diff --git a/CHANGELOG.md b/CHANGELOG.md
index 74232e5d..7f9389b0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,6 +14,16 @@
 **Note**: Gaps between patch versions are faulty/broken releases.
 **Note**: A feature tagged as Experimental is in a high state of flux, you're at risk of it changing without notice.
 
+# 2.2.16
+
+Experimental modules require `fp-ts@^2.5.0`.
+
+- **Experimental**
+  - `Codec`
+    - add `readonly` combinator (@gcanti)
+  - `Encoder`
+    - add `readonly` combinator (@gcanti)
+
 # 2.2.15
 
 - **Experimental**
diff --git a/docs/modules/Codec.ts.md b/docs/modules/Codec.ts.md
index de0027cc..0f5feca2 100644
--- a/docs/modules/Codec.ts.md
+++ b/docs/modules/Codec.ts.md
@@ -35,6 +35,7 @@ Added in v2.2.3
   - [mapLeftWithInput](#mapleftwithinput)
   - [nullable](#nullable)
   - [partial](#partial)
+  - [readonly](#readonly)
   - [record](#record)
   - [refine](#refine)
   - [struct](#struct)
@@ -237,6 +238,16 @@ export declare function partial<P extends Record<string, Codec<unknown, any, any
 
 Added in v2.2.3
 
+## readonly
+
+**Signature**
+
+```ts
+export declare const readonly: <I, O, A>(codec: Codec<I, O, A>) => Codec<I, O, Readonly<A>>
+```
+
+Added in v2.2.16
+
 ## record
 
 **Signature**
diff --git a/docs/modules/Encoder.ts.md b/docs/modules/Encoder.ts.md
index 2d2cb614..153decb6 100644
--- a/docs/modules/Encoder.ts.md
+++ b/docs/modules/Encoder.ts.md
@@ -31,6 +31,7 @@ Added in v2.2.3
   - [lazy](#lazy)
   - [nullable](#nullable)
   - [partial](#partial)
+  - [readonly](#readonly)
   - [record](#record)
   - [struct](#struct)
   - [sum](#sum)
@@ -139,6 +140,16 @@ export declare function partial<P extends Record<string, Encoder<any, any>>>(
 
 Added in v2.2.3
 
+## readonly
+
+**Signature**
+
+```ts
+export declare const readonly: <O, A>(decoder: Encoder<O, A>) => Encoder<O, Readonly<A>>
+```
+
+Added in v2.2.16
+
 ## record
 
 **Signature**
diff --git a/package.json b/package.json
index f904dc85..9c7cc243 100644
--- a/package.json
+++ b/package.json
@@ -1,13 +1,13 @@
 {
   "name": "io-ts",
-  "version": "2.2.15",
+  "version": "2.2.16",
   "description": "TypeScript runtime type system for IO decoding/encoding",
   "main": "lib/index.js",
   "module": "es6/index.js",
   "typings": "lib/index.d.ts",
   "sideEffects": false,
   "scripts": {
-    "lint": "tslint -p tsconfig.tslint.json src/**/*.ts test/**/*.ts",
+    "lint": "tslint -p .",
     "eslint": "eslint \"src/**/*.ts\" \"test/**/*.ts\" \"scripts/**/*.ts\"",
     "jest": "jest",
     "prettier": "prettier --no-semi --single-quote --print-width 120 --parser typescript --list-different \"{src,test}/**/*.ts\"",
diff --git a/src/Codec.ts b/src/Codec.ts
index 035665ff..fe43c2aa 100644
--- a/src/Codec.ts
+++ b/src/Codec.ts
@@ -304,6 +304,12 @@ export function lazy<I, O, A>(id: string, f: () => Codec<I, O, A>): Codec<I, O,
   return make(D.lazy(id, f), E.lazy(f))
 }
 
+/**
+ * @category combinators
+ * @since 2.2.16
+ */
+export const readonly: <I, O, A>(codec: Codec<I, O, A>) => Codec<I, O, Readonly<A>> = identity
+
 /**
  * @category combinators
  * @since 2.2.8
diff --git a/src/Encoder.ts b/src/Encoder.ts
index 5b7eac91..8cf7a085 100644
--- a/src/Encoder.ts
+++ b/src/Encoder.ts
@@ -162,6 +162,12 @@ export function lazy<O, A>(f: () => Encoder<O, A>): Encoder<O, A> {
   }
 }
 
+/**
+ * @category combinators
+ * @since 2.2.16
+ */
+export const readonly: <O, A>(decoder: Encoder<O, A>) => Encoder<O, Readonly<A>> = identity
+
 // -------------------------------------------------------------------------------------
 // non-pipeables
 // -------------------------------------------------------------------------------------