diff --git a/.gitignore b/.gitignore
index 0b4e646..8723181 100644
--- a/.gitignore
+++ b/.gitignore
@@ -13,6 +13,10 @@ _test
 *.[568vq]
 [568vq].out
 
+# IntelliJ
+*.iml
+.idea
+
 *.cgo1.go
 *.cgo2.c
 _cgo_defun.c
@@ -24,5 +28,6 @@ _testmain.go
 *.exe
 *.test
 *.prof
+*.sw[nop]
 
 mct.go
diff --git a/README.md b/README.md
index 24b673a..b10ff34 100644
--- a/README.md
+++ b/README.md
@@ -29,7 +29,7 @@ func main() {
 	// Let's get some context about these images
 	urls := []string{"http://www.clarifai.com/img/metro-north.jpg", "http://www.clarifai.com/img/metro-north.jpg"}
 	// Give it to Clarifai to run their magic
-	tag_data, err := client.Tag(urls, nil)
+	tag_data, err := client.Tag(clarifai.TagRequest{URLs: urls})
 
 	if err != nil {
 		fmt.Println(err)
diff --git a/client.go b/client.go
index 03a6627..59a5f4c 100644
--- a/client.go
+++ b/client.go
@@ -2,6 +2,7 @@
 package clarifai
 
 import (
+	"bytes"
 	"encoding/json"
 	"errors"
 	"io/ioutil"
@@ -82,20 +83,26 @@ func (client *Client) requestAccessToken() error {
 	return nil
 }
 
-func (client *Client) commonHTTPRequest(values url.Values, endpoint, verb string, retry bool) ([]byte, error) {
-	if values == nil {
-		values = url.Values{}
+func (client *Client) commonHTTPRequest(jsonBody interface{}, endpoint, verb string, retry bool) ([]byte, error) {
+	if jsonBody == nil {
+		jsonBody = struct{}{}
 	}
 
-	req, err := http.NewRequest(verb, client.buildURL(endpoint), strings.NewReader(values.Encode()))
+	body, err := json.Marshal(jsonBody)
 
 	if err != nil {
 		return nil, err
 	}
 
-	req.Header.Set("Content-Length", strconv.Itoa(len(values.Encode())))
+	req, err := http.NewRequest(verb, client.buildURL(endpoint), bytes.NewReader(body))
+
+	if err != nil {
+		return nil, err
+	}
+
+	req.Header.Set("Content-Length", strconv.Itoa(len(body)))
 	req.Header.Set("Authorization", "Bearer "+client.AccessToken)
-	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+	req.Header.Set("Content-Type", "application/json")
 
 	httpClient := &http.Client{}
 	res, err := httpClient.Do(req)
@@ -118,7 +125,7 @@ func (client *Client) commonHTTPRequest(values url.Values, endpoint, verb string
 			if err != nil {
 				return nil, err
 			}
-			return client.commonHTTPRequest(values, endpoint, verb, true)
+			return client.commonHTTPRequest(jsonBody, endpoint, verb, true)
 		}
 		return nil, errors.New("TOKEN_INVALID")
 	case 429:
diff --git a/requests.go b/requests.go
index 1ff9c65..9ad8f07 100644
--- a/requests.go
+++ b/requests.go
@@ -3,8 +3,6 @@ package clarifai
 import (
 	"encoding/json"
 	"errors"
-	"net/url"
-	"strings"
 )
 
 // InfoResp represents the expected JSON response from /info/
@@ -27,6 +25,13 @@ type InfoResp struct {
 	}
 }
 
+// TagRequest represents a JSON request for /tag/
+type TagRequest struct {
+	URLs     []string `json:"url"`
+	LocalIDs []string `json:"local_ids,omitempty"`
+	Model    string   `json:"model,omitempty"`
+}
+
 // TagResp represents the expected JSON response from /tag/
 type TagResp struct {
 	StatusCode    string `json:"status_code"`
@@ -60,13 +65,13 @@ type TagResult struct {
 
 // FeedbackForm is used to send feedback back to Clarifai
 type FeedbackForm struct {
-	DocIDs           []string
-	URLs             []string
-	AddTags          []string
-	RemoveTags       []string
-	DissimilarDocIDs []string
-	SimilarDocIDs    []string
-	SearchClick      []string
+	DocIDs           []string `json:"docids,omitempty"`
+	URLs             []string `json:"url,omitempty"`
+	AddTags          []string `json:"add_tags,omitempty"`
+	RemoveTags       []string `json:"remove_tags,omitempty"`
+	DissimilarDocIDs []string `json:"dissimilar_docids,omitempty"`
+	SimilarDocIDs    []string `json:"similar_docids,omitempty"`
+	SearchClick      []string `json:"search_click,omitempty"`
 }
 
 // FeedbackResp is the expected response from /feedback/
@@ -90,22 +95,12 @@ func (client *Client) Info() (*InfoResp, error) {
 }
 
 // Tag allows the client to request tag data on a single, or multiple photos
-func (client *Client) Tag(urls, localIDs []string) (*TagResp, error) {
-	if urls == nil {
+func (client *Client) Tag(req TagRequest) (*TagResp, error) {
+	if len(req.URLs) < 1 {
 		return nil, errors.New("Requires at least one url")
 	}
 
-	form := url.Values{}
-	for _, url := range urls {
-		form.Add("url", url)
-	}
-	if localIDs != nil {
-		for _, localID := range localIDs {
-			form.Add("local_id", localID)
-		}
-	}
-
-	res, err := client.commonHTTPRequest(form, "tag", "POST", false)
+	res, err := client.commonHTTPRequest(req, "tag", "POST", false)
 
 	if err != nil {
 		return nil, err
@@ -118,43 +113,15 @@ func (client *Client) Tag(urls, localIDs []string) (*TagResp, error) {
 }
 
 // Feedback allows the user to provide contextual feedback to Clarifai in order to improve their results
-func (client *Client) Feedback(params FeedbackForm) (*FeedbackResp, error) {
-	if params.DocIDs == nil && params.URLs == nil {
+func (client *Client) Feedback(form FeedbackForm) (*FeedbackResp, error) {
+	if form.DocIDs == nil && form.URLs == nil {
 		return nil, errors.New("Requires at least one docid or url")
 	}
 
-	if params.DocIDs != nil && params.URLs != nil {
+	if form.DocIDs != nil && form.URLs != nil {
 		return nil, errors.New("Request must provide exactly one of the following fields: {'DocIDs', 'URLs'}")
 	}
 
-	form := url.Values{}
-
-	if params.DocIDs != nil {
-		form.Add("docids", strings.Join(params.DocIDs, ","))
-	} else {
-		form.Add("url", strings.Join(params.URLs, ","))
-	}
-
-	if params.AddTags != nil {
-		form.Add("add_tags", strings.Join(params.AddTags, ","))
-	}
-
-	if params.RemoveTags != nil {
-		form.Add("remove_tags", strings.Join(params.RemoveTags, ","))
-	}
-
-	if params.DissimilarDocIDs != nil {
-		form.Add("dissimilar_docids", strings.Join(params.DissimilarDocIDs, ","))
-	}
-
-	if params.SimilarDocIDs != nil {
-		form.Add("similar_docids", strings.Join(params.SimilarDocIDs, ","))
-	}
-
-	if params.SearchClick != nil {
-		form.Add("search_click", strings.Join(params.SearchClick, ","))
-	}
-
 	res, err := client.commonHTTPRequest(form, "feedback", "POST", false)
 
 	feedbackres := new(FeedbackResp)
diff --git a/requests_test.go b/requests_test.go
index 109f0ec..53b5dd2 100644
--- a/requests_test.go
+++ b/requests_test.go
@@ -55,7 +55,7 @@ func TestTagMultiple(t *testing.T) {
 	})
 
 	urls := []string{"http://www.clarifai.com/img/metro-north.jpg", "http://www.clarifai.com/img/metro-north.jpg"}
-	_, err := client.Tag(urls, nil)
+	_, err := client.Tag(TagRequest{URLs: urls})
 
 	if err != nil {
 		t.Errorf("Tag() should not return error with valid request: %q\n", err)