diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8fe40b8b..c3e7d959 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,11 +1,8 @@
-
-
 # [0.6.0](https://github.com/KATT/tupleson/compare/0.5.0...0.6.0) (2023-09-30)
 
-
 ### Features
 
-* add custom serializer example ([#8](https://github.com/KATT/tupleson/issues/8)) ([58eab05](https://github.com/KATT/tupleson/commit/58eab05baff0dd07803b5aa01c402fcd02df5b09))
+- add custom serializer example ([#8](https://github.com/KATT/tupleson/issues/8)) ([58eab05](https://github.com/KATT/tupleson/commit/58eab05baff0dd07803b5aa01c402fcd02df5b09))
 
 # [0.5.0](https://github.com/KATT/tupleson/compare/0.4.0...0.5.0) (2023-09-30)
 
@@ -42,4 +39,4 @@
 ### Features
 
 - initial version ([#1](https://github.com/KATT/tupleson/issues/1)) ([ccce25b](https://github.com/KATT/tupleson/commit/ccce25b6a039cf2e5c1a774c1ab022f0946ca8d5))
-- initialized repo ✨ ([c9e92a4](https://github.com/KATT/tupleson/commit/c9e92a42c97a8bc1ee3a9214f65626425c8598e3))
\ No newline at end of file
+- initialized repo ✨ ([c9e92a4](https://github.com/KATT/tupleson/commit/c9e92a42c97a8bc1ee3a9214f65626425c8598e3))
diff --git a/README.md b/README.md
index b4b13d08..a57fa5c4 100644
--- a/README.md
+++ b/README.md
@@ -106,7 +106,7 @@ type Obj = typeof obj;
 
 ### Extend with a custom serializer
 
-#### `Temporal`
+#### [Temporal](https://www.npmjs.com/package/@js-temporal/polyfill)
 
 > See test reference in [`./src/extend/temporal.test.ts`](./src/extend/temporal.test.ts)
 
@@ -118,14 +118,14 @@ import { TsonType, createTson } from "tupleson";
 const plainDate: TsonType<Temporal.PlainDate, string> = {
 	deserialize: (v) => Temporal.PlainDate.from(v),
 	key: "PlainDate",
-	serialize: (v) => v.toString(),
+	serialize: (v) => v.toJSON(),
 	test: (v) => v instanceof Temporal.PlainDate,
 };
 
 const instant: TsonType<Temporal.Instant, string> = {
 	deserialize: (v) => Temporal.Instant.from(v),
 	key: "Instant",
-	serialize: (v) => v.toString(),
+	serialize: (v) => v.toJSON(),
 	test: (v) => v instanceof Temporal.Instant,
 };
 
@@ -134,7 +134,25 @@ const tson = createTson({
 });
 ```
 
-**Footnotes**:
+#### [Decimal.js](https://github.com/MikeMcl/decimal.js)
+
+> See test reference in [`./src/extend/decimal.test.ts`](./src/extend/decimal.test.ts)
+
+```ts
+/* eslint-disable eslint-comments/disable-enable-pair, @typescript-eslint/no-unused-vars, n/no-missing-import, n/no-unpublished-import */
+import { Decimal } from "decimal.js";
+
+const decimalJs: TsonType<Decimal, string> = {
+	deserialize: (v) => new Decimal(v),
+	key: "Decimal",
+	serialize: (v) => v.toJSON(),
+	test: (v) => v instanceof Decimal,
+};
+
+const tson = createTson({
+	types: [decimalJs],
+});
+```
 
 [^1]: We don't support circular references as we don't think it's very desireable, but if you wanna contribute with adding opt-in support for that, you are very welcome!
 
diff --git a/package.json b/package.json
index cbddae9a..86a99786 100644
--- a/package.json
+++ b/package.json
@@ -31,6 +31,7 @@
 		"test": "vitest",
 		"tsc": "tsc"
 	},
+	"dependencies": {},
 	"devDependencies": {
 		"@js-temporal/polyfill": "^0.4.4",
 		"@release-it/conventional-changelog": "^7.0.2",
@@ -41,6 +42,7 @@
 		"@vitest/coverage-v8": "^0.34.6",
 		"console-fail-test": "^0.2.3",
 		"cspell": "^7.3.7",
+		"decimal.js": "^10.4.3",
 		"eslint": "^8.50.0",
 		"eslint-plugin-deprecation": "^2.0.0",
 		"eslint-plugin-eslint-comments": "^3.2.0",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index bc24daaa..9553f4b6 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -32,6 +32,9 @@ devDependencies:
   cspell:
     specifier: ^7.3.7
     version: 7.3.7
+  decimal.js:
+    specifier: ^10.4.3
+    version: 10.4.3
   eslint:
     specifier: ^8.50.0
     version: 8.50.0
@@ -2376,6 +2379,10 @@ packages:
     engines: {node: '>=0.10.0'}
     dev: true
 
+  /decimal.js@10.4.3:
+    resolution: {integrity: sha512-VBBaLc1MgL5XpzgIP7ny5Z6Nx3UrRkIViUkPUdtl9aya5amy3De1gsUUSB1g3+3sExYNjCAsAznmukyxCb1GRA==}
+    dev: true
+
   /decompress-response@6.0.0:
     resolution: {integrity: sha512-aW35yZM6Bb/4oJlZncMH2LCoZtJXTRxES17vE3hoRiowU2kWHaJKFkSBDnDR+cm9J+9QhXmREyIfv0pji9ejCQ==}
     engines: {node: '>=10'}
diff --git a/src/extend/decimal.test.ts b/src/extend/decimal.test.ts
new file mode 100644
index 00000000..c0c34eb2
--- /dev/null
+++ b/src/extend/decimal.test.ts
@@ -0,0 +1,35 @@
+import { Decimal } from "decimal.js";
+import { expect, test } from "vitest";
+
+import { TsonType, createTson } from "../index.js";
+
+const decimalJs: TsonType<Decimal, string> = {
+	deserialize: (v) => new Decimal(v),
+	key: "Decimal",
+	serialize: (v) => v.toJSON(),
+	test: (v) => v instanceof Decimal,
+};
+
+const tson = createTson({
+	types: [decimalJs],
+});
+
+test("Decimal.js", () => {
+	const expected = new Decimal(1.23);
+	const serialized = tson.serialize(expected);
+
+	expect(serialized).toMatchInlineSnapshot(`
+		{
+		  "json": [
+		    "Decimal",
+		    "1.23",
+		    "__tson",
+		  ],
+		  "nonce": "__tson",
+		}
+	`);
+
+	const deserialized = tson.deserialize(serialized);
+
+	expect(deserialized).toEqual(expected);
+});