diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,17 @@
+## <small>0.7.0 (2024-06-24)</small>
+
+* Format all ([0910331](https://github.com/finn-no/unleash-client-haskell/commit/0910331))
+* Reformat flake.nix ([42cd35a](https://github.com/finn-no/unleash-client-haskell/commit/42cd35a))
+* Relax mtl and servant-* constraints ([82f3e1f](https://github.com/finn-no/unleash-client-haskell/commit/82f3e1f))
+* Simplify isEnabled and add isEnabledWithContext ([6d67d38](https://github.com/finn-no/unleash-client-haskell/commit/6d67d38))
+* Support custom strategies (#12) ([bf56170](https://github.com/finn-no/unleash-client-haskell/commit/bf56170)), closes [#12](https://github.com/finn-no/unleash-client-haskell/issues/12)
+* unleash-client-haskell-core: 0.11.0 ([1685750](https://github.com/finn-no/unleash-client-haskell/commit/1685750))
+* Update flake-compat ([4fcfc9a](https://github.com/finn-no/unleash-client-haskell/commit/4fcfc9a))
+* Update nixpkgs ([0498877](https://github.com/finn-no/unleash-client-haskell/commit/0498877))
+* Update unleash-client-haskell-core ([f147f09](https://github.com/finn-no/unleash-client-haskell/commit/f147f09))
+
+
+
 ## <small>0.6.0 (2023-10-16)</small>
 
 * Set version to 0.6.0 ([925b4f6](https://github.com/finn-no/unleash-client-haskell/commit/925b4f6))
diff --git a/example/Main.hs b/example/Main.hs
--- a/example/Main.hs
+++ b/example/Main.hs
@@ -18,7 +18,6 @@
 import Data.Void (Void)
 import Servant.Client (BaseUrl (BaseUrl), Scheme (Http))
 import System.Exit (die)
-import Unleash (emptyContext)
 import Unleash.Client (
     HasUnleash (..),
     UnleashConfig (..),
@@ -60,7 +59,7 @@
 application :: Program Void
 application =
     forever do
-        enabled <- isEnabled featureToggle emptyContext
+        enabled <- isEnabled featureToggle
         liftIO . putStrLn $ T.unpack featureToggle <> " is " <> (if enabled then "enabled" else "disabled")
         liftIO . threadDelay $ 2 * 1000 * 1000
 
diff --git a/src/Unleash/Client.hs b/src/Unleash/Client.hs
--- a/src/Unleash/Client.hs
+++ b/src/Unleash/Client.hs
@@ -13,15 +13,23 @@
     UnleashConfig (..),
     HasUnleash (..),
     registerClient,
+    registerClientWithCustomStrategies,
     pollToggles,
+    pollTogglesWithCustomStrategies,
     pushMetrics,
     isEnabled,
+    isEnabledWithContext,
     tryIsEnabled,
+    tryIsEnabledWithContext,
     getVariant,
     tryGetVariant,
     -- Re-exports
     Context (..),
     emptyContext,
+    FeatureToggleName,
+    Strategy (..),
+    StrategyEvaluator,
+    SupportedStrategies,
     VariantResponse (..),
 ) where
 
@@ -33,12 +41,28 @@
 import Data.Time (UTCTime, getCurrentTime)
 import Network.HTTP.Client.TLS (newTlsManager)
 import Servant.Client (BaseUrl, ClientEnv, ClientError, mkClientEnv)
-import Unleash (Context (..), Features, MetricsPayload (..), RegisterPayload (..), VariantResponse (..), emptyContext, emptyVariantResponse, featureGetVariant, featureIsEnabled)
+import Unleash (
+    Context (..),
+    FeatureToggleName,
+    Features,
+    MetricsPayload (..),
+    RegisterPayload (..),
+    Strategy (..),
+    StrategyEvaluator,
+    SupportedStrategies,
+    VariantResponse (..),
+    defaultStrategyEvaluator,
+    defaultSupportedStrategies,
+    emptyContext,
+    emptyVariantResponse,
+    featureGetVariant,
+    featureIsEnabled,
+ )
 import Unleash.Internal.HttpClient (getAllClientFeatures, register, sendMetrics)
 
 -- | Smart constructor for Unleash client configuration. Initializes the mutable variables properly.
 makeUnleashConfig ::
-    MonadIO m =>
+    (MonadIO m) =>
     -- | Application name.
     Text ->
     -- | Instance identifier.
@@ -96,7 +120,11 @@
 
 -- | Register client for the Unleash server. Call this on application startup before calling the state poller and metrics pusher functions.
 registerClient :: (HasUnleash r, MonadReader r m, MonadIO m) => m (Either ClientError ())
-registerClient = do
+registerClient = registerClientWithCustomStrategies defaultSupportedStrategies
+
+-- | Register client for the Unleash server. Custom strategies are added to default strategies. Call this on application startup before calling the state poller and metrics pusher functions.
+registerClientWithCustomStrategies :: (HasUnleash r, MonadReader r m, MonadIO m) => SupportedStrategies -> m (Either ClientError ())
+registerClientWithCustomStrategies customSupportedStrategies = do
     config <- asks getUnleashConfig
     now <- liftIO getCurrentTime
     let registrationPayload :: RegisterPayload
@@ -104,6 +132,7 @@
             RegisterPayload
                 { appName = config.applicationName,
                   instanceId = config.instanceId,
+                  strategies = defaultSupportedStrategies <> customSupportedStrategies,
                   started = now,
                   intervalSeconds = config.metricsPushIntervalInSeconds
                 }
@@ -111,16 +140,28 @@
 
 -- | Fetch the most recent feature toggle set from the Unleash server. Meant to be run every statePollIntervalInSeconds. Non-blocking.
 pollToggles :: (HasUnleash r, MonadReader r m, MonadIO m) => m (Either ClientError ())
-pollToggles = do
+pollToggles = pollTogglesWithCustomStrategies defaultStrategyEvaluator
+
+-- | Fetch the most recent feature toggle set from the Unleash server. Custom strategies are added to default strategies. Meant to be run every statePollIntervalInSeconds. Non-blocking.
+pollTogglesWithCustomStrategies :: (HasUnleash r, MonadReader r m, MonadIO m) => StrategyEvaluator -> m (Either ClientError ())
+pollTogglesWithCustomStrategies customStrategyEvaluator = do
     config <- asks getUnleashConfig
-    eitherFeatures <- getAllClientFeatures config.httpClientEnvironment config.apiKey
+    eitherFeatures <- getAllClientFeatures config.httpClientEnvironment strategyEvaluator config.apiKey
     either (const $ pure ()) (updateState config.state) eitherFeatures
     pure . void $ eitherFeatures
     where
+        strategyEvaluator :: StrategyEvaluator
+        strategyEvaluator = withCustomStrategyEvaluator customStrategyEvaluator
         updateState state value = do
             isUpdated <- liftIO $ tryPutMVar state value
             liftIO . unless isUpdated . void $ swapMVar state value
 
+withCustomStrategyEvaluator :: StrategyEvaluator -> StrategyEvaluator
+withCustomStrategyEvaluator customStrategyEvaluator featureToggleName jsonStrategy ctx = do
+    defaultResult <- defaultStrategyEvaluator featureToggleName jsonStrategy ctx
+    customResult <- customStrategyEvaluator featureToggleName jsonStrategy ctx
+    pure $ defaultResult || customResult
+
 -- | Push metrics to the Unleash server. Meant to be run every metricsPushIntervalInSeconds. Blocks if the mutable metrics variables are empty.
 pushMetrics :: (HasUnleash r, MonadReader r m, MonadIO m) => m (Either ClientError ())
 pushMetrics = do
@@ -144,10 +185,19 @@
     -- | Feature toggle name.
     Text ->
     -- | Client context.
+    m Bool
+isEnabled feature = isEnabledWithContext feature emptyContext
+
+-- | Check if a feature is enabled or not. Blocks until first feature toggle set is received. Blocks if the mutable metrics variables are empty.
+isEnabledWithContext ::
+    (HasUnleash r, MonadReader r m, MonadIO m) =>
+    -- | Feature toggle name.
+    Text ->
+    -- | Client context.
     Context ->
     -- | Whether or not the feature toggle is enabled.
     m Bool
-isEnabled feature context = do
+isEnabledWithContext feature context = do
     config <- asks getUnleashConfig
     state <- liftIO . readMVar $ config.state
     enabled <- featureIsEnabled state feature context
@@ -160,10 +210,19 @@
     -- | Feature toggle name.
     Text ->
     -- | Client context.
+    m Bool
+tryIsEnabled feature = tryIsEnabledWithContext feature emptyContext
+
+-- | Check if a feature is enabled or not. Returns false for all toggles until first toggle set is received. Blocks if the mutable metrics variables are empty.
+tryIsEnabledWithContext ::
+    (HasUnleash r, MonadReader r m, MonadIO m) =>
+    -- | Feature toggle name.
+    Text ->
+    -- | Client context.
     Context ->
     -- | Whether or not the feature toggle is enabled.
     m Bool
-tryIsEnabled feature context = do
+tryIsEnabledWithContext feature context = do
     config <- asks getUnleashConfig
     maybeState <- liftIO . tryReadMVar $ config.state
     case maybeState of
diff --git a/src/Unleash/Internal/HttpClient.hs b/src/Unleash/Internal/HttpClient.hs
--- a/src/Unleash/Internal/HttpClient.hs
+++ b/src/Unleash/Internal/HttpClient.hs
@@ -22,7 +22,8 @@
 import Paths_unleash_client_haskell (version)
 import Servant.API (Accept (contentTypes), Get, Header, JSON, MimeRender (mimeRender), NoContent, PostNoContent, ReqBody, type (:<|>) (..), type (:>))
 import Servant.Client (ClientEnv, ClientError, client, runClientM)
-import Unleash.Internal.DomainTypes (Features, fromJsonFeatures, supportedStrategies)
+import Unleash (Features, StrategyEvaluator)
+import Unleash.Internal.DomainTypes (fromJsonFeatures)
 import Unleash.Internal.JsonTypes (FullMetricsBucket (..), FullMetricsPayload (..), FullRegisterPayload (..), MetricsPayload, RegisterPayload, YesAndNoes (..))
 import qualified Unleash.Internal.JsonTypes as UJT
 
@@ -46,28 +47,28 @@
         "application" M.// "json"
             NE.:| ["application" M.// "json"]
 
-instance {-# OVERLAPPABLE #-} ToJSON a => MimeRender CustomJSON a where
+instance {-# OVERLAPPABLE #-} (ToJSON a) => MimeRender CustomJSON a where
     mimeRender _ = encode
 
-register :: MonadIO m => ClientEnv -> Maybe ApiKey -> RegisterPayload -> m (Either ClientError NoContent)
+register :: (MonadIO m) => ClientEnv -> Maybe ApiKey -> RegisterPayload -> m (Either ClientError NoContent)
 register clientEnv apiKey registerPayload = do
     let fullRegisterPayload =
             FullRegisterPayload
                 { appName = registerPayload.appName,
                   instanceId = registerPayload.instanceId,
                   sdkVersion = "unleash-client-haskell:" <> (T.pack . showVersion) version,
-                  strategies = supportedStrategies,
+                  strategies = registerPayload.strategies,
                   started = registerPayload.started,
                   interval = registerPayload.intervalSeconds * 1000
                 }
     liftIO $ runClientM (register' apiKey (Just "application/json") fullRegisterPayload) clientEnv
 
-getAllClientFeatures :: MonadIO m => ClientEnv -> Maybe ApiKey -> m (Either ClientError Features)
-getAllClientFeatures clientEnv apiKey = do
+getAllClientFeatures :: (MonadIO m) => ClientEnv -> StrategyEvaluator -> Maybe ApiKey -> m (Either ClientError Features)
+getAllClientFeatures clientEnv strategyEvaluator apiKey = do
     eitherFeatures <- liftIO $ runClientM (getAllClientFeatures' apiKey) clientEnv
-    pure $ fromJsonFeatures <$> eitherFeatures
+    pure $ fromJsonFeatures strategyEvaluator <$> eitherFeatures
 
-sendMetrics :: MonadIO m => ClientEnv -> Maybe ApiKey -> MetricsPayload -> m (Either ClientError NoContent)
+sendMetrics :: (MonadIO m) => ClientEnv -> Maybe ApiKey -> MetricsPayload -> m (Either ClientError NoContent)
 sendMetrics clientEnv apiKey metricsPayload = do
     liftIO $ runClientM (sendMetrics' apiKey fullMetricsPayload) clientEnv
     where
diff --git a/unleash-client-haskell.cabal b/unleash-client-haskell.cabal
--- a/unleash-client-haskell.cabal
+++ b/unleash-client-haskell.cabal
@@ -1,7 +1,7 @@
 cabal-version: 3.0
 
 name: unleash-client-haskell
-version: 0.6.0
+version: 0.7.0
 synopsis: Unleash feature toggle client
 description:
     This is an [Unleash](https://www.getunleash.io/) client SDK for Haskell.
@@ -65,14 +65,14 @@
         aeson >= 2.0.3 && < 2.2,
         base >= 4.7 && < 5,
         containers >= 0.6.4 && < 0.7,
-        mtl >= 2.2.2 && < 2.3,
+        mtl >= 2.2.2 && < 2.4,
         text >= 1.2.5 && < 2.1,
         time >= 1.9.3 && < 1.13,
         http-client-tls >= 0.3.6 && < 0.4,
         http-media >= 0.8.0 && < 0.9,
-        servant >= 0.19.1 && < 0.20,
-        servant-client >= 0.19 && < 0.20,
-        unleash-client-haskell-core >= 0.8.7 && < 0.11,
+        servant >= 0.19.1 && < 0.21,
+        servant-client >= 0.19 && < 0.21,
+        unleash-client-haskell-core >= 0.11.0 && < 0.12,
 
 executable example
     import: all
@@ -85,4 +85,3 @@
         servant-client,
         text,
         unleash-client-haskell,
-        unleash-client-haskell-core,