diff --git a/tofhir-engine/src/main/scala/io/tofhir/engine/env/EnvironmentVariable.scala b/tofhir-engine/src/main/scala/io/tofhir/engine/env/EnvironmentVariable.scala
index 70b7c684..5f75b9d1 100644
--- a/tofhir-engine/src/main/scala/io/tofhir/engine/env/EnvironmentVariable.scala
+++ b/tofhir-engine/src/main/scala/io/tofhir/engine/env/EnvironmentVariable.scala
@@ -4,4 +4,6 @@ object EnvironmentVariable extends Enumeration {
   type EnvironmentVariable = Value
   final val FHIR_REPO_URL = Value("FHIR_REPO_URL")
   final val DATA_FOLDER_PATH= Value("DATA_FOLDER_PATH")
+  final val SOURCE_URL = Value("SOURCE_URL")
+  final val REDCAP_PROJECT_ID= Value("REDCAP_PROJECT_ID")
 }
diff --git a/tofhir-engine/src/main/scala/io/tofhir/engine/env/EnvironmentVariableResolver.scala b/tofhir-engine/src/main/scala/io/tofhir/engine/env/EnvironmentVariableResolver.scala
index e03bf208..97fe77d1 100644
--- a/tofhir-engine/src/main/scala/io/tofhir/engine/env/EnvironmentVariableResolver.scala
+++ b/tofhir-engine/src/main/scala/io/tofhir/engine/env/EnvironmentVariableResolver.scala
@@ -1,6 +1,6 @@
 package io.tofhir.engine.env
 
-import io.tofhir.engine.model.{FhirMappingJob, FhirRepositorySinkSettings, FhirSinkSettings, FileSystemSourceSettings, MappingJobSourceSettings}
+import io.tofhir.engine.model.{FhirMappingJob, FhirMappingTask, FhirRepositorySinkSettings, FhirSinkSettings, FileSystemSourceSettings, KafkaSource, KafkaSourceSettings, MappingJobSourceSettings}
 
 /**
  * Provide functions to find and resolve the environment variables used within FhirMappingJob definitions.
@@ -49,7 +49,8 @@ object EnvironmentVariableResolver {
   def resolveFhirMappingJob(job: FhirMappingJob): FhirMappingJob = {
     job.copy(
       sourceSettings = resolveSourceSettings(job.sourceSettings),
-      sinkSettings = resolveSinkSettings(job.sinkSettings)
+      sinkSettings = resolveSinkSettings(job.sinkSettings),
+      mappings = resolveMappings(job.mappings)
     )
   }
 
@@ -64,11 +65,32 @@ object EnvironmentVariableResolver {
       key -> (value match {
         case fs: FileSystemSourceSettings =>
           fs.copy(dataFolderPath = resolveEnvironmentVariables(fs.dataFolderPath))
+        case ks: KafkaSourceSettings if ks.asRedCap =>
+          ks.copy(sourceUri = resolveEnvironmentVariables(ks.sourceUri))
         case other => other // No changes for other types
       })
     }
   }
 
+  /**
+   * Resolves environment variables in mappings.
+   *
+   * @param mappings The list of mapping tasks
+   * @return The resolved mappings
+   */
+  private def resolveMappings(mappings: Seq[FhirMappingTask]): Seq[FhirMappingTask] = {
+    mappings.map { mapping =>
+      val updatedSourceBinding = mapping.sourceBinding.map { case (key, source) =>
+        key -> (source match {
+          case kafkaSource: KafkaSource =>
+            kafkaSource.copy(topicName = resolveEnvironmentVariables(kafkaSource.topicName))
+          case other => other // No changes for other source types
+        })
+      }
+
+      mapping.copy(sourceBinding = updatedSourceBinding)
+    }
+  }
 
   /**
    * Resolves environment variables in FhirRepositorySinkSettings.