diff --git a/lib/Service/FetchCurrenciesService.php b/lib/Service/FetchCurrenciesService.php
index 6a34fcb..eb87004 100644
--- a/lib/Service/FetchCurrenciesService.php
+++ b/lib/Service/FetchCurrenciesService.php
@@ -21,6 +21,7 @@ use OCA\AutoCurrency\Db\CustomCurrency;
 use OCA\AutoCurrency\Db\CustomCurrencyMapper;
 use OCP\AppFramework\Db\DoesNotExistException;
 use OCP\AppFramework\Db\MultipleObjectsReturnedException;
+use OCP\Http\Client\IClientService;
 use OCP\IAppConfig;
 
 use Psr\Log\LoggerInterface;
@@ -60,6 +61,7 @@ class FetchCurrenciesService {
 		private CospendProjectMapper $projectMapper,
 		private AutocurrencyRateHistoryMapper $historyMapper,
 		private CustomCurrencyMapper $customCurrencyMapper,
+		private IClientService $clientService,
 		private LoggerInterface $logger,
 	) {
 		$this->config = $config;
@@ -67,6 +69,7 @@ class FetchCurrenciesService {
 		$this->projectMapper = $projectMapper;
 		$this->historyMapper = $historyMapper;
 		$this->customCurrencyMapper = $customCurrencyMapper;
+		$this->clientService = $clientService;
 		$this->logger = $logger;
 		$this->loadSymbols();
 	}
@@ -189,23 +192,18 @@ class FetchCurrenciesService {
 		$this->logger->info('Fetching exchange rates for base currency ' . $baseCurrency);
 		$url = $this->replaceTokens(self::$EXCHANGE_URL, $baseCurrency);
 
-		$fp = @fopen($url, 'r');
-		if (!$fp) {
-			$err = error_get_last();
-			throw new \RuntimeException("Failed to open URL: $url — " . ($err['message'] ?? 'unknown error'));
-		}
+		$client = $this->clientService->newClient();
+		$response = $client->get($url);
+		$data = $response->getBody();
 
-		$data = stream_get_contents($fp);
-		fclose($fp);
-
-		if ($data === false || $data === '') {
-			throw new \RuntimeException("Empty response from URL: $url");
+		if ($data === '') {
+			throw new \RuntimeException("Empty response from URL: $url (HTTP " . $response->getStatusCode() . ')');
 		}
 
 		$json = json_decode($data, true);
 
 		if ($json === null) {
-			throw new \RuntimeException("Invalid JSON from $url (first 200 chars): " . substr($data, 0, 200));
+			throw new \RuntimeException("Invalid JSON from $url (HTTP " . $response->getStatusCode() . ', first 200 chars): ' . substr($data, 0, 200));
 		}
 
 		if (!isset($json[$baseCurrency])) {
@@ -322,37 +320,24 @@ class FetchCurrenciesService {
 
 		$this->logger->debug("Fetching API response from: $url");
 
-		// Set up stream context with headers if API key is provided
-		$opts = [
-			'http' => [
-				'method' => 'GET',
-				'header' => '',
-			],
-		];
-
+		$options = [];
 		if ($apiKey && $apiKey !== '') {
-			$opts['http']['header'] = "Authorization: Bearer $apiKey\r\n";
+			$options['headers'] = ['Authorization' => "Bearer $apiKey"];
 			$this->logger->debug('Using API key for authentication');
 		}
 
-		$context = stream_context_create($opts);
-		$fp = @fopen($url, 'r', false, $context);
-		if (!$fp) {
-			$err = error_get_last();
-			throw new \RuntimeException("Failed to open URL: $url — " . ($err['message'] ?? 'unknown error'));
-		}
+		$client = $this->clientService->newClient();
+		$response = $client->get($url, $options);
+		$data = $response->getBody();
 
-		$data = stream_get_contents($fp);
-		fclose($fp);
-
-		if ($data === false || $data === '') {
-			throw new \RuntimeException("Empty response from URL: $url");
+		if ($data === '') {
+			throw new \RuntimeException("Empty response from URL: $url (HTTP " . $response->getStatusCode() . ')');
 		}
 
 		$json = json_decode($data, true);
 
 		if ($json === null) {
-			throw new \RuntimeException("Failed to decode JSON from $url (first 200 chars): " . substr($data, 0, 200));
+			throw new \RuntimeException("Failed to decode JSON from $url (HTTP " . $response->getStatusCode() . ', first 200 chars): ' . substr($data, 0, 200));
 		}
 
 		$this->apiCache[$cacheKey] = $json;
diff --git a/tests/unit/Controller/ApiControllerTest.php b/tests/unit/Controller/ApiControllerTest.php
index eac8bb2..0757c56 100644
--- a/tests/unit/Controller/ApiControllerTest.php
+++ b/tests/unit/Controller/ApiControllerTest.php
@@ -40,6 +40,7 @@ use OCA\AutoCurrency\Db\CustomCurrency;
 use OCA\AutoCurrency\Db\CustomCurrencyMapper;
 use OCA\AutoCurrency\Service\FetchCurrenciesService;
 use OCA\Cospend\Db\Project;
+use OCP\Http\Client\IClientService;
 use OCP\IAppConfig;
 use OCP\IL10N;
 use OCP\IRequest;
@@ -87,10 +88,11 @@ final class ApiControllerTest extends TestCase {
 		$this->logger = $opts['logger'] ?? $this->createMock(LoggerInterface::class);
 
 		$this->customCurrencyMapper->method('findAll')->willReturn([]);
+		$clientService = $this->createMock(IClientService::class);
 
 		if (!empty($opts['serviceMethods'])) {
 			$this->service = $this->getMockBuilder(FetchCurrenciesService::class)
-				->setConstructorArgs([$this->config, $this->currencyMapper, $this->projectMapper, $this->historyMapper, $this->customCurrencyMapper, $this->logger])
+				->setConstructorArgs([$this->config, $this->currencyMapper, $this->projectMapper, $this->historyMapper, $this->customCurrencyMapper, $clientService, $this->logger])
 				->onlyMethods($opts['serviceMethods'])
 				->getMock();
 		} else {
@@ -100,6 +102,7 @@ final class ApiControllerTest extends TestCase {
 				$this->projectMapper,
 				$this->historyMapper,
 				$this->customCurrencyMapper,
+				$clientService,
 				$this->logger
 			);
 		}
diff --git a/tests/unit/Service/FetchCurrenciesServiceTest.php b/tests/unit/Service/FetchCurrenciesServiceTest.php
index 3673264..37dedab 100644
--- a/tests/unit/Service/FetchCurrenciesServiceTest.php
+++ b/tests/unit/Service/FetchCurrenciesServiceTest.php
@@ -13,6 +13,7 @@ use OCA\AutoCurrency\Db\CurrencyMapper;
 use OCA\AutoCurrency\Db\CustomCurrency;
 use OCA\AutoCurrency\Db\CustomCurrencyMapper;
 use OCA\AutoCurrency\Service\FetchCurrenciesService;
+use OCP\Http\Client\IClientService;
 use OCP\IAppConfig;
 use PHPUnit\Framework\TestCase;
 use Psr\Log\LoggerInterface;
@@ -27,6 +28,7 @@ final class FetchCurrenciesServiceTest extends TestCase {
 		$projectMapper = $this->createMock(CospendProjectMapper::class);
 		$historyMapper = $this->createMock(AutocurrencyRateHistoryMapper::class);
 		$customCurrencyMapper = $this->createMock(CustomCurrencyMapper::class);
+		$clientService = $this->createMock(IClientService::class);
 		$logger = $this->createMock(LoggerInterface::class);
 
 		$customCurrencyMapper->method('findAll')->willReturn([]);
@@ -37,6 +39,7 @@ final class FetchCurrenciesServiceTest extends TestCase {
 			$projectMapper,
 			$historyMapper,
 			$customCurrencyMapper,
+			$clientService,
 			$logger
 		);