diff --git a/packages/backends/backend-test/src/createNewJob.ts b/packages/backends/backend-test/src/createNewJob.ts
index 2885bc1..73ba7f3 100644
--- a/packages/backends/backend-test/src/createNewJob.ts
+++ b/packages/backends/backend-test/src/createNewJob.ts
@@ -1,4 +1,5 @@
 import { NewJobData } from "@sidequest/backend";
+import { DuplicatedJobError } from "@sidequest/core";
 import { describe, it } from "vitest";
 import { backend } from "./backend";
 
@@ -124,7 +125,7 @@ export default function defineCreateNewJobTestSuite() {
       };
 
       await backend.createNewJob(job);
-      await expect(backend.createNewJob(job2)).rejects.toThrow();
+      await expect(backend.createNewJob(job2)).rejects.toThrow(DuplicatedJobError);
     });
   });
 }
diff --git a/packages/backends/mongo/src/mongo-backend.ts b/packages/backends/mongo/src/mongo-backend.ts
index c69552d..57316da 100644
--- a/packages/backends/mongo/src/mongo-backend.ts
+++ b/packages/backends/mongo/src/mongo-backend.ts
@@ -10,7 +10,7 @@ import {
   UpdateJobData,
   UpdateQueueData,
 } from "@sidequest/backend";
-import { JobData, JobState, QueueConfig } from "@sidequest/core";
+import { DuplicatedJobError, JobData, JobState, QueueConfig } from "@sidequest/core";
 import { Collection, Db, Filter, MongoClient } from "mongodb";
 import { addCoalescedField, generateTimeBuckets, getTimeRangeConfig, matchDateRange, parseTimeRange } from "./utils";
 
@@ -156,7 +156,20 @@ export default class MongoBackend implements Backend {
       inserted_at: now,
       available_at: job.available_at ?? now,
     };
-    await this.jobs.insertOne(doc);
+    try {
+      await this.jobs.insertOne(doc);
+    } catch (error) {
+      if (
+        error instanceof Error &&
+        (("code" in error && error.code === 11000) ||
+          error.message?.includes("E11000") ||
+          error.message?.includes("unique_digest"))
+      ) {
+        throw new DuplicatedJobError(doc);
+      }
+
+      throw error;
+    }
     return doc;
   }
 
diff --git a/packages/backends/mysql/src/mysql-backend.ts b/packages/backends/mysql/src/mysql-backend.ts
index e6e7dc5..f26242e 100644
--- a/packages/backends/mysql/src/mysql-backend.ts
+++ b/packages/backends/mysql/src/mysql-backend.ts
@@ -25,6 +25,31 @@ const defaultKnexConfig = {
   },
 };
 
+const MYSQL_ER_DUP_ENTRY = 1062;
+
+function isUniqueDigestDuplicateError(error: unknown): boolean {
+  if (!(error instanceof Error)) {
+    return false;
+  }
+
+  const code = "code" in error ? error.code : undefined;
+  const errno = "errno" in error ? error.errno : undefined;
+  const sqlMessage = "sqlMessage" in error && typeof error.sqlMessage === "string" ? error.sqlMessage : "";
+  const constraint = "constraint" in error && typeof error.constraint === "string" ? error.constraint : "";
+  const details = `${error.message}\n${sqlMessage}\n${constraint}`;
+
+  if (!details.includes("unique_digest")) {
+    return false;
+  }
+
+  return (
+    code === "ER_DUP_ENTRY" ||
+    errno === MYSQL_ER_DUP_ENTRY ||
+    constraint === "sidequest_jobs_unique_digest_active_idx" ||
+    /duplicate entry/i.test(details)
+  );
+}
+
 export default class MysqlBackend extends SQLBackend {
   constructor(dbConfig: string | SQLDriverConfig) {
     const knexConfig: Knex.Config = {
@@ -119,11 +144,7 @@ export default class MysqlBackend extends SQLBackend {
 
       return insertedJob;
     } catch (error) {
-      if (
-        error instanceof Error &&
-        (error.message?.includes("sidequest_jobs.unique_digest") ||
-          ("constraint" in error && error.constraint === "sidequest_jobs_unique_digest_active_idx"))
-      ) {
+      if (isUniqueDigestDuplicateError(error)) {
         throw new DuplicatedJobError(job as JobData);
       }