diff --git a/docs/modules/README.md b/docs/modules/README.md
index 5c8dda3..006a8f7 100644
--- a/docs/modules/README.md
+++ b/docs/modules/README.md
@@ -12,6 +12,7 @@ ESLint plugin.
 
 ## List of modules
 
+- [`@75lb/deep-merge`](./deep-merge.md)
 - [`@jsdevtools/ezspawn`](./ez-spawn.md)
 - [`axios`](./fetch.md)
 - [`bluebird`](./bluebird-q.md)
diff --git a/docs/modules/deep-merge.md b/docs/modules/deep-merge.md
new file mode 100644
index 0000000..9b62396
--- /dev/null
+++ b/docs/modules/deep-merge.md
@@ -0,0 +1,27 @@
+---
+description: Modern alternatives to packages for deep merging objects
+---
+
+# Replacements for deep merge packages
+
+## `defu`
+
+If you need to deep merge two objects, you can use [`defu`](https://github.com/unjs/defu):
+
+```ts
+import { defu } from 'defu'
+
+const options = defu(object, defaults)
+```
+
+## `@fastify/deepmerge`
+
+The [`@fastify/deepmerge`](https://github.com/fastify/deepmerge) package is another fast and small alternative.
+
+It also offers more options for customizing the merge behavior than other libraries.
+
+```ts
+import deepMerge from '@fastify/deepmerge'
+
+const options = deepMerge(object, defaults)
+```
diff --git a/manifests/preferred.json b/manifests/preferred.json
index c06ac71..66c1a3f 100644
--- a/manifests/preferred.json
+++ b/manifests/preferred.json
@@ -1,5 +1,11 @@
 {
   "mappings": {
+    "@75lb/deep-merge": {
+      "type": "module",
+      "moduleName": "@75lb/deep-merge",
+      "replacements": ["defu", "@fastify/deepmerge"],
+      "url": {"type": "e18e", "id": "deep-merge"}
+    },
     "@iarna/toml": {
       "type": "module",
       "moduleName": "@iarna/toml",
@@ -2739,6 +2745,12 @@
       "url": {"type": "e18e", "id": "faker"},
       "replacementModule": "@faker-js/faker"
     },
+    "@fastify/deepmerge": {
+      "id": "@fastify/deepmerge",
+      "type": "documented",
+      "url": {"type": "e18e", "id": "deep-merge"},
+      "replacementModule": "@fastify/deepmerge"
+    },
     "@material/web": {
       "id": "@material/web",
       "type": "documented",
@@ -2967,7 +2979,7 @@
     "defu": {
       "id": "defu",
       "type": "documented",
-      "url": {"type": "e18e", "id": "extend"},
+      "url": {"type": "e18e", "id": "deep-merge"},
       "replacementModule": "defu"
     },
     "dequal": {