diff --git a/requirements.txt b/requirements.txt
index ff8797eb6..02a4c51b3 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -11,3 +11,4 @@ packaging >= 16.8
 roman >= 2.0.0
 beautifulsoup4 >= 4.6.0
 pyyaml >= 5.1
+python-jose==3.0.1
\ No newline at end of file
diff --git a/service/esi.py b/service/esi.py
index 4251c89ce..9a3cf45dd 100644
--- a/service/esi.py
+++ b/service/esi.py
@@ -14,7 +14,7 @@ from eos.saveddata.ssocharacter import SsoCharacter
 from service.esiAccess import APIException
 import gui.globalEvents as GE
 from gui.ssoLogin import SsoLogin, SsoLoginServer
-from service.server import StoppableHTTPServer, AuthHandler
+from service.server import StoppableHTTPServer, AuthHandler, SSOError
 from service.settings import EsiSettings
 from service.esiAccess import EsiAccess
 import gui.mainFrame
@@ -134,14 +134,7 @@ class Esi(EsiAccess):
         return 'http://localhost:{}'.format(port)
 
     def handleLogin(self, message):
-
-        # we already have authenticated stuff for the auto mode
-        if self.settings.get('ssoMode') == EsiSsoMode.AUTO:
-            ssoInfo = message['SSOInfo'][0]
-            auth_response = json.loads(base64.b64decode(ssoInfo))
-        else:
-            # otherwise, we need to fetch the information
-            auth_response = self.auth(message['code'][0])
+        auth_response = self.auth(message['code'][0])
 
         res = self._session.get(
             self.oauth_verify,
@@ -169,11 +162,17 @@ class Esi(EsiAccess):
 
     def handleServerLogin(self, message):
         if not message:
-            raise Exception("Could not parse out querystring parameters.")
+            raise SSOError("Could not parse out querystring parameters.")
 
-        if message['state'][0] != self.state:
+        try:
+            state_enc = message['state'][0]
+            state = json.loads(base64.b64decode(state_enc))['state']
+        except Exception:
+            raise SSOError("There was a problem decoding state parameter.")
+
+        if state != self.state:
             pyfalog.warn("OAUTH state mismatch")
-            raise Exception("OAUTH State Mismatch.")
+            raise SSOError("OAUTH State Mismatch.")
 
         pyfalog.debug("Handling SSO login with: {0}", message)
 
diff --git a/service/esiAccess.py b/service/esiAccess.py
index b24ca898c..a5de73430 100644
--- a/service/esiAccess.py
+++ b/service/esiAccess.py
@@ -18,9 +18,12 @@ import base64
 import secrets
 import hashlib
 import json
+from jose import jwt
+from jose.exceptions import ExpiredSignatureError, JWTError, JWTClaimsError
 
 import datetime
 from service.const import EsiSsoMode, EsiEndpoints
+from service.server import SSOError
 from service.settings import EsiSettings, NetworkSettings
 
 from requests import Session
@@ -131,45 +134,37 @@ class EsiAccess:
     def getLoginURI(self, redirect=None):
         self.state = str(uuid.uuid4())
 
-        if self.settings.get("ssoMode") == EsiSsoMode.AUTO:
+        # Generate the PKCE code challenge
+        self.code_verifier = base64.urlsafe_b64encode(secrets.token_bytes(32))
+        m = hashlib.sha256()
+        m.update(self.code_verifier)
+        d = m.digest()
+        code_challenge = base64.urlsafe_b64encode(d).decode().replace("=", "")
 
-            # Generate the PKCE code challenge
-            code_verifier = base64.urlsafe_b64encode(secrets.token_bytes(32))
-            m = hashlib.sha256()
-            m.update(code_verifier)
-            d = m.digest()
-            code_challenge = base64.urlsafe_b64encode(d).decode().replace("=", "")
-            state_arg = {
-                'mode': self.settings.get('loginMode'),
-                'redirect': redirect,
-                'state': self.state
-            }
-            args = {
-                # 'pyfa_version': config.version,
-                # 'login_method': self.settings.get('loginMode'), # todo: encode this into the state
-                # 'client_hash': config.getClientSecret(),
-                'response_type': 'code',
-                'redirect_uri': 'http://127.0.0.1:5500/callback.html',
-                'client_id': '095d8cd841ac40b581330919b49fe746', # pyfa PKCE app # TODO: move this to some central config location, not hardcoded
-                'scope': ' '.join(scopes),
-                'code_challenge': code_challenge,
-                'code_challenge_method':  'S256',
-                'state': base64.b64encode(bytes(json.dumps(state_arg), 'utf-8'))
-            }
+        state_arg = {
+            'mode': self.settings.get('loginMode'),
+            'redirect': redirect,
+            'state': self.state
+        }
+
+        args = {
+            # 'pyfa_version': config.version,
+            # 'login_method': self.settings.get('loginMode'), # todo: encode this into the state
+            # 'client_hash': config.getClientSecret(),
+            'response_type': 'code',
+            'redirect_uri': 'http://127.0.0.1:5500/callback.html',
+            'client_id': self.settings.get('clientID') or '095d8cd841ac40b581330919b49fe746', # pyfa PKCE app # TODO: move this to some central config location, not hardcoded
+            'scope': ' '.join(scopes),
+            'code_challenge': code_challenge,
+            'code_challenge_method':  'S256',
+            'state': base64.b64encode(bytes(json.dumps(state_arg), 'utf-8'))
+        }
+
+        return '%s?%s' % (
+            self.oauth_authorize,
+            urlencode(args)
+        )
 
-            return '%s?%s' % (
-                self.oauth_authorize,
-                urlencode(args)
-            )
-        else:
-            return '%s?response_type=%s&redirect_uri=%s&client_id=%s%s%s' % (
-                self.oauth_authorize,
-                'code',
-                quote('http://localhost:6461', safe=''),
-                self.settings.get('clientID'),
-                '&scope=%s' % '+'.join(scopes) if scopes else '',
-                '&state=%s' % self.state
-            )
 
     def get_oauth_header(self, token):
         """ Return the Bearer Authorization header required in oauth calls
@@ -229,21 +224,83 @@ class EsiAccess:
             {
                 'grant_type': 'authorization_code',
                 'code': code,
+                'client_id': self.settings.get('clientID') or '095d8cd841ac40b581330919b49fe746',
+                "code_verifier": self.code_verifier
             }
         )
 
     def auth(self, code):
-        request_data = self.get_access_token_request_params(code)
-        res = self._session.post(**request_data)
+        # todo: handle invalid auth code, or one that has been used already
+        values = {
+            'grant_type': 'authorization_code',
+            'code': code,
+            'client_id': self.settings.get('clientID') or '095d8cd841ac40b581330919b49fe746',
+            "code_verifier": self.code_verifier
+        }
+
+        headers = {
+            "Content-Type": "application/x-www-form-urlencoded",
+            "Host": "login.eveonline.com",
+        }
+
+        res = self._session.post(
+            "https://login.eveonline.com/v2/oauth/token",
+            data=values,
+            headers=headers,
+        )
+
         if res.status_code != 200:
-            raise Exception(
-                request_data['url'],
+            raise SSOError(
+                "https://login.eveonline.com/v2/oauth/token",
                 res.status_code,
                 res.json()
             )
         json_res = res.json()
+
+        self.validate_eve_jwt(json_res['access_token'])
         return json_res
 
+    def validate_eve_jwt(self, jwt_token):
+        """Validate a JWT token retrieved from the EVE SSO.
+        Args:
+            jwt_token: A JWT token originating from the EVE SSO
+        Returns
+            dict: The contents of the validated JWT token if there are no
+                  validation errors
+        """
+
+        jwk_set_url = "https://login.eveonline.com/oauth/jwks"
+
+        res = self._session.get(jwk_set_url)
+        res.raise_for_status()
+
+        data = res.json()
+
+        try:
+            jwk_sets = data["keys"]
+        except KeyError as e:
+            raise SSOError("Something went wrong when retrieving the JWK set. The returned "
+                  "payload did not have the expected key {}. \nPayload returned "
+                  "from the SSO looks like: {}".format(e, data))
+
+        jwk_set = next((item for item in jwk_sets if item["alg"] == "RS256"))
+
+        try:
+            return jwt.decode(
+                jwt_token,
+                jwk_set,
+                algorithms=jwk_set["alg"],
+                issuer=["login.eveonline.com", "https://login.eveonline.com"]
+            )
+        except ExpiredSignatureError as e:
+            raise SSOError("The JWT token has expired: {}").format(str(e))
+        except JWTError as e:
+            raise SSOError("The JWT signature was invalid: {}").format(str(e))
+        except JWTClaimsError as e:
+            raise SSOError("The issuer claim was not from login.eveonline.com or "
+                "https://login.eveonline.com: {}".format(str(e)))
+
+
     def refresh(self, ssoChar):
         request_data = self.get_refresh_token_params(config.cipher.decrypt(ssoChar.refreshToken).decode())
         res = self._session.post(**request_data)
diff --git a/service/server.py b/service/server.py
index 55c65c903..0e5ebe2fe 100644
--- a/service/server.py
+++ b/service/server.py
@@ -5,67 +5,11 @@ import threading
 from logbook import Logger
 import socketserver
 import json
+
 pyfalog = Logger(__name__)
 
-# noinspection PyPep8
-HTML = '''
-<!DOCTYPE html>
-<html>
-
-<head>
-    <meta http-equiv="Content-type" content="text/html;charset=UTF-8">
-    <title>pyfa Local Server</title>
-    <style type="text/css">
-        body {{ text-align: center; padding: 150px; }}
-        h1 {{ font-size: 40px; }}
-        h2 {{ font-size: 32px; }}
-        body {{ font: 20px Helvetica, sans-serif; color: #333; }}
-        #article {{ display: block; text-align: left; width: 650px; margin: 0 auto; }}
-        a {{ color: #dc8100; text-decoration: none; }}
-        a:hover {{ color: #333; text-decoration: none; }}
-    </style>
-</head>
-
-<body>
-
-<!-- Layout from Short Circuit's CREST login. Shout out! https://github.com/farshield/shortcircuit -->
-<div id="article">
-    <h1>pyfa</h1>
-    {0}
-</div>
-
-<script type="text/javascript">
-function extractFromHash(name, hash) {{
-    var match = hash.match(new RegExp(name + "=([^&]+)"));
-    return !!match && match[1];
-}}
-
-var hash = window.location.hash;
-var token = extractFromHash("access_token", hash);
-var step2 = extractFromHash("step2", hash);
-
-function doRedirect() {{
-    if (token){{
-        // implicit authentication
-        var redirect = window.location.origin.concat('/?', window.location.hash.substr(1), '&step=2');
-        window.location = redirect;
-    }}
-    else {{
-        // user-defined
-        var redirect = window.location.href + '&step=2';
-        window.location = redirect;
-    }}
-}}
-
-// do redirect if we are not already on step 2
-if (window.location.href.indexOf('step=2') == -1) {{
-    setTimeout(doRedirect(), 1000);
-}}
-</script>
-</body>
-</html>
-'''
-
+class SSOError(Exception):
+    pass
 
 # https://github.com/fuzzysteve/CREST-Market-Downloader/
 class AuthHandler(http.server.BaseHTTPRequestHandler):
@@ -86,16 +30,26 @@ class AuthHandler(http.server.BaseHTTPRequestHandler):
             pyfalog.info("Successfully logged into EVE.")
             is_success = True
             self.send_response(200)
+            self.send_header('Access-Control-Allow-Origin', '*')
+            self.end_headers()
         except (KeyboardInterrupt, SystemExit):
             raise
+        except SSOError as ex:
+            pyfalog.error("Error logging into EVE")
+            pyfalog.error(ex)
+            self.send_response(500)
+            self.send_header('Access-Control-Allow-Origin', '*')
+            self.end_headers()
+            self.wfile.write(str.encode(str(ex)))
         except Exception as ex:
             pyfalog.error("Error logging into EVE")
             pyfalog.error(ex)
             self.send_response(500)
-            # send error
-        finally:
             self.send_header('Access-Control-Allow-Origin', '*')
             self.end_headers()
+            # send error
+
+
 
         if is_success:
             self.server.stop()