diff --git a/src/jobs/da_job/mod.rs b/src/jobs/da_job/mod.rs
index 77b217ff..54b7856f 100644
--- a/src/jobs/da_job/mod.rs
+++ b/src/jobs/da_job/mod.rs
@@ -20,7 +20,7 @@ impl Job for DaJob {
             internal_id,
             job_type: JobType::DataSubmission,
             status: JobStatus::Created,
-            external_id: String::new(),
+            external_id: String::new().into(),
             metadata: HashMap::new(),
             version: 0,
         })
@@ -49,7 +49,7 @@ impl Job for DaJob {
     }
 
     async fn verify_job(&self, config: &Config, job: &JobItem) -> Result<JobVerificationStatus> {
-        Ok(config.da_client().verify_inclusion(job.external_id.as_str()).await?)
+        Ok(config.da_client().verify_inclusion(job.external_id.unwrap_string()?).await?)
     }
 
     fn max_process_attempts(&self) -> u64 {
diff --git a/src/jobs/types.rs b/src/jobs/types.rs
index f48b2372..b8950604 100644
--- a/src/jobs/types.rs
+++ b/src/jobs/types.rs
@@ -1,8 +1,69 @@
+use color_eyre::{eyre::eyre, Result};
 use mongodb::bson::serde_helpers::uuid_1_as_binary;
 use serde::{Deserialize, Serialize};
 use std::collections::HashMap;
 use uuid::Uuid;
 
+/// An external id.
+#[derive(Serialize, Deserialize, Debug, Clone)]
+#[serde(untagged)]
+pub enum ExternalId {
+    /// A string.
+    String(Box<str>),
+    /// A number.
+    Number(usize),
+}
+
+impl From<String> for ExternalId {
+    #[inline]
+    fn from(value: String) -> Self {
+        ExternalId::String(value.into_boxed_str())
+    }
+}
+
+impl From<usize> for ExternalId {
+    #[inline]
+    fn from(value: usize) -> Self {
+        ExternalId::Number(value)
+    }
+}
+
+impl ExternalId {
+    /// Unwraps the external id as a string.
+    ///
+    /// # Panics
+    ///
+    /// This function panics if the provided external id not a string.
+    #[track_caller]
+    #[inline]
+    pub fn unwrap_string(&self) -> Result<&str> {
+        match self {
+            ExternalId::String(s) => Ok(s),
+            _ => Err(unwrap_external_id_failed("string", self)),
+        }
+    }
+
+    /// Unwraps the external id as a number.
+    ///
+    /// # Panics
+    ///
+    /// This function panics if the provided external id is not a number.
+    #[track_caller]
+    #[inline]
+    #[allow(dead_code)] // temporarily unused (until the other pull request uses it)
+    pub fn unwrap_number(&self) -> Result<usize> {
+        match self {
+            ExternalId::Number(n) => Ok(*n),
+            _ => Err(unwrap_external_id_failed("number", self)),
+        }
+    }
+}
+
+/// Returns an error indicating that the provided external id coulnd't be unwrapped.
+fn unwrap_external_id_failed(expected: &str, got: &ExternalId) -> color_eyre::eyre::Error {
+    eyre!("wrong ExternalId type: expected {}, got {:?}", expected, got)
+}
+
 #[derive(Serialize, Deserialize, Debug, Clone)]
 pub enum JobType {
     /// Submitting DA data to the DA layer
@@ -46,7 +107,7 @@ pub struct JobItem {
     pub status: JobStatus,
     /// external id to track the status of the job. for ex, txn hash for blob inclusion
     /// or job_id from SHARP
-    pub external_id: String,
+    pub external_id: ExternalId,
     /// additional field to store values related to the job
     pub metadata: HashMap<String, String>,
     /// helps to keep track of the version of the item for optimistic locking