diff --git a/backend/doc/domain/resource_lookup.py b/backend/doc/domain/resource_lookup.py
index 616f0d31..4a33ef6b 100644
--- a/backend/doc/domain/resource_lookup.py
+++ b/backend/doc/domain/resource_lookup.py
@@ -723,7 +723,8 @@ def add_data_not_supplied_by_data_api(repos_info: list[RepoEntry]) -> list[RepoE
     """
     DOC needs to support some resources which are not supplied by the
     data API so we augment the data returned from the data API to include
-    them here.
+    them here. If a (language code, resource type) pair already exists in
+    repos_info, do not add it again.
     """
 
     def make_entry(url: HttpUrl, resource_type: str, lang: Language) -> RepoEntry:
@@ -774,7 +775,15 @@ def make_entry(url: HttpUrl, resource_type: str, lang: Language) -> RepoEntry:
             en_lang,
         ),
     ]
-    repos_info.extend(extra_entries)
+    existing_pairs = {
+        (entry.content.language.ietf_code, entry.content.resource_type)
+        for entry in repos_info
+    }
+    for entry in extra_entries:
+        key = (entry.content.language.ietf_code, entry.content.resource_type)
+        if key not in existing_pairs:
+            repos_info.append(entry)
+            existing_pairs.add(key)
     return repos_info
 
 
diff --git a/frontend/tests/e2e/test.ts b/frontend/tests/e2e/test.ts
index 3691a8d3..3a515d9e 100644
--- a/frontend/tests/e2e/test.ts
+++ b/frontend/tests/e2e/test.ts
@@ -420,3 +420,14 @@ test('test burmese', async ({ page }) => {
   await page.getByText('Use PrinceXml to produce the').click()
   await page.getByRole('button', { name: 'Generate File' }).click()
 })
+
+test('test merge of data API data and DOC only data', async ({ page }) => {
+  await page.goto('http://localhost:8001/')
+  await expect(page.getByRole('main')).toContainText('Bahasa Indonesia (Indonesian)')
+  await page.getByLabel('Bahasa Indonesia (Indonesian').check()
+  await page.getByRole('button', { name: 'Next' }).click()
+  await page.getByText('Matius').click()
+  await page.getByRole('button', { name: 'Next' }).click()
+  await expect(page.locator('body')).toContainText('Bahasa Indonesian Bible')
+  await expect(page.locator('body')).toContainText('Translation Notes')
+})