/mocks/twins.go
@@ -5,7 +5,6 @@ package mocks
 
 import (
 	"context"
-	"fmt"
 	"sort"
 	"strconv"
 	"strings"
@@ -17,9 +16,8 @@ import (
 var _ twins.TwinRepository = (*twinRepositoryMock)(nil)
 
 type twinRepositoryMock struct {
-	mu      sync.Mutex
-	counter uint64
-	twins   map[string]twins.Twin
+	mu    sync.Mutex
+	twins map[string]twins.Twin
 }
 
 // NewTwinRepository creates in-memory twin repository.
@@ -83,7 +81,10 @@ func (trm *twinRepositoryMock) RetrieveByAttribute(ctx context.Context, channel,
 		}
 	}
 
-	return ids, nil
+	if len(ids) > 0 {
+		return ids, nil
+	}
+	return ids, twins.ErrNotFound
 }
 
 func (trm *twinRepositoryMock) RetrieveAll(_ context.Context, owner string, offset uint64, limit uint64, name string, metadata twins.Metadata) (twins.Page, error) {
@@ -96,18 +97,19 @@ func (trm *twinRepositoryMock) RetrieveAll(_ context.Context, owner string, offs
 		return twins.Page{}, nil
 	}
 
-	// This obscure way to examine map keys is enforced by the key structure in mocks/commons.go
-	prefix := fmt.Sprintf("%s-", owner)
 	for k, v := range trm.twins {
 		if (uint64)(len(items)) >= limit {
 			break
 		}
-		if !strings.HasPrefix(k, prefix) {
+		if len(name) > 0 && v.Name != name {
+			continue
+		}
+		if !strings.HasPrefix(k, owner) {
 			continue
 		}
 		suffix := string(v.ID[len(u4Pref):])
 		id, _ := strconv.ParseUint(suffix, 10, 64)
-		if id > offset && id <= uint64(offset+limit) {
+		if id > offset && id <= offset+limit {
 			items = append(items, v)
 		}
 	}
@@ -116,10 +118,11 @@ func (trm *twinRepositoryMock) RetrieveAll(_ context.Context, owner string, offs
 		return items[i].ID < items[j].ID
 	})
 
+	total := uint64(len(trm.twins))
 	page := twins.Page{
 		Twins: items,
 		PageMetadata: twins.PageMetadata{
-			Total:  trm.counter,
+			Total:  total,
 			Offset: offset,
 			Limit:  limit,
 		},
@@ -135,6 +138,7 @@ func (trm *twinRepositoryMock) Remove(ctx context.Context, id string) error {
 	for k, v := range trm.twins {
 		if id == v.ID {
 			delete(trm.twins, k)
+			return nil
 		}
 	}
 
diff --git a/twins/service.go b/twins/service.go
index 0bff4ea9..a52b06ce 100644
--- a/twins/service.go
+++ b/twins/service.go
@@ -131,8 +131,9 @@ func (ts *twinsService) AddTwin(ctx context.Context, token string, twin Twin, de
 
 	twin.Owner = res.GetValue()
 
-	twin.Created = time.Now()
-	twin.Updated = time.Now()
+	t := time.Now()
+	twin.Created = t
+	twin.Updated = t
 
 	if def.Attributes == nil {
 		def.Attributes = []Attribute{}
@@ -324,6 +325,7 @@ func prepareState(st *State, tw *Twin, rec senml.Record, msg *messaging.Message)
 
 	if st.Payload == nil {
 		st.Payload = make(map[string]interface{})
+		st.ID = -1 // state is incremented on save -> zero-based index
 	} else {
 		for k := range st.Payload {
 			idx := findAttribute(k, def.Attributes)
@@ -356,6 +358,7 @@ func prepareState(st *State, tw *Twin, rec senml.Record, msg *messaging.Message)
 			}
 			val := findValue(rec)
 			st.Payload[attr.Name] = val
+
 			break
 		}
 	}
diff --git a/twins/service_test.go b/twins/service_test.go
index 73adee6d..ad262ac0 100644
--- a/twins/service_test.go
+++ b/twins/service_test.go
@@ -10,6 +10,7 @@ import (
 
 	"github.com/mainflux/mainflux/twins"
 	"github.com/mainflux/mainflux/twins/mocks"
+	"github.com/mainflux/senml"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -21,20 +22,18 @@ const (
 	wrongToken = "wrong-token"
 	email      = "user@example.com"
 	natsURL    = "nats://localhost:4222"
+
+	attrName1     = "temperature"
+	attrSubtopic1 = "engine"
+	attrName2     = "humidity"
+	attrSubtopic2 = "chassis"
+	attrName3     = "speed"
+	attrSubtopic3 = "wheel_2"
+	numRecs       = 100
 )
 
-func newService(tokens map[string]string) twins.Service {
-	auth := mocks.NewAuthNServiceClient(tokens)
-	twinsRepo := mocks.NewTwinRepository()
-	statesRepo := mocks.NewStateRepository()
-	idp := mocks.NewIdentityProvider()
-	subs := map[string]string{"chanID": "chanID"}
-	broker := mocks.New(subs)
-	return twins.New(broker, auth, twinsRepo, statesRepo, idp, "chanID", nil)
-}
-
 func TestAddTwin(t *testing.T) {
-	svc := newService(map[string]string{token: email})
+	svc := mocks.NewService(map[string]string{token: email})
 	twin := twins.Twin{}
 	def := twins.Definition{}
 
@@ -65,7 +64,7 @@ func TestAddTwin(t *testing.T) {
 }
 
 func TestUpdateTwin(t *testing.T) {
-	svc := newService(map[string]string{token: email})
+	svc := mocks.NewService(map[string]string{token: email})
 	twin := twins.Twin{}
 	other := twins.Twin{}
 	def := twins.Definition{}
@@ -109,7 +108,7 @@ func TestUpdateTwin(t *testing.T) {
 }
 
 func TestViewTwin(t *testing.T) {
-	svc := newService(map[string]string{token: email})
+	svc := mocks.NewService(map[string]string{token: email})
 	twin := twins.Twin{}
 	def := twins.Definition{}
 	saved, err := svc.AddTwin(context.Background(), token, twin, def)
@@ -144,7 +143,7 @@ func TestViewTwin(t *testing.T) {
 }
 
 func TestListTwins(t *testing.T) {
-	svc := newService(map[string]string{token: email})
+	svc := mocks.NewService(map[string]string{token: email})
 	twin := twins.Twin{Name: twinName, Owner: email}
 	def := twins.Definition{}
 	m := make(map[string]interface{})
@@ -202,7 +201,7 @@ func TestListTwins(t *testing.T) {
 }
 
 func TestRemoveTwin(t *testing.T) {
-	svc := newService(map[string]string{token: email})
+	svc := mocks.NewService(map[string]string{token: email})
 	twin := twins.Twin{}
 	def := twins.Definition{}
 	saved, err := svc.AddTwin(context.Background(), token, twin, def)
@@ -245,3 +244,168 @@ func TestRemoveTwin(t *testing.T) {
 		assert.Equal(t, tc.err, err, fmt.Sprintf("%s: expected %s got %s\n", tc.desc, tc.err, err))
 	}
 }
+
+func TestSaveStates(t *testing.T) {
+	svc := mocks.NewService(map[string]string{token: email})
+
+	twin := twins.Twin{Owner: email}
+	def := mocks.CreateDefinition([]string{attrName1, attrName2}, []string{attrSubtopic1, attrSubtopic2})
+	attr := def.Attributes[0]
+	attrSansTwin := mocks.CreateDefinition([]string{attrName3}, []string{attrSubtopic3}).Attributes[0]
+	tw, err := svc.AddTwin(context.Background(), token, twin, def)
+	require.Nil(t, err, fmt.Sprintf("unexpected error: %s", err))
+
+	recs := mocks.CreateSenML(numRecs, attrName1)
+	var ttlAdded uint64
+
+	cases := []struct {
+		desc string
+		recs []senml.Record
+		attr twins.Attribute
+		size uint64
+		err  error
+	}{
+		{
+			desc: "add 100 states",
+			recs: recs,
+			attr: attr,
+			size: numRecs,
+			err:  nil,
+		},
+		{
+			desc: "add 20 states",
+			recs: recs[10:30],
+			attr: attr,
+			size: 20,
+			err:  nil,
+		},
+		{
+			desc: "add 20 states for atttribute without twin",
+			recs: recs[30:50],
+			size: 0,
+			attr: attrSansTwin,
+			err:  twins.ErrNotFound,
+		},
+		{
+			desc: "use empty senml record",
+			recs: []senml.Record{},
+			attr: attr,
+			size: 0,
+			err:  nil,
+		},
+	}
+
+	for _, tc := range cases {
+		message, err := mocks.CreateMessage(tc.attr, tc.recs)
+		require.Nil(t, err, fmt.Sprintf("unexpected error: %s", err))
+
+		err = svc.SaveStates(message)
+		assert.Equal(t, tc.err, err, fmt.Sprintf("%s: expected %s got %s\n", tc.desc, tc.err, err))
+
+		ttlAdded += tc.size
+		page, err := svc.ListStates(context.TODO(), token, 0, 10, tw.ID)
+		require.Nil(t, err, fmt.Sprintf("unexpected error: %s", err))
+		assert.Equal(t, ttlAdded, page.Total, fmt.Sprintf("%s: expected %d total got %d total\n", tc.desc, ttlAdded, page.Total))
+	}
+}
+
+func TestListStates(t *testing.T) {
+	svc := mocks.NewService(map[string]string{token: email})
+
+	twin := twins.Twin{Owner: email}
+	def := mocks.CreateDefinition([]string{attrName1, attrName2}, []string{attrSubtopic1, attrSubtopic2})
+	attr := def.Attributes[0]
+	tw, err := svc.AddTwin(context.Background(), token, twin, def)
+	require.Nil(t, err, fmt.Sprintf("unexpected error: %s", err))
+
+	tw2, err := svc.AddTwin(context.Background(), token,
+		twins.Twin{Owner: email},
+		mocks.CreateDefinition([]string{attrName3}, []string{attrSubtopic3}))
+	require.Nil(t, err, fmt.Sprintf("unexpected error: %s", err))
+
+	recs := mocks.CreateSenML(numRecs, attrName1)
+	message, err := mocks.CreateMessage(attr, recs)
+	require.Nil(t, err, fmt.Sprintf("unexpected error: %s", err))
+	err = svc.SaveStates(message)
+	require.Nil(t, err, fmt.Sprintf("unexpected error: %s", err))
+
+	cases := []struct {
+		desc   string
+		id     string
+		token  string
+		offset uint64
+		limit  uint64
+		size   int
+		err    error
+	}{
+		{
+			desc:   "get a list of first 10 states",
+			id:     tw.ID,
+			token:  token,
+			offset: 0,
+			limit:  10,
+			size:   10,
+			err:    nil,
+		},
+		{
+			desc:   "get a list of last 10 states",
+			id:     tw.ID,
+			token:  token,
+			offset: numRecs - 10,
+			limit:  numRecs,
+			size:   10,
+			err:    nil,
+		},
+		{
+			desc:   "get a list of last 10 states with limit > numRecs",
+			id:     tw.ID,
+			token:  token,
+			offset: numRecs - 10,
+			limit:  numRecs + 10,
+			size:   10,
+			err:    nil,
+		},
+		{
+			desc:   "get a list of first 10 states with offset == numRecs",
+			id:     tw.ID,
+			token:  token,
+			offset: numRecs,
+			limit:  numRecs + 10,
+			size:   0,
+			err:    nil,
+		},
+		{
+			desc:   "get a list with wrong user token",
+			id:     tw.ID,
+			token:  wrongToken,
+			offset: 0,
+			limit:  10,
+			size:   0,
+			err:    twins.ErrUnauthorizedAccess,
+		},
+		{
+			desc:   "get a list with id of non-existent twin",
+			id:     "1234567890",
+			token:  token,
+			offset: 0,
+			limit:  10,
+			size:   0,
+			err:    nil,
+		},
+		{
+			desc:   "get a list with id of existing twin without states ",
+			id:     tw2.ID,
+			token:  token,
+			offset: 0,
+			limit:  10,
+			size:   0,
+			err:    nil,
+		},
+	}
+
+	for _, tc := range cases {
+		page, err := svc.ListStates(context.TODO(), tc.token, tc.offset, tc.limit, tc.id)
+		assert.Equal(t, tc.err, err, fmt.Sprintf("%s: expected %s got %s\n", tc.desc, tc.err, err))
+		assert.Equal(t, tc.size, len(page.States), fmt.Sprintf("%s: expected %d total got %d total\n", tc.desc, tc.size, len(page.States)))
+	}
+}
diff --git a/twins/twins.go b/twins/twins.go
index 4fedeaa7..1689b032 100644
--- a/twins/twins.go
+++ b/twins/twins.go
@@ -45,7 +45,6 @@ type PageMetadata struct {
 	Total  uint64
 	Offset uint64
 	Limit  uint64
-	Name   string
 }
 
 // Page contains page related metadata as well as a list of twins that