diff --git a/build.gradle b/build.gradle
index 464ce00a..d91b1454 100644
--- a/build.gradle
+++ b/build.gradle
@@ -19,6 +19,7 @@ dependencies {
     implementation(libs.telegram.bot.api)
     implementation(libs.tika)
 
+    testCompileOnly(libs.jspecify)
     testImplementation(libs.hamcrest)
     testImplementation(libs.junit.jupiter)
     testImplementation(libs.mockwebserver)
@@ -53,6 +54,15 @@ def jlink = tasks.register('jlink', JlinkTask) {
     description = 'Generates a minimal JRE for the project.'
 }
 
+nullability {
+    errorProneVersion = libs.errorprone.get().version
+    nullAwayVersion = libs.nullaway.get().version
+}
+
+tasks.named("compileTestJava") {
+    options.nullability.checking = "tests"
+}
+
 test {
     inputs.dir(jlink.map { it.outputDirectory.get().asFile })
     javaLauncher = providers.provider { new JlinkJavaLauncher(jlink.get()) }
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index 66bade20..a99f040f 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -1,4 +1,5 @@
 [libraries]
+errorprone = "com.google.errorprone:error_prone_core:2.42.0"
 gson = "com.google.code.gson:gson:2.13.2"
 hamcrest = "org.hamcrest:hamcrest:3.0"
 jspecify = "org.jspecify:jspecify:1.0.0"
@@ -6,8 +7,9 @@ junit-jupiter = "org.junit.jupiter:junit-jupiter:5.14.0"
 junit-platform = "org.junit.platform:junit-platform-launcher:1.14.0"
 logback-classic = "ch.qos.logback:logback-classic:1.5.18"
 mockwebserver = "com.squareup.okhttp3:mockwebserver3-junit5:5.1.0"
+nullaway = "com.uber.nullaway:nullaway:0.12.10"
 telegram-bot-api = "com.github.pengrad:java-telegram-bot-api:9.2.0"
 tika = "org.apache.tika:tika-core:3.2.3"
 
 [plugins]
-spring-nullability = "io.spring.nullability:0.0.4"
+spring-nullability = "io.spring.nullability:0.0.5"
diff --git a/src/test/java/com/github/stickerifier/stickerify/logger/LoggingEvent.java b/src/test/java/com/github/stickerifier/stickerify/logger/LoggingEvent.java
index 4663708e..250943cd 100644
--- a/src/test/java/com/github/stickerifier/stickerify/logger/LoggingEvent.java
+++ b/src/test/java/com/github/stickerifier/stickerify/logger/LoggingEvent.java
@@ -6,6 +6,7 @@
 import ch.qos.logback.classic.spi.StackTraceElementProxy;
 import ch.qos.logback.classic.spi.ThrowableProxyVO;
 import com.github.stickerifier.stickerify.exception.TelegramApiException;
+import org.jspecify.annotations.Nullable;
 
 /**
  * Test double that serves as an implementation of {@link ILoggingEvent}.
@@ -15,7 +16,7 @@ class LoggingEvent extends LoggingEventVO {
 	static final String EXCEPTION_CLASS = TelegramApiException.class.getName();
 
 	private final String formattedMessage;
-	private IThrowableProxy throwableProxy;
+	private @Nullable IThrowableProxy throwableProxy;
 
 	LoggingEvent(String formattedMessage) {
 		this.formattedMessage = formattedMessage;
@@ -54,6 +55,7 @@ public String getFormattedMessage() {
 		return formattedMessage;
 	}
 
+	@Nullable
 	@Override
 	public IThrowableProxy getThrowableProxy() {
 		return throwableProxy;
diff --git a/src/test/java/com/github/stickerifier/stickerify/media/MediaHelperTest.java b/src/test/java/com/github/stickerifier/stickerify/media/MediaHelperTest.java
index e09afc86..5aa342aa 100644
--- a/src/test/java/com/github/stickerifier/stickerify/media/MediaHelperTest.java
+++ b/src/test/java/com/github/stickerifier/stickerify/media/MediaHelperTest.java
@@ -21,6 +21,7 @@
 import com.github.stickerifier.stickerify.junit.ClearTempFiles;
 import com.github.stickerifier.stickerify.junit.Tags;
 import com.github.stickerifier.stickerify.process.ProcessHelper;
+import org.jspecify.annotations.Nullable;
 import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Nested;
 import org.junit.jupiter.api.Tag;
@@ -45,7 +46,9 @@ void resizeRectangularImage() throws Exception {
 		assertImageConsistency(result, 512, 341);
 	}
 
-	private static void assertImageConsistency(File image, int expectedWidth, int expectedHeight) throws Exception {
+	private static void assertImageConsistency(@Nullable File image, int expectedWidth, int expectedHeight) throws Exception {
+		assertNotNull(image);
+
 		var mediaInfo = MediaHelper.retrieveMultimediaInfo(image);
 		var imageInfo = mediaInfo.video();
 		assertNotNull(imageInfo);
@@ -154,7 +157,9 @@ void convertLongMovVideo() throws Exception {
 		assertVideoConsistency(result, 512, 288, 29.97003F, 2.969F);
 	}
 
-	private static void assertVideoConsistency(File video, int expectedWidth, int expectedHeight, float expectedFrameRate, float expectedDuration) throws Exception {
+	private static void assertVideoConsistency(@Nullable File video, int expectedWidth, int expectedHeight, float expectedFrameRate, float expectedDuration) throws Exception {
+		assertNotNull(video);
+
 		var mediaInfo = MediaHelper.retrieveMultimediaInfo(video);
 		var videoInfo = mediaInfo.video();
 		assertNotNull(videoInfo);