diff --git a/src/main/java/uk/ac/ebi/tsc/tesk/k8s/constant/Constants.java b/src/main/java/uk/ac/ebi/tsc/tesk/k8s/constant/Constants.java
index f6b7716..ede544b 100644
--- a/src/main/java/uk/ac/ebi/tsc/tesk/k8s/constant/Constants.java
+++ b/src/main/java/uk/ac/ebi/tsc/tesk/k8s/constant/Constants.java
@@ -21,11 +21,16 @@ public class Constants {
      */
     public static final String TASKMASTER_INPUT = "JSON_INPUT";
 
+    /**
+     * ENV var that stores the callback URL
+     */
+    public static final String TASKMASTER_CALLBACK_URL = "CALLBACK_URL";
+
     /**
      * Key in JSON taskmaster input, which holds list of executors
      */
     public static final String TASKMASTER_INPUT_EXEC_KEY = "executors";
-
+    
     /**
      *
      */
diff --git a/src/main/java/uk/ac/ebi/tsc/tesk/k8s/convert/TesKubernetesConverter.java b/src/main/java/uk/ac/ebi/tsc/tesk/k8s/convert/TesKubernetesConverter.java
index 2c575a6..e12e2e4 100644
--- a/src/main/java/uk/ac/ebi/tsc/tesk/k8s/convert/TesKubernetesConverter.java
+++ b/src/main/java/uk/ac/ebi/tsc/tesk/k8s/convert/TesKubernetesConverter.java
@@ -113,6 +113,10 @@ public V1Job fromTesTaskToK8sJob(TesTask task, User user) {
         String taskMasterInputAsJSON = this.gson.toJson(taskMasterInput);
         //placing taskmaster's parameter (JSONed map of: inputs, outputs, volumes, executors (as jobs) into ENV variable in taskmaster spec
         taskMasterJob.getSpec().getTemplate().getSpec().getContainers().get(0).getEnv().stream().filter(x -> x.getName().equals(TASKMASTER_INPUT)).forEach(x -> x.setValue(taskMasterInputAsJSON));
+        //place callback URL as ENV variable in taskmaster spec
+        if (task.getCallbackUrl() != null) {
+            taskMasterJob.getSpec().getTemplate().getSpec().getContainers().get(0).addEnvItem(new V1EnvVar().name(TASKMASTER_CALLBACK_URL).value(task.getCallbackUrl()));
+        }
         return taskMasterJob;
     }
 
diff --git a/src/main/java/uk/ac/ebi/tsc/tesk/tes/model/TesTask.java b/src/main/java/uk/ac/ebi/tsc/tesk/tes/model/TesTask.java
index 1720b13..2b7901c 100644
--- a/src/main/java/uk/ac/ebi/tsc/tesk/tes/model/TesTask.java
+++ b/src/main/java/uk/ac/ebi/tsc/tesk/tes/model/TesTask.java
@@ -32,6 +32,9 @@ public class TesTask   {
   @JsonProperty("description")
   private String description;
 
+  @JsonProperty("callback_url")
+  private String callbackUrl;
+
   @JsonProperty("inputs")
   @Valid
   private List<TesInput> inputs = null;
@@ -144,6 +147,26 @@ public void setDescription(String description) {
     this.description = description;
   }
 
+  public TesTask callbackUrl(String callbackUrl) {
+    this.callbackUrl = callbackUrl;
+    return this;
+  }
+
+  /**
+   * Optional user-provided callback URL.
+   * @return callbackUrl
+   */
+  @ApiModelProperty(value = "Optional user-provided callback URL.")
+
+
+  public String getCallbackUrl() {
+    return callbackUrl;
+  }
+
+  public void setCallbackUrl(String callbackUrl) {
+    this.callbackUrl = callbackUrl;
+  }
+
   public TesTask inputs(List<TesInput> inputs) {
     this.inputs = inputs;
     return this;
@@ -372,6 +395,7 @@ public boolean equals(Object o) {
         Objects.equals(this.state, tesTask.state) &&
         Objects.equals(this.name, tesTask.name) &&
         Objects.equals(this.description, tesTask.description) &&
+        Objects.equals(this.callbackUrl, tesTask.callbackUrl) &&
         Objects.equals(this.inputs, tesTask.inputs) &&
         Objects.equals(this.outputs, tesTask.outputs) &&
         Objects.equals(this.resources, tesTask.resources) &&
@@ -384,7 +408,7 @@ public boolean equals(Object o) {
 
   @Override
   public int hashCode() {
-    return Objects.hash(id, state, name, description, inputs, outputs, resources, executors, volumes, tags, logs, creationTime);
+    return Objects.hash(id, state, name, description, callbackUrl, inputs, outputs, resources, executors, volumes, tags, logs, creationTime);
   }
 
   @Override
@@ -396,6 +420,7 @@ public String toString() {
     sb.append("    state: ").append(toIndentedString(state)).append("\n");
     sb.append("    name: ").append(toIndentedString(name)).append("\n");
     sb.append("    description: ").append(toIndentedString(description)).append("\n");
+    sb.append("    callbackUrl: ").append(toIndentedString(callbackUrl)).append("\n");
     sb.append("    inputs: ").append(toIndentedString(inputs)).append("\n");
     sb.append("    outputs: ").append(toIndentedString(outputs)).append("\n");
     sb.append("    resources: ").append(toIndentedString(resources)).append("\n");