diff --git a/src/Command/ImportModListsCommand.php b/src/Command/ImportModListsCommand.php
index 661a02b3..3fc4a681 100644
--- a/src/Command/ImportModListsCommand.php
+++ b/src/Command/ImportModListsCommand.php
@@ -4,7 +4,7 @@
 
 namespace App\Command;
 
-use App\Service\LegacyModListImport\ModListImport;
+use App\Service\LegacyModListImport\ModListImportInterface;
 use Symfony\Component\Console\Command\Command;
 use Symfony\Component\Console\Input\InputArgument;
 use Symfony\Component\Console\Input\InputInterface;
@@ -13,7 +13,7 @@
 class ImportModListsCommand extends Command
 {
     public function __construct(
-        private ModListImport $modListImport
+        private ModListImportInterface $modListImport
     ) {
         parent::__construct();
     }
diff --git a/src/Controller/HomeController.php b/src/Controller/HomeController.php
index 2f760c23..4d62b008 100644
--- a/src/Controller/HomeController.php
+++ b/src/Controller/HomeController.php
@@ -4,7 +4,7 @@
 
 namespace App\Controller;
 
-use App\Service\Mission\MissionClient;
+use App\Service\Mission\MissionClientInterface;
 use Psr\Log\LoggerInterface;
 use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
 use Symfony\Component\HttpFoundation\Response;
@@ -16,7 +16,7 @@
 class HomeController extends AbstractController
 {
     public function __construct(
-        private MissionClient $missionClient,
+        private MissionClientInterface $missionClient,
         private LoggerInterface $logger
     ) {
     }
diff --git a/src/Controller/ModListPublicController.php b/src/Controller/ModListPublicController.php
index 97d022af..dc1501c3 100644
--- a/src/Controller/ModListPublicController.php
+++ b/src/Controller/ModListPublicController.php
@@ -8,7 +8,7 @@
 use App\Repository\Mod\ModRepository;
 use App\Repository\ModList\ModListRepository;
 use App\Security\Enum\PermissionsEnum;
-use App\Service\Mission\MissionClient;
+use App\Service\Mission\MissionClientInterface;
 use Psr\Log\LoggerInterface;
 use Sensio\Bundle\FrameworkExtraBundle\Configuration\IsGranted;
 use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
@@ -25,7 +25,7 @@ public function __construct(
         private LoggerInterface $logger,
         private ModRepository $modRepository,
         private ModListRepository $modListRepository,
-        private MissionClient $missionClient,
+        private MissionClientInterface $missionClient,
     ) {
     }
 
diff --git a/src/Form/Dlc/DataTransformer/DlcFormDtoDataTransformer.php b/src/Form/Dlc/DataTransformer/DlcFormDtoDataTransformer.php
index c5b2ae5d..03ac8162 100644
--- a/src/Form/Dlc/DataTransformer/DlcFormDtoDataTransformer.php
+++ b/src/Form/Dlc/DataTransformer/DlcFormDtoDataTransformer.php
@@ -10,13 +10,13 @@
 use App\Form\FormDtoInterface;
 use App\Form\RegisteredDataTransformerInterface;
 use App\Service\Steam\Helper\SteamHelper;
-use App\Service\Steam\SteamApiClient;
+use App\Service\Steam\SteamApiClientInterface;
 use Ramsey\Uuid\Uuid;
 
 class DlcFormDtoDataTransformer implements RegisteredDataTransformerInterface
 {
     public function __construct(
-        private SteamApiClient $steamApiClient
+        private SteamApiClientInterface $steamApiClient
     ) {
     }
 
diff --git a/src/Form/Mod/DataTransformer/ModFormDtoDataTransformer.php b/src/Form/Mod/DataTransformer/ModFormDtoDataTransformer.php
index 902706ed..a7608c7a 100644
--- a/src/Form/Mod/DataTransformer/ModFormDtoDataTransformer.php
+++ b/src/Form/Mod/DataTransformer/ModFormDtoDataTransformer.php
@@ -15,13 +15,13 @@
 use App\Form\Mod\Dto\ModFormDto;
 use App\Form\RegisteredDataTransformerInterface;
 use App\Service\Steam\Helper\SteamHelper;
-use App\Service\Steam\SteamApiClient;
+use App\Service\Steam\SteamApiClientInterface;
 use Ramsey\Uuid\Uuid;
 
 class ModFormDtoDataTransformer implements RegisteredDataTransformerInterface
 {
     public function __construct(
-        private SteamApiClient $steamApiClient
+        private SteamApiClientInterface $steamApiClient
     ) {
     }
 
diff --git a/src/Service/LegacyModListImport/DtoToEntityConverter.php b/src/Service/LegacyModListImport/DtoToEntityConverter.php
index cc3f7f1b..55a4b670 100644
--- a/src/Service/LegacyModListImport/DtoToEntityConverter.php
+++ b/src/Service/LegacyModListImport/DtoToEntityConverter.php
@@ -14,7 +14,7 @@
 /**
  * @see https://github.com/ArmaForces/modlist/blob/master/src/util/mods.js
  */
-class DtoToEntityConverter
+class DtoToEntityConverter implements DtoToEntityConverterInterface
 {
     public function convert(ModCsvEntryDto $modCsvEntryDto): AbstractMod
     {
diff --git a/src/Service/LegacyModListImport/DtoToEntityConverterInterface.php b/src/Service/LegacyModListImport/DtoToEntityConverterInterface.php
new file mode 100644
index 00000000..9e3494d3
--- /dev/null
+++ b/src/Service/LegacyModListImport/DtoToEntityConverterInterface.php
@@ -0,0 +1,13 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Service\LegacyModListImport;
+
+use App\Entity\Mod\AbstractMod;
+use App\Service\LegacyModListImport\Dto\ModCsvEntryDto;
+
+interface DtoToEntityConverterInterface
+{
+    public function convert(ModCsvEntryDto $modCsvEntryDto): AbstractMod;
+}
diff --git a/src/Service/LegacyModListImport/ModListCsvReader.php b/src/Service/LegacyModListImport/ModListCsvReader.php
index 88b99dd3..5243fdac 100644
--- a/src/Service/LegacyModListImport/ModListCsvReader.php
+++ b/src/Service/LegacyModListImport/ModListCsvReader.php
@@ -7,7 +7,7 @@
 use App\Service\LegacyModListImport\Dto\ModCsvEntryDto;
 use League\Csv\Reader;
 
-class ModListCsvReader
+class ModListCsvReader implements ModListCsvReaderInterface
 {
     protected const COLUMN_INDEX_ID = 0;
     protected const COLUMN_INDEX_NAME = 1;
diff --git a/src/Service/LegacyModListImport/ModListCsvReaderInterface.php b/src/Service/LegacyModListImport/ModListCsvReaderInterface.php
new file mode 100644
index 00000000..28fe93ad
--- /dev/null
+++ b/src/Service/LegacyModListImport/ModListCsvReaderInterface.php
@@ -0,0 +1,10 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Service\LegacyModListImport;
+
+interface ModListCsvReaderInterface
+{
+    public function readCsvRow(string $path, string $delimiter = ';'): \Generator;
+}
diff --git a/src/Service/LegacyModListImport/ModListImport.php b/src/Service/LegacyModListImport/ModListImport.php
index e6886762..fcff080e 100644
--- a/src/Service/LegacyModListImport/ModListImport.php
+++ b/src/Service/LegacyModListImport/ModListImport.php
@@ -13,12 +13,12 @@
 use Ramsey\Uuid\Uuid;
 use Symfony\Component\Finder\Finder;
 
-class ModListImport
+class ModListImport implements ModListImportInterface
 {
     public function __construct(
         private EntityManagerInterface $entityManager,
-        private ModListCsvReader $modListCsvReader,
-        private DtoToEntityConverter $dtoToEntityConverter,
+        private ModListCsvReaderInterface $modListCsvReader,
+        private DtoToEntityConverterInterface $dtoToEntityConverter,
         private SteamWorkshopModRepository $steamWorkshopModRepository,
         private DirectoryModRepository $directoryModRepository
     ) {
diff --git a/src/Service/LegacyModListImport/ModListImportInterface.php b/src/Service/LegacyModListImport/ModListImportInterface.php
new file mode 100644
index 00000000..23338470
--- /dev/null
+++ b/src/Service/LegacyModListImport/ModListImportInterface.php
@@ -0,0 +1,10 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Service\LegacyModListImport;
+
+interface ModListImportInterface
+{
+    public function importFromDirectory(string $path, string $extension = '.csv'): void;
+}
diff --git a/src/Service/Mission/MissionClient.php b/src/Service/Mission/MissionClient.php
index aabf2ef8..4c8955e8 100644
--- a/src/Service/Mission/MissionClient.php
+++ b/src/Service/Mission/MissionClient.php
@@ -10,7 +10,7 @@
 use Symfony\Component\HttpClient\ScopingHttpClient;
 use Symfony\Contracts\HttpClient\HttpClientInterface;
 
-class MissionClient
+class MissionClient implements MissionClientInterface
 {
     public function __construct(
         private HttpClientInterface $client,
diff --git a/src/Service/Mission/MissionClientInterface.php b/src/Service/Mission/MissionClientInterface.php
new file mode 100644
index 00000000..441308b9
--- /dev/null
+++ b/src/Service/Mission/MissionClientInterface.php
@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Service\Mission;
+
+use App\Service\Mission\Dto\MissionDto;
+
+interface MissionClientInterface
+{
+    public function getMissions(bool $includeArchive = true, int $ttl = 600): \Generator;
+
+    public function getNextUpcomingMission(): ?MissionDto;
+
+    public function getCurrentMission(): ?MissionDto;
+
+    public function getArchivedMissions(): array;
+
+    public function getUpcomingMissions(): array;
+}
diff --git a/src/Service/Steam/SteamApiClient.php b/src/Service/Steam/SteamApiClient.php
index 867dfa1d..f208a373 100644
--- a/src/Service/Steam/SteamApiClient.php
+++ b/src/Service/Steam/SteamApiClient.php
@@ -11,7 +11,7 @@
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Contracts\HttpClient\HttpClientInterface;
 
-class SteamApiClient
+class SteamApiClient implements SteamApiClientInterface
 {
     public function __construct(
         private HttpClientInterface $httpClient
diff --git a/src/Service/Steam/SteamApiClientInterface.php b/src/Service/Steam/SteamApiClientInterface.php
new file mode 100644
index 00000000..45193da4
--- /dev/null
+++ b/src/Service/Steam/SteamApiClientInterface.php
@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Service\Steam;
+
+use App\Service\Steam\Dto\AppInfoDto;
+use App\Service\Steam\Dto\WorkshopItemInfoDto;
+
+interface SteamApiClientInterface
+{
+    public function getWorkshopItemInfo(int $itemId): WorkshopItemInfoDto;
+
+    public function getAppInfo(int $appId): AppInfoDto;
+}
diff --git a/src/Service/Version/VersionProvider.php b/src/Service/Version/VersionProvider.php
index 2f34dc44..c3a58d84 100644
--- a/src/Service/Version/VersionProvider.php
+++ b/src/Service/Version/VersionProvider.php
@@ -4,7 +4,7 @@
 
 namespace App\Service\Version;
 
-class VersionProvider
+class VersionProvider implements VersionProviderInterface
 {
     public function __construct(
         private string $projectDir,
diff --git a/src/Service/Version/VersionProviderInterface.php b/src/Service/Version/VersionProviderInterface.php
new file mode 100644
index 00000000..e50b54b4
--- /dev/null
+++ b/src/Service/Version/VersionProviderInterface.php
@@ -0,0 +1,10 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Service\Version;
+
+interface VersionProviderInterface
+{
+    public function getVersion(): string;
+}
diff --git a/src/Twig/VersionExtension.php b/src/Twig/VersionExtension.php
index 35fed6ae..b8674b43 100644
--- a/src/Twig/VersionExtension.php
+++ b/src/Twig/VersionExtension.php
@@ -4,14 +4,14 @@
 
 namespace App\Twig;
 
-use App\Service\Version\VersionProvider;
+use App\Service\Version\VersionProviderInterface;
 use Twig\Extension\AbstractExtension;
 use Twig\TwigFunction;
 
 class VersionExtension extends AbstractExtension
 {
     public function __construct(
-        private VersionProvider $version
+        private VersionProviderInterface $version
     ) {
     }
 
diff --git a/src/Validator/Dlc/SteamStoreArma3DlcUrlValidator.php b/src/Validator/Dlc/SteamStoreArma3DlcUrlValidator.php
index b1658cd0..807ffa64 100644
--- a/src/Validator/Dlc/SteamStoreArma3DlcUrlValidator.php
+++ b/src/Validator/Dlc/SteamStoreArma3DlcUrlValidator.php
@@ -8,7 +8,7 @@
 use App\Service\Steam\Exception\AppNotFoundException;
 use App\Service\Steam\Helper\Exception\InvalidAppUrlFormatException;
 use App\Service\Steam\Helper\SteamHelper;
-use App\Service\Steam\SteamApiClient;
+use App\Service\Steam\SteamApiClientInterface;
 use App\Validator\AbstractValidator;
 use Doctrine\ORM\EntityManagerInterface;
 use Symfony\Component\Validator\Constraint;
@@ -20,7 +20,7 @@ class SteamStoreArma3DlcUrlValidator extends AbstractValidator
 
     public function __construct(
         EntityManagerInterface $entityManager,
-        private SteamApiClient $steamApiClient
+        private SteamApiClientInterface $steamApiClient
     ) {
         parent::__construct($entityManager);
     }
diff --git a/src/Validator/Mod/SteamWorkshopArma3ModUrlValidator.php b/src/Validator/Mod/SteamWorkshopArma3ModUrlValidator.php
index d6bf310d..c5b21e72 100644
--- a/src/Validator/Mod/SteamWorkshopArma3ModUrlValidator.php
+++ b/src/Validator/Mod/SteamWorkshopArma3ModUrlValidator.php
@@ -8,7 +8,7 @@
 use App\Service\Steam\Exception\WorkshopItemNotFoundException;
 use App\Service\Steam\Helper\Exception\InvalidWorkshopItemUrlFormatException;
 use App\Service\Steam\Helper\SteamHelper;
-use App\Service\Steam\SteamApiClient;
+use App\Service\Steam\SteamApiClientInterface;
 use App\Validator\AbstractValidator;
 use Doctrine\ORM\EntityManagerInterface;
 use Symfony\Component\Validator\Constraint;
@@ -20,7 +20,7 @@ class SteamWorkshopArma3ModUrlValidator extends AbstractValidator
 
     public function __construct(
         EntityManagerInterface $entityManager,
-        private SteamApiClient $steamApiClient
+        private SteamApiClientInterface $steamApiClient
     ) {
         parent::__construct($entityManager);
     }