diff --git a/kvdb/kvdb.go b/kvdb/kvdb.go
new file mode 100644
index 0000000..f7704bd
--- /dev/null
+++ b/kvdb/kvdb.go
@@ -0,0 +1,131 @@
+package kvdb
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+)
+
+type KVDB struct {
+	Prefix string
+	Ext    string
+}
+
+func (kv *KVDB) Load(
+	keyif interface{},
+	typ ...interface{},
+) (value interface{}, ok bool, err error) {
+	key, _ := keyif.(string)
+	if "" == key || strings.Contains(key, "..") || strings.ContainsAny(key, "$#!:| \n") {
+		return nil, false, nil
+	}
+
+	userFile := filepath.Join(kv.Prefix, key+"."+kv.Ext)
+	fmt.Println("Debug user file:", userFile)
+	b, err := ioutil.ReadFile(userFile)
+	if nil != err {
+		if os.IsNotExist(err) {
+			return nil, false, nil
+		}
+		fmt.Println("kvdb debug read:", err)
+		return nil, false, errors.New("database read failed")
+	}
+
+	ok = true
+	value = b
+	if 1 == len(typ) {
+		err := json.Unmarshal(b, typ[0])
+		if nil != err {
+			return nil, false, err
+		}
+		value = typ[0]
+	} else if len(b) > 0 && '"' == b[0] {
+		var str string
+		err := json.Unmarshal(b, &str)
+		if nil == err {
+			value = str
+		}
+	}
+
+	return value, ok, nil
+}
+
+func (kv *KVDB) Store(keyif interface{}, value interface{}) (err error) {
+	key, _ := keyif.(string)
+	if "" == key || strings.Contains(key, "..") || strings.ContainsAny(key, "$#! \n") {
+		return errors.New("invalid key name")
+	}
+
+	keypath := filepath.Join(kv.Prefix, key+"."+kv.Ext)
+	f, err := os.Open(keypath)
+	if nil == err {
+		s, err := f.Stat()
+		if nil != err {
+			// if we can open, we should be able to stat
+			return errors.New("database connection failure")
+		}
+		ts := strconv.FormatInt(s.ModTime().Unix(), 10)
+		bakpath := filepath.Join(kv.Prefix, key+"."+ts+"."+kv.Ext)
+		if err := os.Rename(keypath, bakpath); nil != err {
+			// keep the old record as a backup
+			return errors.New("database write failure")
+		}
+	}
+
+	var b []byte
+	switch v := value.(type) {
+	case []byte:
+		b = v
+	case string:
+		b, _ = json.Marshal(v)
+	default:
+		fmt.Println("kvdb: not []byte or string:", v)
+		jsonb, err := json.Marshal(v)
+		if nil != err {
+			return err
+		}
+		b = jsonb
+	}
+
+	if err := ioutil.WriteFile(
+		keypath,
+		b,
+		os.FileMode(0600),
+	); nil != err {
+		fmt.Println("write failure:", err)
+		return errors.New("database write failed")
+	}
+
+	return nil
+}
+
+func (kv *KVDB) Delete(keyif interface{}) (err error) {
+	key, _ := keyif.(string)
+	if "" == key || strings.Contains(key, "..") || strings.ContainsAny(key, "$#! \n") {
+		return errors.New("invalid key name")
+	}
+
+	keypath := filepath.Join(kv.Prefix, key+"."+kv.Ext)
+	f, err := os.Open(keypath)
+	if nil == err {
+		s, err := f.Stat()
+		if nil != err {
+			return errors.New("database connection failure")
+		}
+		ts := strconv.FormatInt(s.ModTime().Unix(), 64)
+		if err := os.Rename(keypath, filepath.Join(kv.Prefix, key+"."+ts+"."+kv.Ext)); nil != err {
+			return errors.New("database connection failure")
+		}
+	}
+
+	return nil
+}
+
+func (kv *KVDB) Vacuum() (err error) {
+	return nil
+}
diff --git a/kvdb/kvdb_test.go b/kvdb/kvdb_test.go
new file mode 100644
index 0000000..5328bd3
--- /dev/null
+++ b/kvdb/kvdb_test.go
@@ -0,0 +1,63 @@
+package kvdb
+
+import (
+	"strings"
+	"testing"
+)
+
+type TestEntry struct {
+	Email    string   `json:"email"`
+	Subjects []string `json:"subjects"`
+}
+
+var email = "john@example.com"
+var sub = "id123"
+var dbPrefix = "../testdb"
+var testKV = &KVDB{
+	Prefix: dbPrefix + "/test-entries",
+	Ext:    "eml.json",
+}
+
+func TestStore(t *testing.T) {
+	entry := &TestEntry{
+		Email:    email,
+		Subjects: []string{sub},
+	}
+
+	if err := testKV.Store(email, entry); nil != err {
+		t.Fatal(err)
+		return
+	}
+
+	value, ok, err := testKV.Load(email, &(TestEntry{}))
+	if nil != err {
+		t.Fatal(err)
+		return
+	}
+	if !ok {
+		t.Fatal("test entry not found")
+	}
+
+	v, ok := value.(*TestEntry)
+	if !ok {
+		t.Fatal("test entry not of type TestEntry")
+	}
+
+	if email != v.Email || sub != strings.Join(v.Subjects, ",") {
+		t.Fatalf("value: %#v", v)
+	}
+}
+
+func TestNoExist(t *testing.T) {
+	value, ok, err := testKV.Load("not"+email, &(TestEntry{}))
+	if nil != err {
+		t.Fatal(err)
+		return
+	}
+	if ok {
+		t.Fatal("found entry that doesn't exist")
+	}
+	if value != nil {
+		t.Fatal("had value for entry that doesn't exist")
+	}
+}