diff --git a/gallery_dl/extractor/2chan.py b/gallery_dl/extractor/2chan.py
index b78d08df..9927b5ab 100644
--- a/gallery_dl/extractor/2chan.py
+++ b/gallery_dl/extractor/2chan.py
@@ -19,7 +19,6 @@ class _2chanThreadExtractor(Extractor):
     directory_fmt = ("{category}", "{board_name}", "{thread}")
     filename_fmt = "{tim}.{extension}"
     archive_fmt = "{board}_{thread}_{tim}"
-    url_fmt = "https://{server}.2chan.net/{board}/src/{filename}"
     pattern = r"(?:https?://)?([\w-]+)\.2chan\.net/([^/?#]+)/res/(\d+)"
     example = "https://dec.2chan.net/12/res/12345.htm"
 
@@ -37,7 +36,8 @@ class _2chanThreadExtractor(Extractor):
             if "filename" not in post:
                 continue
             post.update(data)
-            url = self.url_fmt.format_map(post)
+            url = (f"https://{post['server']}.2chan.net"
+                   f"/{post['board']}/src/{post['filename']}")
             yield Message.Url, url, post
 
     def metadata(self, page):
diff --git a/gallery_dl/extractor/common.py b/gallery_dl/extractor/common.py
index 533fe422..c646c145 100644
--- a/gallery_dl/extractor/common.py
+++ b/gallery_dl/extractor/common.py
@@ -417,7 +417,7 @@ class Extractor():
 
             for key, value in HEADERS[browser]:
                 if value and "{}" in value:
-                    headers[key] = value.format(platform)
+                    headers[key] = value.replace("{}", platform)
                 else:
                     headers[key] = value
 
diff --git a/gallery_dl/extractor/deviantart.py b/gallery_dl/extractor/deviantart.py
index 037b981b..f30b4346 100644
--- a/gallery_dl/extractor/deviantart.py
+++ b/gallery_dl/extractor/deviantart.py
@@ -322,7 +322,7 @@ class DeviantartExtractor(Extractor):
             header = HEADER_TEMPLATE.format(
                 title=title,
                 url=url,
-                userurl="{}/{}/".format(self.root, urlname),
+                userurl=f"{self.root}/{urlname}/",
                 username=username,
                 date=deviation["date"],
             )
@@ -747,13 +747,10 @@ x2="45.4107524%" y2="71.4898596%" id="app-root-3">\
 
         deviation["_fallback"] = (content["src"],)
         deviation["is_original"] = True
+        pl = binascii.b2a_base64(payload).rstrip(b'=\n').decode()
         content["src"] = (
-            "{}?token=eyJ0eXAiOiJKV1QiLCJhbGciOiJub25lIn0.{}.".format(
-                url,
-                #  base64 of 'header' is precomputed as 'eyJ0eX...'
-                #  binascii.b2a_base64(header).rstrip(b"=\n").decode(),
-                binascii.b2a_base64(payload).rstrip(b"=\n").decode())
-        )
+            # base64 of 'header' is precomputed as 'eyJ0eX...'
+            f"{url}?token=eyJ0eXAiOiJKV1QiLCJhbGciOiJub25lIn0.{pl}.")
 
     def _extract_comments(self, target_id, target_type="deviation"):
         results = None
diff --git a/gallery_dl/extractor/discord.py b/gallery_dl/extractor/discord.py
index c8b01c85..216e4866 100644
--- a/gallery_dl/extractor/discord.py
+++ b/gallery_dl/extractor/discord.py
@@ -22,8 +22,6 @@ class DiscordExtractor(Extractor):
     filename_fmt = "{message_id}_{num:>02}_{filename}.{extension}"
     archive_fmt = "{message_id}_{num}"
 
-    cdn_fmt = "https://cdn.discordapp.com/{}/{}/{}.png?size=4096"
-
     server_metadata = {}
     server_channels_metadata = {}
 
@@ -86,11 +84,10 @@ class DiscordExtractor(Extractor):
             ):
                 if message["author"].get(icon_type):
                     message_metadata["author_files"].append({
-                        "url": self.cdn_fmt.format(
-                            icon_path,
-                            message_metadata["author_id"],
-                            message["author"][icon_type]
-                        ),
+                        "url": (f"https://cdn.discordapp.com/{icon_path}/"
+                                f"{message_metadata['author_id']}/"
+                                f"{message['author'][icon_type]}.png"
+                                f"?size=4096"),
                         "filename": icon_type,
                         "extension": "png",
                     })
@@ -222,11 +219,9 @@ class DiscordExtractor(Extractor):
         ):
             if server.get(icon_type):
                 self.server_metadata["server_files"].append({
-                    "url": self.cdn_fmt.format(
-                        icon_path,
-                        self.server_metadata["server_id"],
-                        server[icon_type]
-                    ),
+                    "url": (f"https://cdn.discordapp.com/{icon_path}/"
+                            f"{self.server_metadata['server_id']}/"
+                            f"{server[icon_type]}.png?size=4096"),
                     "filename": icon_type,
                     "extension": "png",
                 })
diff --git a/gallery_dl/extractor/facebook.py b/gallery_dl/extractor/facebook.py
index 5f697bc5..18190e38 100644
--- a/gallery_dl/extractor/facebook.py
+++ b/gallery_dl/extractor/facebook.py
@@ -20,9 +20,6 @@ class FacebookExtractor(Extractor):
     filename_fmt = "{id}.{extension}"
     archive_fmt = "{id}.{extension}"
 
-    set_url_fmt = root + "/media/set/?set={set_id}"
-    photo_url_fmt = root + "/photo/?fbid={photo_id}&set={set_id}"
-
     def _init(self):
         headers = self.session.headers
         headers["Accept"] = (
@@ -242,9 +239,7 @@ class FacebookExtractor(Extractor):
 
         while i < len(all_photo_ids):
             photo_id = all_photo_ids[i]
-            photo_url = self.photo_url_fmt.format(
-                photo_id=photo_id, set_id=set_id
-            )
+            photo_url = f"{self.root}/photo/?fbid={photo_id}&set={set_id}"
             photo_page = self.photo_page_request_wrapper(photo_url).text
 
             photo = self.parse_photo_page(photo_page)
@@ -317,7 +312,7 @@ class FacebookSetExtractor(FacebookExtractor):
             post_page = self.request(post_url).text
             set_id = self.parse_post_page(post_page)["set_id"]
 
-        set_url = self.set_url_fmt.format(set_id=set_id)
+        set_url = f"{self.root}/media/set/?set={set_id}"
         set_page = self.request(set_url).text
         set_data = self.parse_set_page(set_page)
         if self.groups[2]:
@@ -336,16 +331,15 @@ class FacebookPhotoExtractor(FacebookExtractor):
 
     def items(self):
         photo_id = self.groups[0]
-        photo_url = self.photo_url_fmt.format(photo_id=photo_id, set_id="")
+        photo_url = f"{self.root}/photo/?fbid={photo_id}&set="
         photo_page = self.photo_page_request_wrapper(photo_url).text
 
         i = 1
         photo = self.parse_photo_page(photo_page)
         photo["num"] = i
 
-        set_page = self.request(
-            self.set_url_fmt.format(set_id=photo["set_id"])
-        ).text
+        set_url = f"{self.root}/media/set/?set={photo['set_id']}"
+        set_page = self.request(set_url).text
 
         directory = self.parse_set_page(set_page)
 
@@ -356,9 +350,7 @@ class FacebookPhotoExtractor(FacebookExtractor):
             for comment_photo_id in photo["followups_ids"]:
                 comment_photo = self.parse_photo_page(
                     self.photo_page_request_wrapper(
-                        self.photo_url_fmt.format(
-                            photo_id=comment_photo_id, set_id=""
-                        )
+                        f"{self.root}/photo/?fbid={comment_photo_id}&set="
                     ).text
                 )
                 i += 1
@@ -426,7 +418,7 @@ class FacebookProfileExtractor(FacebookExtractor):
         set_id = self.get_profile_photos_set_id(profile_photos_page)
 
         if set_id:
-            set_url = self.set_url_fmt.format(set_id=set_id)
+            set_url = f"{self.root}/media/set/?set={set_id}"
             set_page = self.request(set_url).text
             set_data = self.parse_set_page(set_page)
             return self.extract_set(set_data)
diff --git a/gallery_dl/extractor/fanbox.py b/gallery_dl/extractor/fanbox.py
index 566e470c..381d88ff 100644
--- a/gallery_dl/extractor/fanbox.py
+++ b/gallery_dl/extractor/fanbox.py
@@ -337,8 +337,8 @@ class FanboxExtractor(Extractor):
         elif provider == "twitter":
             url = "https://twitter.com/_/status/"+content_id
         elif provider == "google_forms":
-            templ = "https://docs.google.com/forms/d/e/{}/viewform?usp=sf_link"
-            url = templ.format(content_id)
+            url = (f"https://docs.google.com/forms/d/e/"
+                   f"{content_id}/viewform?usp=sf_link")
         else:
             self.log.warning(f"service not recognized: {provider}")
 
diff --git a/gallery_dl/extractor/furaffinity.py b/gallery_dl/extractor/furaffinity.py
index 8bcadb11..2c8d576e 100644
--- a/gallery_dl/extractor/furaffinity.py
+++ b/gallery_dl/extractor/furaffinity.py
@@ -324,11 +324,12 @@ class FuraffinityUserExtractor(Dispatch, FuraffinityExtractor):
     example = "https://www.furaffinity.net/user/USER/"
 
     def items(self):
-        base = f"{self.root}/{{}}/{self.user}/"
+        base = self.root
+        user = f"{self.user}/"
         return self._dispatch_extractors((
-            (FuraffinityGalleryExtractor , base.format("gallery")),
-            (FuraffinityScrapsExtractor  , base.format("scraps")),
-            (FuraffinityFavoriteExtractor, base.format("favorites")),
+            (FuraffinityGalleryExtractor , f"{base}/gallery/{user}"),
+            (FuraffinityScrapsExtractor  , f"{base}/scraps/{user}"),
+            (FuraffinityFavoriteExtractor, f"{base}/favorites/{user}"),
         ), ("gallery",))
 
 
diff --git a/gallery_dl/extractor/issuu.py b/gallery_dl/extractor/issuu.py
index 048ebba3..06c5caa5 100644
--- a/gallery_dl/extractor/issuu.py
+++ b/gallery_dl/extractor/issuu.py
@@ -39,18 +39,15 @@ class IssuuPublicationExtractor(IssuuBase, GalleryExtractor):
         doc["date"] = text.parse_datetime(
             doc["originalPublishDateInISOString"], "%Y-%m-%dT%H:%M:%S.%fZ")
 
-        self._cnt = text.parse_int(doc["pageCount"])
-        self._tpl = "https://{}/{}-{}/jpg/page_{{}}.jpg".format(
-            "image.isu.pub",  # data["config"]["hosts"]["image"],
-            doc["revisionId"],
-            doc["publicationId"],
-        )
+        self.count = text.parse_int(doc["pageCount"])
+        self.base = (f"https://image.isu.pub/{doc['revisionId']}-"
+                     f"{doc['publicationId']}/jpg/page_")
 
         return {"document": doc}
 
     def images(self, page):
-        fmt = self._tpl.format
-        return [(fmt(i), None) for i in range(1, self._cnt + 1)]
+        return [(f"{self.base}{i}.jpg", None)
+                for i in range(1, self.count + 1)]
 
 
 class IssuuUserExtractor(IssuuBase, Extractor):
diff --git a/gallery_dl/extractor/mangadex.py b/gallery_dl/extractor/mangadex.py
index bea5c84f..df3cf756 100644
--- a/gallery_dl/extractor/mangadex.py
+++ b/gallery_dl/extractor/mangadex.py
@@ -354,7 +354,7 @@ class MangadexAPI():
                 self.extractor.wait(until=until)
                 continue
 
-            msg = ", ".join('{title}: "{detail}"'.format_map(error)
+            msg = ", ".join(f'{error["title"]}: "{error["detail"]}"'
                             for error in response.json()["errors"])
             raise exception.AbortExtraction(
                 f"{response.status_code} {response.reason} ({msg})")
diff --git a/gallery_dl/extractor/mangahere.py b/gallery_dl/extractor/mangahere.py
index bc7b683a..151e8093 100644
--- a/gallery_dl/extractor/mangahere.py
+++ b/gallery_dl/extractor/mangahere.py
@@ -17,7 +17,6 @@ class MangahereBase():
     category = "mangahere"
     root = "https://www.mangahere.cc"
     root_mobile = "https://m.mangahere.cc"
-    url_fmt = root_mobile + "/manga/{}/{}.html"
 
 
 class MangahereChapterExtractor(MangahereBase, ChapterExtractor):
@@ -28,8 +27,8 @@ class MangahereChapterExtractor(MangahereBase, ChapterExtractor):
 
     def __init__(self, match):
         self.part, self.volume, self.chapter = match.groups()
-        url = self.url_fmt.format(self.part, 1)
-        ChapterExtractor.__init__(self, match, url)
+        self.base = f"{self.root_mobile}/manga/{self.part}/"
+        ChapterExtractor.__init__(self, match, f"{self.base}1.html")
 
     def _init(self):
         self.session.headers["Referer"] = self.root_mobile + "/"
@@ -64,7 +63,7 @@ class MangahereChapterExtractor(MangahereBase, ChapterExtractor):
             url, pos = text.extract(page, ' src="', '"', pos)
             yield text.ensure_http_scheme(text.unescape(url)), None
             pnum += 2
-            page = self.request(self.url_fmt.format(self.part, pnum)).text
+            page = self.request(f"{self.base}{pnum}.html").text
 
     def _get_title(self):
         url = f"{self.root}/manga/{self.part}/"
diff --git a/gallery_dl/extractor/oauth.py b/gallery_dl/extractor/oauth.py
index 9bafcfc3..ad4367cf 100644
--- a/gallery_dl/extractor/oauth.py
+++ b/gallery_dl/extractor/oauth.py
@@ -214,19 +214,17 @@ class OAuthBase(Extractor):
             ("These values have", "these values", "are", "them")
         )
 
-        msg = "\nYour {} {}\n\n{}\n\n".format(
-            " and ".join("'" + n + "'" for n in names),
-            _is,
-            "\n".join(values),
-        )
+        key = " and ".join(f"'{n}'" for n in names)
+        val = "\n".join(values)
+        msg = f"\nYour {key} {_is}\n\n{val}\n\n"
 
         opt = self.oauth_config(names[0])
         if self.cache and (opt is None or opt == "cache"):
             msg += _vh + " been cached and will automatically be used.\n"
         else:
-            msg += "Put " + _va + " into your configuration file as \n"
+            msg += f"Put {_va} into your configuration file as \n"
             msg += " and\n".join(
-                "'extractor." + self.subcategory + "." + n + "'"
+                f"'extractor.{self.subcategory}.{n}'"
                 for n in names
             )
             if self.cache:
diff --git a/gallery_dl/extractor/pixnet.py b/gallery_dl/extractor/pixnet.py
index b85b3e18..75c06bb8 100644
--- a/gallery_dl/extractor/pixnet.py
+++ b/gallery_dl/extractor/pixnet.py
@@ -19,11 +19,10 @@ class PixnetExtractor(Extractor):
     category = "pixnet"
     filename_fmt = "{num:>03}_{id}.{extension}"
     archive_fmt = "{id}"
-    url_fmt = ""
 
     def __init__(self, match):
         Extractor.__init__(self, match)
-        self.blog, self.item_id = match.groups()
+        self.blog, self.item_id = self.groups
         self.root = f"https://{self.blog}.pixnet.net"
 
     def items(self):
@@ -91,14 +90,13 @@ class PixnetImageExtractor(PixnetExtractor):
 class PixnetSetExtractor(PixnetExtractor):
     """Extractor for images from a pixnet set"""
     subcategory = "set"
-    url_fmt = "{}/album/set/{}"
     directory_fmt = ("{category}", "{blog}",
                      "{folder_id} {folder_title}", "{set_id} {set_title}")
     pattern = BASE_PATTERN + r"/album/set/(\d+)"
     example = "https://USER.pixnet.net/album/set/12345"
 
     def items(self):
-        url = self.url_fmt.format(self.root, self.item_id)
+        url = f"{self.root}/album/set/{self.item_id}"
         page = self.request(url, encoding="utf-8").text
         data = self.metadata(page)
 
diff --git a/gallery_dl/extractor/wikifeet.py b/gallery_dl/extractor/wikifeet.py
index 4f822e5c..31dc9cd1 100644
--- a/gallery_dl/extractor/wikifeet.py
+++ b/gallery_dl/extractor/wikifeet.py
@@ -50,9 +50,11 @@ class WikifeetGalleryExtractor(GalleryExtractor):
             "S": "Soles",
             "B": "Barefoot",
         }
-        ufmt = "https://pics.wikifeet.com/" + self.celeb + "-Feet-{}.jpg"
+
+        gallery = text.extr(page, '"gallery":[', '],')
+        base = f"https://pics.wikifeet.com/{self.celeb}-Feet-"
         return [
-            (ufmt.format(data["pid"]), {
+            (f"{base}{data['pid']}.jpg", {
                 "pid"   : data["pid"],
                 "width" : data["pw"],
                 "height": data["ph"],
@@ -61,6 +63,5 @@ class WikifeetGalleryExtractor(GalleryExtractor):
                     for tag in data["tags"] if tag in tagmap
                 ],
             })
-            for data in
-            util.json_loads("[" + text.extr(page, '"gallery":[', '],') + "]")
+            for data in util.json_loads(f"[{gallery}]")
         ]
diff --git a/gallery_dl/extractor/xfolio.py b/gallery_dl/extractor/xfolio.py
index b68b779c..12f437af 100644
--- a/gallery_dl/extractor/xfolio.py
+++ b/gallery_dl/extractor/xfolio.py
@@ -47,9 +47,6 @@ class XfolioWorkExtractor(XfolioExtractor):
     subcategory = "work"
     pattern = BASE_PATTERN + r"/portfolio/([^/?#]+)/works/(\d+)"
     example = "https://xfolio.jp/portfolio/USER/works/12345"
-    ref_fmt = ("{}/fullscale_image?image_id={}&work_id={}")
-    url_fmt = ("{}/user_asset.php?id={}&work_id={}"
-               "&work_image_id={}&type=work_image")
 
     def items(self):
         creator, work_id = self.groups
@@ -98,10 +95,11 @@ class XfolioWorkExtractor(XfolioExtractor):
             files.append({
                 "image_id" : image_id,
                 "extension": "jpg",
-                "url": self.url_fmt.format(
-                    self.root, image_id, work_id, image_id),
-                "_http_headers": {"Referer": self.ref_fmt.format(
-                    self.root, image_id, work_id)},
+                "url": (f"{self.root}/user_asset.php?id={image_id}&work_id="
+                        f"{work_id}&work_image_id={image_id}&type=work_image"),
+                "_http_headers": {"Referer": (
+                    f"{self.root}/fullscale_image"
+                    f"?image_id={image_id}&work_id={work_id}")},
             })
 
         return files