diff --git a/alertaclient/api.py b/alertaclient/api.py
index 965bb55..4ab8e47 100644
--- a/alertaclient/api.py
+++ b/alertaclient/api.py
@@ -150,22 +150,22 @@ def alert_note(self, id, text):
         data = {
             'text': text
         }
-        r = self.http.put('/alert/{}/note'.format(id), data)
+        r = self.http.put(f'/alert/{id}/note', data)
         return Note.parse(r['note'])
 
     def get_alert_notes(self, id, page=1, page_size=None):
-        r = self.http.get('/alert/{}/notes'.format(id), page=page, page_size=page_size)
+        r = self.http.get(f'/alert/{id}/notes', page=page, page_size=page_size)
         return [Note.parse(n) for n in r['notes']]
 
     def update_alert_note(self, id, note_id, text):
         data = {
             'text': text,
         }
-        r = self.http.put('/alert/{}/note/{}'.format(id, note_id), data)
+        r = self.http.put(f'/alert/{id}/note/{note_id}', data)
         return Note.parse(r['note'])
 
     def delete_alert_note(self, id, note_id):
-        return self.http.delete('/alert/{}/note/{}'.format(id, note_id))
+        return self.http.delete(f'/alert/{id}/note/{note_id}')
 
     # Blackouts
     def create_blackout(self, environment, service=None, resource=None, event=None, group=None, tags=None,
@@ -208,7 +208,7 @@ def update_blackout(self, id, **kwargs):
             'text': kwargs.get('text'),
         }
 
-        r = self.http.put('/blackout/{}'.format(id), data)
+        r = self.http.put(f'/blackout/{id}', data)
         return Blackout.parse(r['blackout'])
 
     def delete_blackout(self, id):
@@ -235,7 +235,7 @@ def update_customer(self, id, **kwargs):
             'match': kwargs.get('match'),
             'customer': kwargs.get('customer')
         }
-        r = self.http.put('/customer/{}'.format(id), data)
+        r = self.http.put(f'/customer/{id}', data)
         return Customer.parse(r['customer'])
 
     def delete_customer(self, id):
@@ -292,7 +292,7 @@ def update_key(self, id, **kwargs):
             'expireTime': kwargs.get('expireTime'),
             'customer': kwargs.get('customer')
         }
-        r = self.http.put('/key/{}'.format(id), data)
+        r = self.http.put(f'/key/{id}', data)
         return ApiKey.parse(r['key'])
 
     def delete_key(self, id):
@@ -319,7 +319,7 @@ def update_perm(self, id, **kwargs):
             'match': kwargs.get('match'),  # role
             'scopes': kwargs.get('scopes')
         }
-        r = self.http.put('/perm/{}'.format(id), data)
+        r = self.http.put(f'/perm/{id}', data)
         return Permission.parse(r['permission'])
 
     def delete_perm(self, id):
@@ -359,7 +359,7 @@ def get_user(self, id):
         return User.parse(self.http.get('/user/%s' % id)['user'])
 
     def get_user_groups(self, id):
-        r = self.http.get('/user/{}/groups'.format(id))
+        r = self.http.get(f'/user/{id}/groups')
         return [Group.parse(g) for g in r['groups']]
 
     def get_me(self):
@@ -383,7 +383,7 @@ def update_user(self, id, **kwargs):
             'text': kwargs.get('text'),
             'email_verified': kwargs.get('email_verified')
         }
-        r = self.http.put('/user/{}'.format(id), data)
+        r = self.http.put(f'/user/{id}', data)
         return User.parse(r['user'])
 
     def update_me(self, **kwargs):
@@ -452,7 +452,7 @@ def get_group(self):
         return Group.parse(self.http.get('/group/%s' % id)['group'])
 
     def get_group_users(self, id):
-        r = self.http.get('/group/{}/users'.format(id))
+        r = self.http.get(f'/group/{id}/users')
         return [User.parse(u) for u in r['users']]
 
     def get_users_groups(self, query=None):
@@ -464,14 +464,14 @@ def update_group(self, id, **kwargs):
             'name': kwargs.get('name'),
             'text': kwargs.get('text')
         }
-        r = self.http.put('/group/{}'.format(id), data)
+        r = self.http.put(f'/group/{id}', data)
         return Group.parse(r['group'])
 
     def add_user_to_group(self, group_id, user_id):
-        return self.http.put('/group/{}/user/{}'.format(group_id, user_id))
+        return self.http.put(f'/group/{group_id}/user/{user_id}')
 
     def remove_user_from_group(self, group_id, user_id):
-        return self.http.delete('/group/{}/user/{}'.format(group_id, user_id))
+        return self.http.delete(f'/group/{group_id}/user/{user_id}')
 
     def delete_group(self, id):
         return self.http.delete('/group/%s' % id)
@@ -500,7 +500,7 @@ def __init__(self, api_key=None, auth_token=None):
         self.auth_token = auth_token
 
     def __call__(self, r):
-        r.headers['Authorization'] = 'Key {}'.format(self.api_key)
+        r.headers['Authorization'] = f'Key {self.api_key}'
         return r
 
 
@@ -510,7 +510,7 @@ def __init__(self, auth_token=None):
         self.auth_token = auth_token
 
     def __call__(self, r):
-        r.headers['Authorization'] = 'Bearer {}'.format(self.auth_token)
+        r.headers['Authorization'] = f'Bearer {self.auth_token}'
         return r
 
 
@@ -608,7 +608,7 @@ def delete(self, path):
 
     def _handle_error(self, response):
         if self.debug:
-            print('\nbody: {}'.format(response.text))
+            print(f'\nbody: {response.text}')
         resp = response.json()
         status = resp.get('status', None)
         if status == 'ok':
diff --git a/alertaclient/auth/utils.py b/alertaclient/auth/utils.py
index 2fa85e1..d966cf5 100644
--- a/alertaclient/auth/utils.py
+++ b/alertaclient/auth/utils.py
@@ -29,7 +29,7 @@ def save_token(endpoint, username, token):
     try:
         info = netrc(NETRC_FILE)
     except Exception as e:
-        raise ConfigurationError('{}'.format(e))
+        raise ConfigurationError(f'{e}')
     info.hosts[machine(endpoint)] = (username, None, token)
     with open(NETRC_FILE, 'w') as f:
         f.write(dump_netrc(info))
@@ -39,13 +39,13 @@ def clear_token(endpoint):
     try:
         info = netrc(NETRC_FILE)
     except Exception as e:
-        raise ConfigurationError('{}'.format(e))
+        raise ConfigurationError(f'{e}')
     try:
         del info.hosts[machine(endpoint)]
         with open(NETRC_FILE, 'w') as f:
             f.write(dump_netrc(info))
     except KeyError as e:
-        raise ConfigurationError('No credentials stored for {}'.format(e))
+        raise ConfigurationError(f'No credentials stored for {e}')
 
 
 # See https://bugs.python.org/issue30806
diff --git a/alertaclient/commands/cmd_ack.py b/alertaclient/commands/cmd_ack.py
index aaf58ee..1797020 100644
--- a/alertaclient/commands/cmd_ack.py
+++ b/alertaclient/commands/cmd_ack.py
@@ -22,4 +22,4 @@ def cli(obj, ids, query, filters, text):
         total, _, _ = client.get_count(query)
         ids = [a.id for a in client.get_alerts(query)]
 
-    action_progressbar(client, action='ack', ids=ids, label='Acking {} alerts'.format(total), text=text)
+    action_progressbar(client, action='ack', ids=ids, label=f'Acking {total} alerts', text=text)
diff --git a/alertaclient/commands/cmd_action.py b/alertaclient/commands/cmd_action.py
index 55095e9..be4b29b 100644
--- a/alertaclient/commands/cmd_action.py
+++ b/alertaclient/commands/cmd_action.py
@@ -23,5 +23,5 @@ def cli(obj, action, ids, query, filters, text):
         total, _, _ = client.get_count(query)
         ids = [a.id for a in client.get_alerts(query)]
 
-    label = 'Action ({}) {} alerts'.format(action, total)
+    label = f'Action ({action}) {total} alerts'
     action_progressbar(client, action=action, ids=ids, label=label, text=text)
diff --git a/alertaclient/commands/cmd_blackout.py b/alertaclient/commands/cmd_blackout.py
index 2810efc..697a4df 100644
--- a/alertaclient/commands/cmd_blackout.py
+++ b/alertaclient/commands/cmd_blackout.py
@@ -40,6 +40,6 @@ def cli(obj, environment, service, resource, event, group, tags, origin, custome
                 text=text
             )
         except Exception as e:
-            click.echo('ERROR: {}'.format(e), err=True)
+            click.echo(f'ERROR: {e}', err=True)
             sys.exit(1)
         click.echo(blackout.id)
diff --git a/alertaclient/commands/cmd_blackouts.py b/alertaclient/commands/cmd_blackouts.py
index 583dd33..edbb77e 100644
--- a/alertaclient/commands/cmd_blackouts.py
+++ b/alertaclient/commands/cmd_blackouts.py
@@ -27,6 +27,6 @@ def cli(obj, purge):
 
         expired = [b for b in blackouts if b.status == 'expired']
         if purge:
-            with click.progressbar(expired, label='Purging {} blackouts'.format(len(expired))) as bar:
+            with click.progressbar(expired, label=f'Purging {len(expired)} blackouts') as bar:
                 for b in bar:
                     client.delete_blackout(b.id)
diff --git a/alertaclient/commands/cmd_close.py b/alertaclient/commands/cmd_close.py
index e3576b7..8b7ac78 100644
--- a/alertaclient/commands/cmd_close.py
+++ b/alertaclient/commands/cmd_close.py
@@ -22,4 +22,4 @@ def cli(obj, ids, query, filters, text):
         total, _, _ = client.get_count(query)
         ids = [a.id for a in client.get_alerts(query)]
 
-    action_progressbar(client, action='close', ids=ids, label='Closing {} alerts'.format(total), text=text)
+    action_progressbar(client, action='close', ids=ids, label=f'Closing {total} alerts', text=text)
diff --git a/alertaclient/commands/cmd_config.py b/alertaclient/commands/cmd_config.py
index f458601..04b7c4e 100644
--- a/alertaclient/commands/cmd_config.py
+++ b/alertaclient/commands/cmd_config.py
@@ -8,4 +8,4 @@ def cli(obj):
     for k, v in obj.items():
         if isinstance(v, list):
             v = ', '.join(v)
-        click.echo('{:20}: {}'.format(k, v))
+        click.echo(f'{k:20}: {v}')
diff --git a/alertaclient/commands/cmd_customer.py b/alertaclient/commands/cmd_customer.py
index 33942f3..51f7540 100644
--- a/alertaclient/commands/cmd_customer.py
+++ b/alertaclient/commands/cmd_customer.py
@@ -21,6 +21,6 @@ def cli(obj, customer, match, delete):
         try:
             customer = client.create_customer(customer, match)
         except Exception as e:
-            click.echo('ERROR: {}'.format(e), err=True)
+            click.echo(f'ERROR: {e}', err=True)
             sys.exit(1)
         click.echo(customer.id)
diff --git a/alertaclient/commands/cmd_delete.py b/alertaclient/commands/cmd_delete.py
index f333203..c3ca575 100644
--- a/alertaclient/commands/cmd_delete.py
+++ b/alertaclient/commands/cmd_delete.py
@@ -23,6 +23,6 @@ def cli(obj, ids, query, filters):
         total, _, _ = client.get_count(query)
         ids = [a.id for a in client.get_alerts(query)]
 
-    with click.progressbar(ids, label='Deleting {} alerts'.format(total)) as bar:
+    with click.progressbar(ids, label=f'Deleting {total} alerts') as bar:
         for id in bar:
             client.delete_alert(id)
diff --git a/alertaclient/commands/cmd_group.py b/alertaclient/commands/cmd_group.py
index 81c9ba8..63ec9a4 100644
--- a/alertaclient/commands/cmd_group.py
+++ b/alertaclient/commands/cmd_group.py
@@ -56,6 +56,6 @@ def cli(obj, id, name, text, user, users, delete):
         try:
             group = client.create_group(name, text)
         except Exception as e:
-            click.echo('ERROR: {}'.format(e), err=True)
+            click.echo(f'ERROR: {e}', err=True)
             sys.exit(1)
         click.echo(group.id)
diff --git a/alertaclient/commands/cmd_heartbeat.py b/alertaclient/commands/cmd_heartbeat.py
index 3c6760a..901c948 100644
--- a/alertaclient/commands/cmd_heartbeat.py
+++ b/alertaclient/commands/cmd_heartbeat.py
@@ -52,6 +52,6 @@ def cli(obj, origin, environment, severity, service, group, tags, timeout, custo
         try:
             heartbeat = client.heartbeat(origin=origin, tags=tags, attributes=attributes, timeout=timeout, customer=customer)
         except Exception as e:
-            click.echo('ERROR: {}'.format(e), err=True)
+            click.echo(f'ERROR: {e}', err=True)
             sys.exit(1)
         click.echo(heartbeat.id)
diff --git a/alertaclient/commands/cmd_heartbeats.py b/alertaclient/commands/cmd_heartbeats.py
index 079f738..db9ffd1 100644
--- a/alertaclient/commands/cmd_heartbeats.py
+++ b/alertaclient/commands/cmd_heartbeats.py
@@ -48,12 +48,12 @@ def cli(obj, alert, severity, timeout, purge):
 
     not_ok = [hb for hb in heartbeats if hb.status != 'ok']
     if purge:
-        with click.progressbar(not_ok, label='Purging {} heartbeats'.format(len(not_ok))) as bar:
+        with click.progressbar(not_ok, label=f'Purging {len(not_ok)} heartbeats') as bar:
             for b in bar:
                 client.delete_heartbeat(b.id)
 
     if alert:
-        with click.progressbar(heartbeats, label='Alerting {} heartbeats'.format(len(heartbeats))) as bar:
+        with click.progressbar(heartbeats, label=f'Alerting {len(heartbeats)} heartbeats') as bar:
             for b in bar:
 
                 want_environment = b.attributes.pop('environment', 'Production')
@@ -70,8 +70,8 @@ def cli(obj, alert, severity, timeout, purge):
                         correlate=['HeartbeatFail', 'HeartbeatSlow', 'HeartbeatOK'],
                         service=want_service,
                         group=want_group,
-                        value='{}'.format(b.since),
-                        text='Heartbeat not received in {} seconds'.format(b.timeout),
+                        value=f'{b.since}',
+                        text=f'Heartbeat not received in {b.timeout} seconds',
                         tags=b.tags,
                         attributes=b.attributes,
                         origin=origin(),
@@ -88,8 +88,8 @@ def cli(obj, alert, severity, timeout, purge):
                         correlate=['HeartbeatFail', 'HeartbeatSlow', 'HeartbeatOK'],
                         service=want_service,
                         group=want_group,
-                        value='{}ms'.format(b.latency),
-                        text='Heartbeat took more than {}ms to be processed'.format(b.max_latency),
+                        value=f'{b.latency}ms',
+                        text=f'Heartbeat took more than {b.max_latency}ms to be processed',
                         tags=b.tags,
                         attributes=b.attributes,
                         origin=origin(),
diff --git a/alertaclient/commands/cmd_key.py b/alertaclient/commands/cmd_key.py
index a58cc0b..5889b1d 100644
--- a/alertaclient/commands/cmd_key.py
+++ b/alertaclient/commands/cmd_key.py
@@ -23,6 +23,6 @@ def cli(obj, api_key, username, scopes, duration, text, customer, delete):
             expires = datetime.utcnow() + timedelta(seconds=duration) if duration else None
             key = client.create_key(username, scopes, expires, text, customer, key=api_key)
         except Exception as e:
-            click.echo('ERROR: {}'.format(e), err=True)
+            click.echo(f'ERROR: {e}', err=True)
             sys.exit(1)
         click.echo(key.key)
diff --git a/alertaclient/commands/cmd_login.py b/alertaclient/commands/cmd_login.py
index 74191f6..ddbeac3 100644
--- a/alertaclient/commands/cmd_login.py
+++ b/alertaclient/commands/cmd_login.py
@@ -37,7 +37,7 @@ def cli(obj, username):
             password = click.prompt('Password', hide_input=True)
             token = client.login(username, password)['token']
         else:
-            click.echo('ERROR: unknown provider {provider}'.format(provider=provider), err=True)
+            click.echo(f'ERROR: unknown provider {provider}', err=True)
             sys.exit(1)
     except Exception as e:
         raise AuthError(e)
@@ -46,7 +46,7 @@ def cli(obj, username):
     preferred_username = jwt.parse(token)['preferred_username']
     if preferred_username:
         save_token(client.endpoint, preferred_username, token)
-        click.echo('Logged in as {}'.format(preferred_username))
+        click.echo(f'Logged in as {preferred_username}')
     else:
         click.echo('Failed to login.')
         sys.exit(1)
diff --git a/alertaclient/commands/cmd_me.py b/alertaclient/commands/cmd_me.py
index 09e7640..e073f73 100644
--- a/alertaclient/commands/cmd_me.py
+++ b/alertaclient/commands/cmd_me.py
@@ -20,6 +20,6 @@ def cli(obj, name, email, password, status, text):
     try:
         user = client.update_me(name=name, email=email, password=password, status=status, attributes=None, text=text)
     except Exception as e:
-        click.echo('ERROR: {}'.format(e), err=True)
+        click.echo(f'ERROR: {e}', err=True)
         sys.exit(1)
     click.echo(user.id)
diff --git a/alertaclient/commands/cmd_note.py b/alertaclient/commands/cmd_note.py
index c469b39..f341163 100644
--- a/alertaclient/commands/cmd_note.py
+++ b/alertaclient/commands/cmd_note.py
@@ -42,6 +42,6 @@ def cli(obj, alert_ids, query, filters, text, delete):
             total, _, _ = client.get_count(query)
             alert_ids = [a.id for a in client.get_alerts(query)]
 
-        with click.progressbar(alert_ids, label='Add note to {} alerts'.format(total)) as bar:
+        with click.progressbar(alert_ids, label=f'Add note to {total} alerts') as bar:
             for id in bar:
                 client.alert_note(id, text=text)
diff --git a/alertaclient/commands/cmd_notes.py b/alertaclient/commands/cmd_notes.py
index 7348454..fc57943 100644
--- a/alertaclient/commands/cmd_notes.py
+++ b/alertaclient/commands/cmd_notes.py
@@ -12,7 +12,7 @@ def cli(obj, alert_id):
     client = obj['client']
     if alert_id:
         if obj['output'] == 'json':
-            r = client.http.get('/alert/{}/notes'.format(alert_id))
+            r = client.http.get(f'/alert/{alert_id}/notes')
             click.echo(json.dumps(r['notes'], sort_keys=True, indent=4, ensure_ascii=False))
         else:
             timezone = obj['timezone']
diff --git a/alertaclient/commands/cmd_perm.py b/alertaclient/commands/cmd_perm.py
index 361acee..236ee59 100644
--- a/alertaclient/commands/cmd_perm.py
+++ b/alertaclient/commands/cmd_perm.py
@@ -21,6 +21,6 @@ def cli(obj, role, scopes, delete):
         try:
             perm = client.create_perm(role, scopes)
         except Exception as e:
-            click.echo('ERROR: {}'.format(e), err=True)
+            click.echo(f'ERROR: {e}', err=True)
             sys.exit(1)
         click.echo(perm.id)
diff --git a/alertaclient/commands/cmd_query.py b/alertaclient/commands/cmd_query.py
index fee7b67..f794cee 100644
--- a/alertaclient/commands/cmd_query.py
+++ b/alertaclient/commands/cmd_query.py
@@ -72,21 +72,21 @@ def cli(obj, ids, query, filters, display, from_date=None):
                     alert.group,
                     alert.event,
                     alert.value or 'n/a'), fg=color['fg'])
-                click.secho('   |{}'.format(alert.text), fg=color['fg'])
+                click.secho(f'   |{alert.text}', fg=color['fg'])
 
                 if display == 'full':
                     click.secho('    severity   | {} -> {}'.format(alert.previous_severity,
                                                                    alert.severity), fg=color['fg'])
-                    click.secho('    trend      | {}'.format(alert.trend_indication), fg=color['fg'])
-                    click.secho('    status     | {}'.format(alert.status), fg=color['fg'])
-                    click.secho('    resource   | {}'.format(alert.resource), fg=color['fg'])
-                    click.secho('    group      | {}'.format(alert.group), fg=color['fg'])
-                    click.secho('    event      | {}'.format(alert.event), fg=color['fg'])
-                    click.secho('    value      | {}'.format(alert.value), fg=color['fg'])
+                    click.secho(f'    trend      | {alert.trend_indication}', fg=color['fg'])
+                    click.secho(f'    status     | {alert.status}', fg=color['fg'])
+                    click.secho(f'    resource   | {alert.resource}', fg=color['fg'])
+                    click.secho(f'    group      | {alert.group}', fg=color['fg'])
+                    click.secho(f'    event      | {alert.event}', fg=color['fg'])
+                    click.secho(f'    value      | {alert.value}', fg=color['fg'])
                     click.secho('    tags       | {}'.format(' '.join(alert.tags)), fg=color['fg'])
 
                     for key, value in alert.attributes.items():
-                        click.secho('    {} | {}'.format(key.ljust(10), value), fg=color['fg'])
+                        click.secho(f'    {key.ljust(10)} | {value}', fg=color['fg'])
 
                     latency = alert.receive_time - alert.create_time
 
@@ -96,18 +96,18 @@ def cli(obj, ids, query, filters, display, from_date=None):
                         DateTime.localtime(alert.receive_time, timezone)), fg=color['fg'])
                     click.secho('        last received | {}'.format(
                         DateTime.localtime(alert.last_receive_time, timezone)), fg=color['fg'])
-                    click.secho('        latency       | {}ms'.format(latency.microseconds / 1000), fg=color['fg'])
-                    click.secho('        timeout       | {}s'.format(alert.timeout), fg=color['fg'])
+                    click.secho(f'        latency       | {latency.microseconds / 1000}ms', fg=color['fg'])
+                    click.secho(f'        timeout       | {alert.timeout}s', fg=color['fg'])
 
-                    click.secho('            alert id     | {}'.format(alert.id), fg=color['fg'])
-                    click.secho('            last recv id | {}'.format(alert.last_receive_id), fg=color['fg'])
-                    click.secho('            customer     | {}'.format(alert.customer), fg=color['fg'])
-                    click.secho('            environment  | {}'.format(alert.environment), fg=color['fg'])
+                    click.secho(f'            alert id     | {alert.id}', fg=color['fg'])
+                    click.secho(f'            last recv id | {alert.last_receive_id}', fg=color['fg'])
+                    click.secho(f'            customer     | {alert.customer}', fg=color['fg'])
+                    click.secho(f'            environment  | {alert.environment}', fg=color['fg'])
                     click.secho('            service      | {}'.format(','.join(alert.service)), fg=color['fg'])
-                    click.secho('            resource     | {}'.format(alert.resource), fg=color['fg'])
-                    click.secho('            type         | {}'.format(alert.event_type), fg=color['fg'])
-                    click.secho('            repeat       | {}'.format(alert.repeat), fg=color['fg'])
-                    click.secho('            origin       | {}'.format(alert.origin), fg=color['fg'])
+                    click.secho(f'            resource     | {alert.resource}', fg=color['fg'])
+                    click.secho(f'            type         | {alert.event_type}', fg=color['fg'])
+                    click.secho(f'            repeat       | {alert.repeat}', fg=color['fg'])
+                    click.secho(f'            origin       | {alert.origin}', fg=color['fg'])
                     click.secho('            correlate    | {}'.format(','.join(alert.correlate)), fg=color['fg'])
 
         return auto_refresh, last_time
diff --git a/alertaclient/commands/cmd_send.py b/alertaclient/commands/cmd_send.py
index 00ba2a3..bf01a2c 100644
--- a/alertaclient/commands/cmd_send.py
+++ b/alertaclient/commands/cmd_send.py
@@ -48,15 +48,15 @@ def send_alert(resource, event, **kwargs):
                 customer=kwargs.get('customer')
             )
         except Exception as e:
-            click.echo('ERROR: {}'.format(e), err=True)
+            click.echo(f'ERROR: {e}', err=True)
             sys.exit(1)
 
         if alert:
             if alert.repeat:
-                message = '{} duplicates'.format(alert.duplicate_count)
+                message = f'{alert.duplicate_count} duplicates'
             else:
-                message = '{} -> {}'.format(alert.previous_severity, alert.severity)
-        click.echo('{} ({})'.format(id, message))
+                message = f'{alert.previous_severity} -> {alert.severity}'
+        click.echo(f'{id} ({message})')
 
     # read raw data from file or stdin
     if raw_data and raw_data.startswith('@') or raw_data == '-':
@@ -71,7 +71,7 @@ def send_alert(resource, event, **kwargs):
                 try:
                     payload = json.loads(line)
                 except Exception as e:
-                    click.echo("ERROR: JSON parse failure - input must be in 'json_lines' format: {}".format(e), err=True)
+                    click.echo(f"ERROR: JSON parse failure - input must be in 'json_lines' format: {e}", err=True)
                     sys.exit(1)
                 send_alert(**payload)
             sys.exit(0)
diff --git a/alertaclient/commands/cmd_shelve.py b/alertaclient/commands/cmd_shelve.py
index 8c19faf..20a4e40 100644
--- a/alertaclient/commands/cmd_shelve.py
+++ b/alertaclient/commands/cmd_shelve.py
@@ -24,4 +24,4 @@ def cli(obj, ids, query, filters, timeout, text):
         ids = [a.id for a in client.get_alerts(query)]
 
     action_progressbar(client, action='shelve', ids=ids,
-                       label='Shelving {} alerts'.format(total), text=text, timeout=timeout)
+                       label=f'Shelving {total} alerts', text=text, timeout=timeout)
diff --git a/alertaclient/commands/cmd_signup.py b/alertaclient/commands/cmd_signup.py
index dfa736d..cf6be9c 100644
--- a/alertaclient/commands/cmd_signup.py
+++ b/alertaclient/commands/cmd_signup.py
@@ -22,7 +22,7 @@ def cli(obj, name, email, password, status, text):
     try:
         r = client.signup(name=name, email=email, password=password, status=status, attributes=None, text=text)
     except Exception as e:
-        click.echo('ERROR: {}'.format(e), err=True)
+        click.echo(f'ERROR: {e}', err=True)
         sys.exit(1)
     if 'token' in r:
         click.echo('Signed Up.')
diff --git a/alertaclient/commands/cmd_tag.py b/alertaclient/commands/cmd_tag.py
index ce749a3..f98c678 100644
--- a/alertaclient/commands/cmd_tag.py
+++ b/alertaclient/commands/cmd_tag.py
@@ -22,6 +22,6 @@ def cli(obj, ids, query, filters, tags):
         total, _, _ = client.get_count(query)
         ids = [a.id for a in client.get_alerts(query)]
 
-    with click.progressbar(ids, label='Tagging {} alerts'.format(total)) as bar:
+    with click.progressbar(ids, label=f'Tagging {total} alerts') as bar:
         for id in bar:
             client.tag_alert(id, tags)
diff --git a/alertaclient/commands/cmd_token.py b/alertaclient/commands/cmd_token.py
index a66cf55..044bbae 100644
--- a/alertaclient/commands/cmd_token.py
+++ b/alertaclient/commands/cmd_token.py
@@ -16,6 +16,6 @@ def cli(obj, decode):
         for k, v in jwt.parse(token).items():
             if isinstance(v, list):
                 v = ', '.join(v)
-            click.echo('{:20}: {}'.format(k, v))
+            click.echo(f'{k:20}: {v}')
     else:
         click.echo(token)
diff --git a/alertaclient/commands/cmd_unack.py b/alertaclient/commands/cmd_unack.py
index 23e26d7..64b25d5 100644
--- a/alertaclient/commands/cmd_unack.py
+++ b/alertaclient/commands/cmd_unack.py
@@ -22,4 +22,4 @@ def cli(obj, ids, query, filters, text):
         total, _, _ = client.get_count(query)
         ids = [a.id for a in client.get_alerts(query)]
 
-    action_progressbar(client, action='unack', ids=ids, label='Un-acking {} alerts'.format(total), text=text)
+    action_progressbar(client, action='unack', ids=ids, label=f'Un-acking {total} alerts', text=text)
diff --git a/alertaclient/commands/cmd_unshelve.py b/alertaclient/commands/cmd_unshelve.py
index 30348cb..278a8e7 100644
--- a/alertaclient/commands/cmd_unshelve.py
+++ b/alertaclient/commands/cmd_unshelve.py
@@ -22,4 +22,4 @@ def cli(obj, ids, query, filters, text):
         total, _, _ = client.get_count(query)
         ids = [a.id for a in client.get_alerts(query)]
 
-    action_progressbar(client, 'unshelve', ids, label='Un-shelving {} alerts'.format(total), text=text)
+    action_progressbar(client, 'unshelve', ids, label=f'Un-shelving {total} alerts', text=text)
diff --git a/alertaclient/commands/cmd_untag.py b/alertaclient/commands/cmd_untag.py
index 3214934..d2026cd 100644
--- a/alertaclient/commands/cmd_untag.py
+++ b/alertaclient/commands/cmd_untag.py
@@ -22,6 +22,6 @@ def cli(obj, ids, query, filters, tags):
         total, _, _ = client.get_count(query)
         ids = [a.id for a in client.get_alerts(query)]
 
-    with click.progressbar(ids, label='Untagging {} alerts'.format(total)) as bar:
+    with click.progressbar(ids, label=f'Untagging {total} alerts') as bar:
         for id in bar:
             client.untag_alert(id, tags)
diff --git a/alertaclient/commands/cmd_update.py b/alertaclient/commands/cmd_update.py
index 2873262..90c0155 100644
--- a/alertaclient/commands/cmd_update.py
+++ b/alertaclient/commands/cmd_update.py
@@ -22,6 +22,6 @@ def cli(obj, ids, query, filters, attributes):
         total, _, _ = client.get_count(query)
         ids = [a.id for a in client.get_alerts(query)]
 
-    with click.progressbar(ids, label='Updating {} alerts'.format(total)) as bar:
+    with click.progressbar(ids, label=f'Updating {total} alerts') as bar:
         for id in bar:
             client.update_attributes(id, dict(a.split('=') for a in attributes))
diff --git a/alertaclient/commands/cmd_user.py b/alertaclient/commands/cmd_user.py
index 532a757..491853e 100644
--- a/alertaclient/commands/cmd_user.py
+++ b/alertaclient/commands/cmd_user.py
@@ -56,7 +56,7 @@ def cli(obj, id, name, email, password, status, roles, text, email_verified, gro
                     roles=roles, attributes=None, text=text, email_verified=email_verified
                 )
             except Exception as e:
-                click.echo('ERROR: {}'.format(e), err=True)
+                click.echo(f'ERROR: {e}', err=True)
                 sys.exit(1)
             click.echo(user.id)
     else:
@@ -70,6 +70,6 @@ def cli(obj, id, name, email, password, status, roles, text, email_verified, gro
                 roles=roles, attributes=None, text=text, email_verified=email_verified
             )
         except Exception as e:
-            click.echo('ERROR: {}'.format(e), err=True)
+            click.echo(f'ERROR: {e}', err=True)
             sys.exit(1)
         click.echo(user.id)
diff --git a/alertaclient/commands/cmd_version.py b/alertaclient/commands/cmd_version.py
index b576353..60f639e 100644
--- a/alertaclient/commands/cmd_version.py
+++ b/alertaclient/commands/cmd_version.py
@@ -11,7 +11,7 @@ def cli(ctx, obj):
     """Show Alerta server and client versions."""
     client = obj['client']
     click.echo('alerta {}'.format(client.mgmt_status()['version']))
-    click.echo('alerta client {}'.format(client_version))
-    click.echo('requests {}'.format(requests_version))
-    click.echo('click {}'.format(click.__version__))
+    click.echo(f'alerta client {client_version}')
+    click.echo(f'requests {requests_version}')
+    click.echo(f'click {click.__version__}')
     ctx.exit()
diff --git a/alertaclient/commands/cmd_whoami.py b/alertaclient/commands/cmd_whoami.py
index 7feef78..f3861ac 100644
--- a/alertaclient/commands/cmd_whoami.py
+++ b/alertaclient/commands/cmd_whoami.py
@@ -12,6 +12,6 @@ def cli(obj, show_userinfo):
         for k, v in userinfo.items():
             if isinstance(v, list):
                 v = ', '.join(v)
-            click.echo('{:20}: {}'.format(k, v))
+            click.echo(f'{k:20}: {v}')
     else:
         click.echo(userinfo['preferred_username'])
diff --git a/alertaclient/config.py b/alertaclient/config.py
index 9c46f38..43953d1 100644
--- a/alertaclient/config.py
+++ b/alertaclient/config.py
@@ -64,8 +64,8 @@ def get_remote_config(self, endpoint=None):
             r.raise_for_status()
             remote_config = r.json()
         except requests.RequestException as e:
-            raise ClientException('Failed to get config from {}. Reason: {}'.format(config_url, e))
+            raise ClientException(f'Failed to get config from {config_url}. Reason: {e}')
         except json.decoder.JSONDecodeError:
-            raise ClientException('Failed to get config from {}: Reason: not a JSON object'.format(config_url))
+            raise ClientException(f'Failed to get config from {config_url}: Reason: not a JSON object')
 
         self.options = {**remote_config, **self.options}
diff --git a/alertaclient/models/blackout.py b/alertaclient/models/blackout.py
index 8323dea..856f0ce 100644
--- a/alertaclient/models/blackout.py
+++ b/alertaclient/models/blackout.py
@@ -129,9 +129,9 @@ def tabular(self, timezone=None):
             'customer': self.customer,
             'startTime': DateTime.localtime(self.start_time, timezone),
             'endTime': DateTime.localtime(self.end_time, timezone),
-            'duration': '{}s'.format(self.duration),
+            'duration': f'{self.duration}s',
             'status': self.status,
-            'remaining': '{}s'.format(self.remaining),
+            'remaining': f'{self.remaining}s',
             'user': self.user,
             'createTime': DateTime.localtime(self.create_time, timezone),
             'text': self.text
diff --git a/alertaclient/models/enums.py b/alertaclient/models/enums.py
index 46eb45c..5eff97b 100644
--- a/alertaclient/models/enums.py
+++ b/alertaclient/models/enums.py
@@ -55,7 +55,7 @@ def from_str(action: str, resource: str = None):
         :return: Scope
         """
         if resource:
-            return Scope('{}:{}'.format(action, resource))
+            return Scope(f'{action}:{resource}')
         else:
             return Scope(action)
 
diff --git a/alertaclient/models/heartbeat.py b/alertaclient/models/heartbeat.py
index 4b8f56f..1f13809 100644
--- a/alertaclient/models/heartbeat.py
+++ b/alertaclient/models/heartbeat.py
@@ -70,8 +70,8 @@ def tabular(self, timezone=None):
             'createTime': DateTime.localtime(self.create_time, timezone),
             'receiveTime': DateTime.localtime(self.receive_time, timezone),
             'since': self.since,
-            'timeout': '{}s'.format(self.timeout),
-            'latency': '{:.0f}ms'.format(self.latency),
-            'maxLatency': '{}ms'.format(self.max_latency),
+            'timeout': f'{self.timeout}s',
+            'latency': f'{self.latency:.0f}ms',
+            'maxLatency': f'{self.max_latency}ms',
             'status': self.status
         }
diff --git a/alertaclient/top.py b/alertaclient/top.py
index c3756fe..702dc51 100644
--- a/alertaclient/top.py
+++ b/alertaclient/top.py
@@ -84,7 +84,7 @@ def update(self):
 
         # draw header
         self._addstr(0, 0, self.client.endpoint, curses.A_BOLD)
-        self._addstr(0, 'C', 'alerta {}'.format(version), curses.A_BOLD)
+        self._addstr(0, 'C', f'alerta {version}', curses.A_BOLD)
         self._addstr(0, 'R', '{}'.format(now.strftime('%H:%M:%S %d/%m/%y')), curses.A_BOLD)
 
         # TODO - draw bars
diff --git a/alertaclient/utils.py b/alertaclient/utils.py
index 12549d7..9577073 100644
--- a/alertaclient/utils.py
+++ b/alertaclient/utils.py
@@ -50,7 +50,7 @@ def action_progressbar(client, action, ids, label, text=None, timeout=None):
 
     def show_skipped(id):
         if not id and skipped:
-            return '(skipped {})'.format(skipped)
+            return f'(skipped {skipped})'
 
     with click.progressbar(ids, label=label, show_eta=True, item_show_func=show_skipped) as bar:
         for id in bar:
@@ -62,4 +62,4 @@ def show_skipped(id):
 
 def origin():
     prog = os.path.basename(sys.argv[0])
-    return '{}/{}'.format(prog, platform.uname()[1])
+    return f'{prog}/{platform.uname()[1]}'