diff --git a/app/build.gradle.kts b/app/build.gradle.kts
index ef734b56..24dca25a 100644
--- a/app/build.gradle.kts
+++ b/app/build.gradle.kts
@@ -212,6 +212,8 @@ ksp {
 }
 
 dependencies {
+    lintChecks(project(":lint-rules"))
+
     implementation(libs.quartz) {
         exclude(group = "net.java.dev.jna")
     }
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index 08ae52fc..0b9d7ba2 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -33,6 +33,8 @@ coroutinesTest = "1.11.0"
 kmpTor = "2.6.0"
 kmpTorResource = "409.5.0"
 secp256k1Jni = "0.23.0"
+# Android Lint API version follows AGP: lint = agp major + 23
+lintApi = "32.2.1"
 
 [libraries]
 datastore-preferences = { module = "androidx.datastore:datastore-preferences", version.ref = "datastorePreferences" }
@@ -80,6 +82,7 @@ paging-compose = { group = "androidx.paging", name = "paging-compose", version.r
 paging-runtime = { group = "androidx.paging", name = "paging-runtime", version.ref = "pagingCommon" }
 mockk = { module = "io.mockk:mockk", version.ref = "mockk" }
 kotlinx-coroutines-test = { module = "org.jetbrains.kotlinx:kotlinx-coroutines-test", version.ref = "coroutinesTest" }
+lint-api = { module = "com.android.tools.lint:lint-api", version.ref = "lintApi" }
 kmptor-runtime = { module = "io.matthewnelson.kmp-tor:runtime", version.ref = "kmpTor" }
 kmptor-resource-exec = { module = "io.matthewnelson.kmp-tor:resource-exec-tor", version.ref = "kmpTorResource" }
 secp256k1-jni-jvm = { module = "fr.acinq.secp256k1:secp256k1-kmp-jni-jvm", version.ref = "secp256k1Jni" }
diff --git a/lint-rules/build.gradle.kts b/lint-rules/build.gradle.kts
new file mode 100644
index 00000000..a5da4a91
--- /dev/null
+++ b/lint-rules/build.gradle.kts
@@ -0,0 +1,24 @@
+plugins {
+    // No version: AGP's built-in Kotlin already puts the plugin on the build classpath
+    id("org.jetbrains.kotlin.jvm")
+    alias(libs.plugins.gradle.ktlint) version libs.versions.ktlint.get()
+}
+
+java {
+    sourceCompatibility = JavaVersion.VERSION_21
+    targetCompatibility = JavaVersion.VERSION_21
+}
+
+kotlin {
+    jvmToolchain(21)
+}
+
+dependencies {
+    compileOnly(libs.lint.api)
+}
+
+tasks.jar {
+    manifest {
+        attributes("Lint-Registry-v2" to "com.greenart7c3.nostrsigner.lint.AmberIssueRegistry")
+    }
+}
diff --git a/lint-rules/src/main/java/com/greenart7c3/nostrsigner/lint/AmberIssueRegistry.kt b/lint-rules/src/main/java/com/greenart7c3/nostrsigner/lint/AmberIssueRegistry.kt
new file mode 100644
index 00000000..83bb708c
--- /dev/null
+++ b/lint-rules/src/main/java/com/greenart7c3/nostrsigner/lint/AmberIssueRegistry.kt
@@ -0,0 +1,19 @@
+package com.greenart7c3.nostrsigner.lint
+
+import com.android.tools.lint.client.api.IssueRegistry
+import com.android.tools.lint.client.api.Vendor
+import com.android.tools.lint.detector.api.CURRENT_API
+import com.android.tools.lint.detector.api.Issue
+
+class AmberIssueRegistry : IssueRegistry() {
+    override val issues: List<Issue> = listOf(
+        LongToDurationDetector.ISSUE,
+    )
+
+    override val api: Int = CURRENT_API
+
+    override val vendor: Vendor = Vendor(
+        vendorName = "Amber",
+        feedbackUrl = "https://github.com/greenart7c3/Amber/issues",
+    )
+}
diff --git a/lint-rules/src/main/java/com/greenart7c3/nostrsigner/lint/LongToDurationDetector.kt b/lint-rules/src/main/java/com/greenart7c3/nostrsigner/lint/LongToDurationDetector.kt
new file mode 100644
index 00000000..d4fc4ba6
--- /dev/null
+++ b/lint-rules/src/main/java/com/greenart7c3/nostrsigner/lint/LongToDurationDetector.kt
@@ -0,0 +1,90 @@
+package com.greenart7c3.nostrsigner.lint
+
+import com.android.tools.lint.detector.api.Category
+import com.android.tools.lint.detector.api.Detector
+import com.android.tools.lint.detector.api.Implementation
+import com.android.tools.lint.detector.api.Issue
+import com.android.tools.lint.detector.api.JavaContext
+import com.android.tools.lint.detector.api.Scope
+import com.android.tools.lint.detector.api.Severity
+import com.android.tools.lint.detector.api.SourceCodeScanner
+import com.intellij.psi.PsiMethod
+import com.intellij.psi.PsiTypes
+import org.jetbrains.kotlin.analysis.api.analyze
+import org.jetbrains.kotlin.analysis.api.types.KaClassType
+import org.jetbrains.kotlin.psi.KtExpression
+import org.jetbrains.uast.UCallExpression
+
+/**
+ * Build-time port of Android Studio's "Long overload to Duration conversion" IDE
+ * inspection (ConvertLongToDurationInspection), which only runs inside the IDE.
+ * Flags calls that resolve to the legacy Long-millisecond overloads of the
+ * kotlinx.coroutines timing functions so they get migrated to the
+ * kotlin.time.Duration overloads.
+ */
+class LongToDurationDetector :
+    Detector(),
+    SourceCodeScanner {
+    override fun getApplicableMethodNames(): List<String> = listOf(
+        "delay",
+        "withTimeout",
+        "withTimeoutOrNull",
+        "debounce",
+        "sample",
+        "throttle",
+        "timeout",
+        "onTimeout",
+        "advanceTimeBy",
+    )
+
+    override fun visitMethodCall(context: JavaContext, node: UCallExpression, method: PsiMethod) {
+        val packageName = context.evaluator.getPackage(method)?.qualifiedName ?: return
+        if (!packageName.startsWith("kotlinx.coroutines")) return
+        // The legacy overloads take the time value as a Long. Duration is a value
+        // class backed by a JVM long, so the Duration overloads erase to the same
+        // JVM signature and PSI resolution cannot tell them apart — classify by the
+        // Kotlin type of the argument at the call site instead.
+        if (method.parameterList.parameters.none { it.type == PsiTypes.longType() }) return
+        for (argument in node.valueArguments) {
+            val ktExpression = argument.sourcePsi as? KtExpression ?: continue
+            val argumentClassFqName = try {
+                analyze(ktExpression) {
+                    (ktExpression.expressionType as? KaClassType)?.classId?.asFqNameString()
+                }
+            } catch (_: Throwable) {
+                // Analysis session unavailable — cannot classify the overload
+                return
+            }
+            when (argumentClassFqName) {
+                // Already migrated to the Duration overload
+                "kotlin.time.Duration" -> return
+                "kotlin.Long", "kotlin.Int" -> {
+                    context.report(
+                        ISSUE,
+                        node,
+                        context.getCallLocation(node, includeReceiver = false, includeArguments = true),
+                        "Legacy `Long` overload can be converted to `Duration`",
+                    )
+                    return
+                }
+            }
+        }
+    }
+
+    companion object {
+        val ISSUE = Issue.create(
+            id = "LongToDuration",
+            briefDescription = "Legacy Long overload can be converted to Duration",
+            explanation = """
+                kotlinx.coroutines timing functions (`delay`, `withTimeout`, `debounce`, …) \
+                have `kotlin.time.Duration` overloads that are preferred over the legacy \
+                Long-millisecond overloads. Replace e.g. `delay(3000)` with \
+                `delay(3.seconds)` using `kotlin.time.Duration.Companion` extensions.
+            """,
+            category = Category.CORRECTNESS,
+            priority = 5,
+            severity = Severity.WARNING,
+            implementation = Implementation(LongToDurationDetector::class.java, Scope.JAVA_FILE_SCOPE),
+        )
+    }
+}
diff --git a/settings.gradle.kts b/settings.gradle.kts
index b5119ecd..396a96d3 100644
--- a/settings.gradle.kts
+++ b/settings.gradle.kts
@@ -17,3 +17,4 @@ dependencyResolutionManagement {
 }
 rootProject.name = "Nostr Signer"
 include(":app")
+include(":lint-rules")