diff --git a/cmd/check.go b/cmd/check.go
index 63d222e..42e676b 100644
--- a/cmd/check.go
+++ b/cmd/check.go
@@ -22,14 +22,6 @@ var checkBoxCmd = &cobra.Command{
 	Args:  BoxIdValidator,
 	RunE: func(cmd *cobra.Command, args []string) error {
 		cmd.SilenceUsage = true
-		_, err := CheckBoxes(args, defaultConf)
-		if err != nil {
-			return err
-		}
-		if shouldNotify {
-			// TODO
-		}
-
-		return nil
+		return checkAndNotify(args, defaultConf)
 	},
 }
diff --git a/cmd/jobs.go b/cmd/jobs.go
deleted file mode 100644
index b9ca5e0..0000000
--- a/cmd/jobs.go
+++ /dev/null
@@ -1,65 +0,0 @@
-package cmd
-
-import (
-	"../core"
-	log "github.com/sirupsen/logrus"
-)
-
-func CheckBoxes(boxIds []string, defaultConf *core.NotifyConfig) ([]core.CheckResult, error) {
-	log.Debug("Checking notifications for ", len(boxIds), " box(es)")
-
-	// TODO: return a map of Box: []Notification instead?
-	results := []core.CheckResult{}
-	for _, boxId := range boxIds {
-		r, err := checkBox(boxId, defaultConf)
-		if err != nil {
-			return nil, err
-		}
-
-		if r != nil {
-			results = append(results, r...)
-		}
-	}
-
-	return results, nil
-}
-
-func checkBox(boxId string, defaultConf *core.NotifyConfig) ([]core.CheckResult, error) {
-	boxLogger := log.WithFields(log.Fields{"boxId": boxId})
-	boxLogger.Info("checking box for due notifications")
-
-	// get box data
-	box, err := core.Osem.GetBox(boxId)
-	if err != nil {
-		boxLogger.Error(err)
-		return nil, err
-	}
-
-	// if box has no notify config, we use the defaultConf
-	if box.NotifyConf == nil {
-		box.NotifyConf = defaultConf
-	}
-
-	// run checks
-	results, err2 := box.RunChecks()
-	if err2 != nil {
-		boxLogger.Error("could not run checks on box: ", err2)
-		return results, err2
-	}
-
-	for _, r := range results {
-		resultLog := boxLogger.WithFields(log.Fields{
-			"status": r.Status,
-			"event":  r.Event,
-			"value":  r.Value,
-			"target": r.Target,
-		})
-		if r.Status == core.CheckOk {
-			resultLog.Debug(r)
-		} else {
-			resultLog.Warn(r)
-		}
-	}
-
-	return results, nil
-}
diff --git a/cmd/root.go b/cmd/root.go
index 0f7b34f..e744edb 100644
--- a/cmd/root.go
+++ b/cmd/root.go
@@ -2,15 +2,34 @@ package cmd
 
 import (
 	"os"
+	"strings"
 
 	log "github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
 )
 
 var rootCmd = &cobra.Command{
 	Use:  "osem_notify",
 	Long: "Run healthchecks and send notifications for boxes on opensensemap.org",
-	PersistentPreRun: func(cmd *cobra.Command, args []string) {
+	PersistentPreRunE: func(cmd *cobra.Command, args []string) error {
+		// set up config environment FIXME: cannot open / write file?!
+		viper.SetConfigType("json")
+		viper.SetConfigFile(".osem_notify")
+		viper.AddConfigPath("$HOME")
+		viper.AddConfigPath(".")
+		// // If a config file is found, read it in.
+		// if _, err := os.Stat(path.Join(os.Getenv("HOME"), ".osem_notify.yml")); err == nil {
+		// 	err := viper.ReadInConfig()
+		// 	if err != nil {
+		// 		fmt.Println("Error when reading config file:", err)
+		// 	}
+		// }
+		viper.SetEnvPrefix("osem_notify")
+		viper.SetEnvKeyReplacer(strings.NewReplacer(".", "_", "-", "_"))
+		viper.AutomaticEnv()
+
+		// set up logger
 		log.SetOutput(os.Stdout)
 		switch logLevel {
 		case "debug":
@@ -26,6 +45,8 @@ var rootCmd = &cobra.Command{
 		case "json":
 			log.SetFormatter(&log.JSONFormatter{})
 		}
+
+		return nil
 	},
 	Run: func(cmd *cobra.Command, args []string) {
 		cmd.Help()
@@ -33,17 +54,15 @@ var rootCmd = &cobra.Command{
 }
 
 var (
-	shouldNotify  bool
-	defaultConfig string
-	logLevel      string
-	logFormat     string
+	shouldNotify bool
+	logLevel     string
+	logFormat    string
 )
 
 func init() {
 	rootCmd.PersistentFlags().StringVarP(&logLevel, "log-level", "", "info", "log level, can be one of debug, info, warn, error")
 	rootCmd.PersistentFlags().StringVarP(&logFormat, "log-format", "", "plain", "log format, can be plain or json")
 	rootCmd.PersistentFlags().BoolVarP(&shouldNotify, "notify", "n", false, "if set, will send out notifications.\nOtherwise results are printed to stdout only")
-	rootCmd.PersistentFlags().StringVarP(&defaultConfig, "conf-default", "c", "", "default JSON config to use for event checking")
 }
 
 func Execute() {
diff --git a/cmd/args.go b/cmd/shared.go
similarity index 63%
rename from cmd/args.go
rename to cmd/shared.go
index d50e14a..d2e3724 100644
--- a/cmd/args.go
+++ b/cmd/shared.go
@@ -4,10 +4,38 @@ import (
 	"fmt"
 	"regexp"
 
-	"../core"
 	"github.com/spf13/cobra"
+
+	"../core"
 )
 
+/**
+ * shared functionality between watch and check
+ */
+
+// TODO: actually to be read from arg / file
+
+var defaultConf = &core.NotifyConfig{
+	Notifications: core.TransportConfig{
+		Transport: "email",
+		Options: core.EmailNotifier{
+			[]string{"test@nroo.de"},
+			"notify@nroo.de",
+		},
+	},
+	Events: []core.NotifyEvent{
+		core.NotifyEvent{
+			Type:      "measurement_age",
+			Target:    "all",
+			Threshold: "15m",
+		},
+		core.NotifyEvent{
+			Type:   "measurement_suspicious",
+			Target: "all",
+		},
+	},
+}
+
 func isValidBoxId(boxId string) bool {
 	// boxIds are UUIDs
 	r := regexp.MustCompile("^[0-9a-fA-F]{24}$")
@@ -26,17 +54,16 @@ func BoxIdValidator(cmd *cobra.Command, args []string) error {
 	return nil
 }
 
-// TODO: actually to be read from arg / file
-var defaultConf = &core.NotifyConfig{
-	Events: []core.NotifyEvent{
-		core.NotifyEvent{
-			Type:      "measurement_age",
-			Target:    "all",
-			Threshold: "15m",
-		},
-		core.NotifyEvent{
-			Type:   "measurement_suspicious",
-			Target: "all",
-		},
-	},
+func checkAndNotify(boxIds []string, defaultNotifyConf *core.NotifyConfig) error {
+	results, err := core.CheckBoxes(boxIds, defaultConf)
+	if err != nil {
+		return err
+	}
+
+	results.Log()
+
+	if shouldNotify {
+		return results.SendNotifications()
+	}
+	return nil
 }
diff --git a/cmd/watch.go b/cmd/watch.go
index d8b31fe..807eb1b 100644
--- a/cmd/watch.go
+++ b/cmd/watch.go
@@ -4,8 +4,6 @@ import (
 	"time"
 
 	"github.com/spf13/cobra"
-
-	"../core"
 )
 
 var watchInterval int
@@ -22,9 +20,6 @@ var watchCmd = &cobra.Command{
 	Aliases: []string{"serve"},
 	Short:   "Watch boxes for events at an interval",
 	Long:    "Watch boxes for events at an interval",
-	PersistentPreRun: func(cmd *cobra.Command, args []string) {
-		ticker = time.NewTicker(time.Duration(watchInterval) * time.Second).C
-	},
 }
 
 var watchBoxesCmd = &cobra.Command{
@@ -32,47 +27,21 @@ var watchBoxesCmd = &cobra.Command{
 	Short: "watch a list of box IDs for events",
 	Long:  "specify box IDs to watch them for events",
 	Args:  BoxIdValidator,
+	PreRun: func(cmd *cobra.Command, args []string) {
+		ticker = time.NewTicker(time.Duration(watchInterval) * time.Second).C
+	},
 	RunE: func(cmd *cobra.Command, args []string) error {
 		cmd.SilenceUsage = true
-		exec := func() error {
-			results, err := CheckBoxes(args, defaultConf)
-			if err != nil {
-				return err
-			}
-
-			results, err = filterFromCache(results)
-			if err != nil {
-				return err
-			}
-
-			if shouldNotify {
-				// TODO
-			}
-			return nil
-		}
-
-		err := exec()
+		err := checkAndNotify(args, defaultConf)
 		if err != nil {
 			return err
 		}
 		for {
 			<-ticker
-			err = exec()
+			err = checkAndNotify(args, defaultConf)
 			if err != nil {
 				return err
 			}
 		}
 	},
 }
-
-func filterFromCache(results []core.CheckResult) ([]core.CheckResult, error) {
-	// get results from cache. they are indexed by ______
-
-	// filter, so that only changed result.Status remain
-
-	// extract additional results with Status ERR from cache with time.Since(lastNotifyDate) > thresh
-
-	// upate cache set lastNotifyDate to Now()
-
-	return results, nil
-}
diff --git a/core/Box.go b/core/Box.go
index 4aa3c8d..c8d96fe 100644
--- a/core/Box.go
+++ b/core/Box.go
@@ -8,14 +8,23 @@ import (
 
 const (
 	CheckOk                       = "OK"
-	CheckErr                      = "ERROR"
-	eventMeasurementAge           = "measurement_age"        // errors if age of last measurement is higher than a duration
-	eventMeasurementValMin        = "measurement_min"        // errors if value of last measurement is lower than threshold
-	eventMeasurementValMax        = "measurement_max"        // errors if value of last measurement is higher than threshold
-	eventMeasurementValSuspicious = "measurement_suspicious" // checks value of last measurement against a blacklist of values
-	eventTargetAll                = "all"                    // if event.Target is this value, all sensors will be checked
+	CheckErr                      = "FAILED"
+	eventMeasurementAge           = "measurement_age"
+	eventMeasurementValMin        = "measurement_min"
+	eventMeasurementValMax        = "measurement_max"
+	eventMeasurementValSuspicious = "measurement_suspicious"
+	eventTargetAll                = "all" // if event.Target is this value, all sensors will be checked
 )
 
+type checkType = struct{ description string }
+
+var checkTypes = map[string]checkType{
+	eventMeasurementAge:           checkType{"No measurement from %s since %s"},
+	eventMeasurementValMin:        checkType{"Sensor %s reads low value of %s"},
+	eventMeasurementValMax:        checkType{"Sensor %s reads high value of %s"},
+	eventMeasurementValSuspicious: checkType{"Sensor %s reads presumably faulty value of %s"},
+}
+
 type SuspiciousValue struct {
 	sensor string
 	val    float64
@@ -28,29 +37,25 @@ var suspiciousVals = map[SuspiciousValue]bool{
 	SuspiciousValue{sensor: "SDS 011", val: 0.0}: true,
 }
 
-type CheckResult struct {
-	Status string
-	Event  string
-	Target string
-	Value  string
-}
-
-func (r CheckResult) String() string {
-	return fmt.Sprintf("check %s on sensor %s: %s with value %s\n", r.Event, r.Target, r.Status, r.Value)
-}
-
 type NotifyEvent struct {
 	Type      string `json:"type"`
 	Target    string `json:"target"`
 	Threshold string `json:"threshold"`
 }
 
+type TransportConfig struct {
+	Transport string      `json:"transport"`
+	Options   interface{} `json:"options"`
+}
+
 type NotifyConfig struct {
-	Events []NotifyEvent `json:"events"`
+	Notifications TransportConfig `json:"notifications"`
+	Events        []NotifyEvent   `json:"events"`
 }
 
 type Box struct {
 	Id      string `json:"_id"`
+	Name    string `json:"name"`
 	Sensors []struct {
 		Id              string `json:"_id"`
 		Type            string `json:"sensorType"`
@@ -59,7 +64,7 @@ type Box struct {
 			Date  time.Time `json:"createdAt"`
 		} `json:"lastMeasurement"`
 	} `json:"sensors"`
-	NotifyConf *NotifyConfig `json:"notify"`
+	NotifyConf *NotifyConfig `json:"healthcheck"`
 }
 
 func (box Box) RunChecks() ([]CheckResult, error) {
@@ -89,10 +94,11 @@ func (box Box) RunChecks() ([]CheckResult, error) {
 					}
 
 					results = append(results, CheckResult{
-						Event:  event.Type,
-						Target: s.Id,
-						Value:  s.LastMeasurement.Date.String(),
-						Status: status,
+						Threshold: event.Threshold,
+						Event:     event.Type,
+						Target:    s.Id,
+						Value:     s.LastMeasurement.Date.String(),
+						Status:    status,
 					})
 
 				case eventMeasurementValMin, eventMeasurementValMax:
@@ -111,10 +117,11 @@ func (box Box) RunChecks() ([]CheckResult, error) {
 					}
 
 					results = append(results, CheckResult{
-						Event:  event.Type,
-						Target: s.Id,
-						Value:  s.LastMeasurement.Value,
-						Status: status,
+						Threshold: event.Threshold,
+						Event:     event.Type,
+						Target:    s.Id,
+						Value:     s.LastMeasurement.Value,
+						Status:    status,
 					})
 
 				case eventMeasurementValSuspicious:
@@ -132,10 +139,11 @@ func (box Box) RunChecks() ([]CheckResult, error) {
 					}
 
 					results = append(results, CheckResult{
-						Event:  event.Type,
-						Target: s.Id,
-						Value:  s.LastMeasurement.Value,
-						Status: status,
+						Threshold: event.Threshold,
+						Event:     event.Type,
+						Target:    s.Id,
+						Value:     s.LastMeasurement.Value,
+						Status:    status,
 					})
 				}
 			}
@@ -144,3 +152,17 @@ func (box Box) RunChecks() ([]CheckResult, error) {
 	// must return ALL events to enable Notifier to clear previous notifications
 	return results, nil
 }
+
+func (box Box) GetNotifier() (AbstractNotifier, error) {
+	transport := box.NotifyConf.Notifications.Transport
+	if transport == "" {
+		return nil, fmt.Errorf("No notification transport provided")
+	}
+
+	notifier := notifiers[transport]
+	if notifier == nil {
+		return nil, fmt.Errorf("%s is not a supported notification transport", transport)
+	}
+
+	return notifier.New(box.NotifyConf.Notifications.Options)
+}
diff --git a/core/BoxCheckResults.go b/core/BoxCheckResults.go
new file mode 100644
index 0000000..41642ae
--- /dev/null
+++ b/core/BoxCheckResults.go
@@ -0,0 +1,182 @@
+package core
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"fmt"
+
+	log "github.com/sirupsen/logrus"
+	"github.com/spf13/viper"
+)
+
+type CheckResult struct {
+	Status    string
+	Event     string
+	Target    string
+	Value     string
+	Threshold string
+}
+
+func (r CheckResult) EventID() string {
+	s := fmt.Sprintf("%s%s%s", r.Event, r.Target, r.Threshold)
+	hasher := sha256.New()
+	hasher.Write([]byte(s))
+	return hex.EncodeToString(hasher.Sum(nil))
+}
+
+func (r CheckResult) String() string {
+	if r.Status == CheckOk {
+		return fmt.Sprintf("%s %s (on sensor %s with value %s)\n", r.Event, r.Status, r.Target, r.Value)
+	} else {
+		return fmt.Sprintf("%s: "+checkTypes[r.Event].description+"\n", r.Status, r.Target, r.Value)
+	}
+}
+
+type BoxCheckResults map[*Box][]CheckResult
+
+func (results BoxCheckResults) Size() int {
+	size := 0
+	for _, boxResults := range results {
+		size += len(boxResults)
+	}
+	return size
+}
+
+func (results BoxCheckResults) Log() {
+	for box, boxResults := range results {
+		boxLog := log.WithFields(log.Fields{
+			"boxId": box.Id,
+		})
+		countErr := 0
+		for _, r := range boxResults {
+			resultLog := boxLog.WithFields(log.Fields{
+				"status": r.Status,
+				"event":  r.Event,
+				"value":  r.Value,
+				"target": r.Target,
+			})
+			if r.Status == CheckOk {
+				resultLog.Debugf("%s: %s", box.Name, r)
+			} else {
+				resultLog.Warnf("%s: %s", box.Name, r)
+				countErr++
+			}
+		}
+		if countErr == 0 {
+			boxLog.Infof("%s: all is fine!", box.Name)
+		}
+	}
+}
+
+func (results BoxCheckResults) SendNotifications() error {
+	results = results.FilterChangedFromCache(false)
+
+	n := results.Size()
+	if n == 0 {
+		log.Info("No notifications due.")
+		return nil
+	} else {
+		log.Infof("Notifying for %v checks turned bad in total...", results.Size())
+	}
+
+	for box, resultsDue := range results {
+		if len(resultsDue) == 0 {
+			continue
+		}
+
+		transport := box.NotifyConf.Notifications.Transport
+		notifyLog := log.WithFields(log.Fields{
+			"boxId":     box.Id,
+			"transport": transport,
+		})
+
+		notifier, err2 := box.GetNotifier()
+		if err2 != nil {
+			notifyLog.Error(err2)
+			return err2
+		}
+		notification := notifier.ComposeNotification(box, resultsDue)
+		err3 := notifier.Submit(notification)
+		if err3 != nil {
+			notifyLog.Error(err3)
+			return err3
+		}
+		notifyLog.Infof("Sent notification for %s via %s with %v new issues", box.Name, transport, len(resultsDue))
+	}
+
+	return nil
+}
+
+func (results BoxCheckResults) FilterChangedFromCache(keepOk bool) BoxCheckResults {
+	remaining := BoxCheckResults{}
+
+	for box, boxResults := range results {
+		// get results from cache. they are indexed by an event ID per boxId
+		// filter, so that only changed result.Status remain
+		remaining[box] = []CheckResult{}
+		for _, result := range boxResults {
+			cached := viper.GetStringMap(fmt.Sprintf("watchcache.%s.%s", box.Id, result.EventID()))
+			if result.Status != cached["laststatus"] {
+				if result.Status != CheckOk || keepOk {
+					remaining[box] = append(remaining[box], result)
+				}
+			}
+		}
+
+		// TODO: reminder functionality: extract additional results with Status ERR
+		// from cache with time.Since(lastNotifyDate) > remindAfter.
+		// would require to serialize the full result..
+	}
+
+	// upate cache, setting lastNotifyDate to Now()
+	for box, boxResults := range results {
+		for _, result := range boxResults {
+			// FIXME: somehow this is not persisted?
+			key := fmt.Sprintf("watchcache.%s.%s", box.Id, result.EventID())
+			viper.Set(key+".laststatus", result.Status)
+		}
+	}
+
+	return remaining
+}
+
+func CheckBoxes(boxIds []string, defaultConf *NotifyConfig) (BoxCheckResults, error) {
+	log.Debug("Checking notifications for ", len(boxIds), " box(es)")
+
+	results := BoxCheckResults{}
+	for _, boxId := range boxIds {
+		box, res, err := checkBox(boxId, defaultConf)
+		if err != nil {
+			return nil, err
+		}
+		results[box] = res
+	}
+
+	return results, nil
+}
+
+func checkBox(boxId string, defaultConf *NotifyConfig) (*Box, []CheckResult, error) {
+	boxLogger := log.WithFields(log.Fields{"boxId": boxId})
+	boxLogger.Info("checking box for events")
+
+	// get box data
+	box, err := Osem.GetBox(boxId)
+	if err != nil {
+		boxLogger.Error(err)
+		return nil, nil, err
+	}
+
+	// if box has no notify config, we use the defaultConf
+	if box.NotifyConf == nil {
+		box.NotifyConf = defaultConf
+	}
+
+	// run checks
+	results, err2 := box.RunChecks()
+	if err2 != nil {
+		boxLogger.Error("could not run checks on box: ", err2)
+		return box, results, err2
+	}
+
+	return box, results, nil
+}
diff --git a/core/OsemClient.go b/core/OsemClient.go
index b5425e2..c8bae5e 100644
--- a/core/OsemClient.go
+++ b/core/OsemClient.go
@@ -22,10 +22,10 @@ func NewOsemClient(client *http.Client) *OsemClient {
 	}
 }
 
-func (client *OsemClient) GetBox(boxId string) (Box, error) {
-	box := Box{}
-	fail := OsemError{}
-	client.sling.New().Path("boxes/").Path(boxId).Receive(&box, &fail)
+func (client *OsemClient) GetBox(boxId string) (*Box, error) {
+	box := &Box{}
+	fail := &OsemError{}
+	client.sling.New().Path("boxes/").Path(boxId).Receive(box, fail)
 	if fail.Message != "" {
 		return box, errors.New("could not fetch box: " + fail.Message)
 	}
diff --git a/core/notifiers.go b/core/notifiers.go
index 0186055..a0abe94 100644
--- a/core/notifiers.go
+++ b/core/notifiers.go
@@ -1,14 +1,81 @@
 package core
 
+import (
+	"errors"
+	"fmt"
+	"net/smtp"
+	"strings"
+	"time"
+)
+
+var notifiers = map[string]AbstractNotifier{
+	"email": EmailNotifier{},
+}
+
 type AbstractNotifier interface {
-	GetName() string
-	SetupTransport(config interface{}) error
-	AddNotifications(notifications []Notification) error
-	SendNotifications() error
+	New(config interface{}) (AbstractNotifier, error)
+	ComposeNotification(box *Box, checks []CheckResult) Notification
+	Submit(notification Notification) error
 }
 
 type Notification struct {
+	body    string
+	subject string
+}
+
+type EmailNotifier struct {
+	Recipients  []string
+	FromAddress string
+}
+
+func (n EmailNotifier) New(config interface{}) (AbstractNotifier, error) {
+	res, ok := config.(EmailNotifier)
+
+	if !ok || res.Recipients == nil || res.FromAddress == "" {
+		return nil, errors.New("Invalid EmailNotifier options")
+	}
+
+	return EmailNotifier{
+		Recipients:  res.Recipients,
+		FromAddress: res.FromAddress,
+	}, nil
+}
+
+func (n EmailNotifier) ComposeNotification(box *Box, checks []CheckResult) Notification {
+	resultTexts := []string{}
+	for _, check := range checks {
+		resultTexts = append(resultTexts, check.String())
+	}
+
+	return Notification{
+		subject: fmt.Sprintf("Issues with your box \"%s\" on opensensemap.org!", box.Name),
+		body: fmt.Sprintf("A check at %s identified the following issue(s) with your box %s:\n\n%s\n\nYou may visit https://opensensemap.org/explore/%s for more details.\n\n--\nSent automatically by osem_notify (https://github.com/noerw/osem_notify)",
+			time.Now().Round(time.Minute), box.Name, strings.Join(resultTexts, "\n"), box.Id),
+	}
 }
 
-// TODO: multiple transports? one transport per event? (??)
-type SlackConfig struct{}
+func (n EmailNotifier) Submit(notification Notification) error {
+	// Set up authentication information. TODO: load from config
+	auth := smtp.PlainAuth(
+		"",
+		"USERNAME",
+		"PASSWORD",
+		"SERVER",
+	)
+
+	fromAddress := "EXAMPLE@EXAMPLE.COM"
+	from := fmt.Sprintf("openSenseMap Notifier <%s>", fromAddress)
+	body := fmt.Sprintf("From: %s\nSubject: %s\nContent-Type: text/plain; charset=\"utf-8\"\n\n%s", from, notification.subject, notification.body)
+
+	// Connect to the server, authenticate, set the sender and recipient,
+	// and send the email all in one step.
+	err := smtp.SendMail(
+		"smtp.gmx.de:25",
+		auth,
+		fromAddress,
+		n.Recipients,
+		[]byte(body),
+	)
+
+	return err
+}