diff --git a/cmd/tests.sh b/cmd/tests.sh
index 27caf27..2f0a909 100755
--- a/cmd/tests.sh
+++ b/cmd/tests.sh
@@ -348,6 +348,11 @@ tw --session Offline_Twatter search "from:michaelmalice constitution"
 test $(sqlite3 twitter.db "select count(*) from tweets where user_id = 44067298 and text like '%constitution%'") -gt "30"  # Not sure exactly how many
 
 
+# Test liking and unliking
+tw --session Offline_Twatter like_tweet https://twitter.com/elonmusk/status/1589023388676554753
+tw --session Offline_Twatter unlike_tweet https://twitter.com/elonmusk/status/1589023388676554753
+
+
 # TODO: Maybe this file should be broken up into multiple test scripts
 
 echo -e "\033[32mAll tests passed.  Finished successfully.\033[0m"
diff --git a/cmd/twitter/help_message.txt b/cmd/twitter/help_message.txt
index f8a3f2d..15af4f4 100644
--- a/cmd/twitter/help_message.txt
+++ b/cmd/twitter/help_message.txt
@@ -60,7 +60,12 @@ This application downloads tweets from twitter and saves them in a SQLite databa
 
     search
           <TARGET> is the search query.  Should be wrapped in quotes if it has spaces.
+          (Requires authentication)
 
+    like_tweet
+    unlike_tweet
+          "Like" or un-"like" the tweet indicated by <TARGET>.
+          (Requires authentication)
 <flags>:
     -h, --help
           Print this message, then exit.
diff --git a/cmd/twitter/main.go b/cmd/twitter/main.go
index 6404ac5..ff8d949 100644
--- a/cmd/twitter/main.go
+++ b/cmd/twitter/main.go
@@ -144,6 +144,10 @@ func main() {
 		follow_user(target, false)
 	case "list_followed":
 		list_followed()
+	case "like_tweet":
+		like_tweet(target)
+	case "unlike_tweet":
+		unlike_tweet(target)
 	default:
 		die(fmt.Sprintf("Invalid operation: %s", operation), true, 3)
 	}
@@ -318,6 +322,30 @@ func follow_user(handle string, is_followed bool) {
 	}
 }
 
+func unlike_tweet(tweet_identifier string) {
+	tweet_id, err := extract_id_from(tweet_identifier)
+	if err != nil {
+		die(err.Error(), false, -1)
+	}
+	err = scraper.UnlikeTweet(tweet_id)
+	if err != nil {
+		die(err.Error(), false, -10)
+	}
+	happy_exit("Unliked the tweet.")
+}
+
+func like_tweet(tweet_identifier string) {
+	tweet_id, err := extract_id_from(tweet_identifier)
+	if err != nil {
+		die(err.Error(), false, -1)
+	}
+	err = scraper.LikeTweet(tweet_id)
+	if err != nil {
+		die(err.Error(), false, -10)
+	}
+	happy_exit("Liked the tweet.")
+}
+
 func list_followed() {
 	for _, handle := range profile.GetAllFollowedUsers() {
 		fmt.Println(handle)
diff --git a/scraper/api_request_utils.go b/scraper/api_request_utils.go
index 78381fc..5aac198 100644
--- a/scraper/api_request_utils.go
+++ b/scraper/api_request_utils.go
@@ -218,6 +218,12 @@ func (api *API) do_http_POST(url string, body string, result interface{}) error
 
 	api.add_authentication_headers(req)
 
+	log.Debug(fmt.Sprintf("POST: %s\n", req.URL.String()))
+	for header := range req.Header {
+		log.Debug(fmt.Sprintf("    %s: %s\n", header, req.Header.Get(header)))
+	}
+	log.Debug("    " + body)
+
 	resp, err := api.Client.Do(req)
 	if err != nil {
 		return fmt.Errorf("Error executing HTTP POST request:\n  %w", err)
diff --git a/scraper/api_types_posting.go b/scraper/api_types_posting.go
new file mode 100644
index 0000000..301fcd6
--- /dev/null
+++ b/scraper/api_types_posting.go
@@ -0,0 +1,89 @@
+package scraper
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+
+	log "github.com/sirupsen/logrus"
+)
+
+var AlreadyLikedThisTweet error = errors.New("already liked this tweet")
+var HaventLikedThisTweet error = errors.New("Haven't liked this tweet")
+
+func (api API) LikeTweet(id TweetID) error {
+	type LikeResponse struct {
+		Data struct {
+			FavoriteTweet string `json:"favorite_tweet"`
+		} `json:"data"`
+		Errors []struct {
+			Message string `json:"message"`
+			Code    int    `json:"code"`
+			Kind    string `json:"kind"`
+			Name    string `json:"name"`
+		} `json:"errors"`
+	}
+	var result LikeResponse
+	err := api.do_http_POST(
+		"https://twitter.com/i/api/graphql/lI07N6Otwv1PhnEgXILM7A/FavoriteTweet",
+		"{\"variables\":{\"tweet_id\":\""+fmt.Sprint(id)+"\"},\"queryId\":\"lI07N6Otwv1PhnEgXILM7A\"}",
+		&result,
+	)
+	if err != nil {
+		return fmt.Errorf("Error executing the HTTP POST request:\n  %w", err)
+	}
+	if len(result.Errors) > 0 {
+		if strings.Contains(result.Errors[0].Message, "has already favorited tweet") {
+			return AlreadyLikedThisTweet
+		}
+	}
+	if result.Data.FavoriteTweet != "Done" {
+		panic(fmt.Sprintf("Dunno why but it failed with value %q", result.Data.FavoriteTweet))
+	}
+	return nil
+}
+
+func (api API) UnlikeTweet(id TweetID) error {
+	type UnlikeResponse struct {
+		Data struct {
+			UnfavoriteTweet string `json:"unfavorite_tweet"`
+		} `json:"data"`
+		Errors []struct {
+			Message string `json:"message"`
+			Code    int    `json:"code"`
+			Kind    string `json:"kind"`
+			Name    string `json:"name"`
+		} `json:"errors"`
+	}
+	var result UnlikeResponse
+	err := api.do_http_POST(
+		"https://twitter.com/i/api/graphql/ZYKSe-w7KEslx3JhSIk5LA/UnfavoriteTweet",
+		"{\"variables\":{\"tweet_id\":\""+fmt.Sprint(id)+"\"},\"queryId\":\"ZYKSe-w7KEslx3JhSIk5LA\"}",
+		&result,
+	)
+	if err != nil {
+		return fmt.Errorf("Error executing the HTTP POST request:\n  %w", err)
+	}
+	if len(result.Errors) > 0 {
+		if strings.Contains(result.Errors[0].Message, "not found in actor's") {
+			return HaventLikedThisTweet
+		}
+	}
+	if result.Data.UnfavoriteTweet != "Done" {
+		panic(fmt.Sprintf("Dunno why but it failed with value %q", result.Data.UnfavoriteTweet))
+	}
+	return nil
+}
+
+func LikeTweet(id TweetID) error {
+	if !the_api.IsAuthenticated {
+		log.Fatalf("Must be authenticated!")
+	}
+	return the_api.LikeTweet(id)
+}
+func UnlikeTweet(id TweetID) error {
+	if !the_api.IsAuthenticated {
+		log.Fatalf("Must be authenticated!")
+	}
+	return the_api.UnlikeTweet(id)
+}