diff --git a/README.md b/README.md
index 78e78c9..4d27f2b 100644
--- a/README.md
+++ b/README.md
@@ -175,6 +175,6 @@ const TNumberBiggerThan10 = TValidate(
 All guards can be imported as a single module, which enables tree-shaking:
 
 ```ts
-import TString from "tguard/guards/TString";
-import { GuardedType } from "tguard/Guard";
+import TString from "tguard/lib/guards/TString";
+import Guard, { GuardedType } from "tguard/lib/Guard";
 ```
diff --git a/docs/README.md b/docs/README.md
index ec55f6e..417ed4f 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -177,6 +177,6 @@ const TNumberBiggerThan10 = TValidate(
 All guards can be imported as a single module, which enables tree-shaking:
 
 ```ts
-import TString from "tguard/guards/TString";
-import { GuardedType } from "tguard/Guard";
+import TString from "tguard/lib/guards/TString";
+import Guard, { GuardedType } from "tguard/lib/Guard";
 ```
diff --git a/docs/classes/Guard.md b/docs/classes/Guard.md
index 055e788..bb05f47 100644
--- a/docs/classes/Guard.md
+++ b/docs/classes/Guard.md
@@ -47,7 +47,7 @@ An abstract class, which is the parent class of all Guards. (Names starting with
 
 #### Defined in
 
-[src/Guard.ts:11](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/Guard.ts#L11)
+[src/Guard.ts:11](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/Guard.ts#L11)
 
 ## Methods
 
@@ -67,7 +67,7 @@ An abstract class, which is the parent class of all Guards. (Names starting with
 
 #### Defined in
 
-[src/Guard.ts:13](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/Guard.ts#L13)
+[src/Guard.ts:13](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/Guard.ts#L13)
 
 ___
 
@@ -87,4 +87,4 @@ value is T
 
 #### Defined in
 
-[src/Guard.ts:12](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/Guard.ts#L12)
+[src/Guard.ts:12](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/Guard.ts#L12)
diff --git a/docs/classes/ValidationError.md b/docs/classes/ValidationError.md
index f0e6ad0..699e480 100644
--- a/docs/classes/ValidationError.md
+++ b/docs/classes/ValidationError.md
@@ -48,7 +48,7 @@ Error.constructor
 
 #### Defined in
 
-[src/errors.ts:5](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/errors.ts#L5)
+[src/errors.ts:5](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/errors.ts#L5)
 
 ## Properties
 
@@ -58,7 +58,7 @@ Error.constructor
 
 #### Defined in
 
-[src/errors.ts:3](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/errors.ts#L3)
+[src/errors.ts:3](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/errors.ts#L3)
 
 ___
 
@@ -96,7 +96,7 @@ ___
 
 #### Defined in
 
-[src/errors.ts:2](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/errors.ts#L2)
+[src/errors.ts:2](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/errors.ts#L2)
 
 ___
 
diff --git a/docs/modules.md b/docs/modules.md
index 275d174..df7c27e 100644
--- a/docs/modules.md
+++ b/docs/modules.md
@@ -29,6 +29,7 @@
 - [TString](modules.md#tstring)
 - [TStringEmail](modules.md#tstringemail)
 - [TStringISODate](modules.md#tstringisodate)
+- [TStringJSON](modules.md#tstringjson)
 - [TStringJWT](modules.md#tstringjwt)
 - [TStringMIMEType](modules.md#tstringmimetype)
 - [TStringPhoneNumber](modules.md#tstringphonenumber)
@@ -67,7 +68,7 @@ Infers the type, that the given `Guard` guards.
 
 #### Defined in
 
-[src/Guard.ts:22](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/Guard.ts#L22)
+[src/Guard.ts:22](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/Guard.ts#L22)
 
 ___
 
@@ -85,7 +86,7 @@ Infers the type, that the given `Schema` represents.
 
 #### Defined in
 
-[src/guards/TObject/types.ts:8](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TObject/types.ts#L8)
+[src/guards/TObject/types.ts:8](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TObject/types.ts#L8)
 
 ## Variables
 
@@ -99,7 +100,7 @@ Guard that accepts any value.
 
 #### Defined in
 
-[src/guards/TAny/index.ts:8](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TAny/index.ts#L8)
+[src/guards/TAny/index.ts:8](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TAny/index.ts#L8)
 
 ___
 
@@ -114,7 +115,7 @@ Does not accept null.
 
 #### Defined in
 
-[src/guards/TAnyObject/index.ts:9](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TAnyObject/index.ts#L9)
+[src/guards/TAnyObject/index.ts:9](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TAnyObject/index.ts#L9)
 
 ___
 
@@ -128,7 +129,7 @@ Primitive guard that only accepts `bigint` values.
 
 #### Defined in
 
-[src/guards/TBigInt/index.ts:8](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TBigInt/index.ts#L8)
+[src/guards/TBigInt/index.ts:8](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TBigInt/index.ts#L8)
 
 ___
 
@@ -142,7 +143,7 @@ Primitive guard that only accepts `boolean` values.
 
 #### Defined in
 
-[src/guards/TBoolean/index.ts:8](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TBoolean/index.ts#L8)
+[src/guards/TBoolean/index.ts:8](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TBoolean/index.ts#L8)
 
 ___
 
@@ -156,7 +157,7 @@ Primitive guard that only accepts `function` values.
 
 #### Defined in
 
-[src/guards/TFunction/index.ts:8](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TFunction/index.ts#L8)
+[src/guards/TFunction/index.ts:8](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TFunction/index.ts#L8)
 
 ___
 
@@ -177,7 +178,7 @@ TInteger.isValid(15); // true
 
 #### Defined in
 
-[src/guards/TInteger/index.ts:15](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TInteger/index.ts#L15)
+[src/guards/TInteger/index.ts:15](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TInteger/index.ts#L15)
 
 ___
 
@@ -198,7 +199,7 @@ TIntegerAsString.isValid("15"); // true
 
 #### Defined in
 
-[src/guards/TIntegerAsString/index.ts:16](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TIntegerAsString/index.ts#L16)
+[src/guards/TIntegerAsString/index.ts:16](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TIntegerAsString/index.ts#L16)
 
 ___
 
@@ -212,7 +213,7 @@ Guard that only accepts `null`.
 
 #### Defined in
 
-[src/guards/TNull/index.ts:8](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TNull/index.ts#L8)
+[src/guards/TNull/index.ts:8](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TNull/index.ts#L8)
 
 ___
 
@@ -227,7 +228,7 @@ Not accepts `NaN`.
 
 #### Defined in
 
-[src/guards/TNumber/index.ts:9](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TNumber/index.ts#L9)
+[src/guards/TNumber/index.ts:9](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TNumber/index.ts#L9)
 
 ___
 
@@ -248,7 +249,7 @@ TNumberAsString.isValid("15.223"); // true
 
 #### Defined in
 
-[src/guards/TNumberAsString/index.ts:15](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TNumberAsString/index.ts#L15)
+[src/guards/TNumberAsString/index.ts:15](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TNumberAsString/index.ts#L15)
 
 ___
 
@@ -262,7 +263,7 @@ Primitive guard that only accepts `string` values.
 
 #### Defined in
 
-[src/guards/TString/index.ts:8](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TString/index.ts#L8)
+[src/guards/TString/index.ts:8](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TString/index.ts#L8)
 
 ___
 
@@ -283,7 +284,7 @@ TStringEmail.name === "string(email)"; // true
 
 #### Defined in
 
-[src/guards/TStringEmail/index.ts:16](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TStringEmail/index.ts#L16)
+[src/guards/TStringEmail/index.ts:16](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TStringEmail/index.ts#L16)
 
 ___
 
@@ -304,7 +305,28 @@ TStringISODate.name === "string(date)"; // true
 
 #### Defined in
 
-[src/guards/TStringISODate/index.ts:16](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TStringISODate/index.ts#L16)
+[src/guards/TStringISODate/index.ts:16](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TStringISODate/index.ts#L16)
+
+___
+
+### TStringJSON
+
+• `Const` **TStringJSON**: [`Guard`](classes/Guard.md)<`string`\>
+
+A `Guard` which validates if a string is a valid JSON.
+
+`guard.name: "string(JSON)"`
+
+**`example`**
+```ts
+TStringJSON.isValid("1234"); // false
+TStringJSON.isValid("{\"foo\": 2}"); // true
+TStringJSON.name === "string(JSON)"; // true
+```
+
+#### Defined in
+
+[src/guards/TStringJSON/index.ts:16](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TStringJSON/index.ts#L16)
 
 ___
 
@@ -325,7 +347,7 @@ TStringJWT.name === "string(JSON)"; // true
 
 #### Defined in
 
-[src/guards/TStringJWT/index.ts:16](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TStringJWT/index.ts#L16)
+[src/guards/TStringJWT/index.ts:16](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TStringJWT/index.ts#L16)
 
 ___
 
@@ -346,7 +368,7 @@ TStringMIMEType.name === "string(MIME type)"; // true
 
 #### Defined in
 
-[src/guards/TStringMIMEType/index.ts:16](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TStringMIMEType/index.ts#L16)
+[src/guards/TStringMIMEType/index.ts:16](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TStringMIMEType/index.ts#L16)
 
 ___
 
@@ -368,7 +390,7 @@ TStringPhoneNumber.name === "string(phone number)"; // true
 
 #### Defined in
 
-[src/guards/TStringPhoneNumber/index.ts:17](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TStringPhoneNumber/index.ts#L17)
+[src/guards/TStringPhoneNumber/index.ts:17](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TStringPhoneNumber/index.ts#L17)
 
 ___
 
@@ -389,7 +411,7 @@ TStringSemVer.name === "string(SemVer)"; // true
 
 #### Defined in
 
-[src/guards/TStringSemVer/index.ts:16](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TStringSemVer/index.ts#L16)
+[src/guards/TStringSemVer/index.ts:16](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TStringSemVer/index.ts#L16)
 
 ___
 
@@ -410,7 +432,7 @@ TStringURL.name === "string(URL)"; // true
 
 #### Defined in
 
-[src/guards/TStringURL/index.ts:16](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TStringURL/index.ts#L16)
+[src/guards/TStringURL/index.ts:16](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TStringURL/index.ts#L16)
 
 ___
 
@@ -434,7 +456,7 @@ TStringUUID.name === "string(UUID)"; // true
 
 #### Defined in
 
-[src/guards/TStringUUID/index.ts:19](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TStringUUID/index.ts#L19)
+[src/guards/TStringUUID/index.ts:19](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TStringUUID/index.ts#L19)
 
 ___
 
@@ -448,7 +470,7 @@ Primitive guard that only accepts `undefined` values.
 
 #### Defined in
 
-[src/guards/TUndefined/index.ts:8](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TUndefined/index.ts#L8)
+[src/guards/TUndefined/index.ts:8](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TUndefined/index.ts#L8)
 
 ## Functions
 
@@ -483,7 +505,7 @@ Accepts a value when it was accepted by both `guardA` and `guardB`.
 
 #### Defined in
 
-[src/guards/TAnd/index.ts:14](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TAnd/index.ts#L14)
+[src/guards/TAnd/index.ts:14](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TAnd/index.ts#L14)
 
 ___
 
@@ -526,7 +548,7 @@ A `Guard` that checks if the given value is an array of the given type.
 
 #### Defined in
 
-[src/guards/TArray/index.ts:24](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TArray/index.ts#L24)
+[src/guards/TArray/index.ts:24](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TArray/index.ts#L24)
 
 ___
 
@@ -569,7 +591,7 @@ A `Guard` which checks if the given value is equals to the `constant` literal.
 
 #### Defined in
 
-[src/guards/TConstant/index.ts:26](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TConstant/index.ts#L26)
+[src/guards/TConstant/index.ts:26](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TConstant/index.ts#L26)
 
 ___
 
@@ -608,7 +630,7 @@ A `Guard` that accepts a value when it was **not** accepted by the given guard.
 
 #### Defined in
 
-[src/guards/TNot/index.ts:21](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TNot/index.ts#L21)
+[src/guards/TNot/index.ts:21](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TNot/index.ts#L21)
 
 ___
 
@@ -656,7 +678,7 @@ A `Guard`.
 
 #### Defined in
 
-[src/guards/TObject/index.ts:30](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TObject/index.ts#L30)
+[src/guards/TObject/index.ts:30](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TObject/index.ts#L30)
 
 ___
 
@@ -714,7 +736,7 @@ Similar in concept as TypeScript's `{[keys: string]: number}` type annotations.
 
 #### Defined in
 
-[src/guards/TObjectOfShape/index.ts:39](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TObjectOfShape/index.ts#L39)
+[src/guards/TObjectOfShape/index.ts:39](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TObjectOfShape/index.ts#L39)
 
 ___
 
@@ -760,7 +782,7 @@ Accepts a value when it was accepted by at least one of the `guards`.
 
 #### Defined in
 
-[src/guards/TOr/index.ts:22](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TOr/index.ts#L22)
+[src/guards/TOr/index.ts:22](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TOr/index.ts#L22)
 
 ___
 
@@ -794,7 +816,7 @@ A `Guard` that accepts only strings that are base64 encoded.
 
 #### Defined in
 
-[src/guards/TStringBase64/index.ts:21](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TStringBase64/index.ts#L21)
+[src/guards/TStringBase64/index.ts:21](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TStringBase64/index.ts#L21)
 
 ___
 
@@ -829,7 +851,7 @@ A `Guard` that accepts only strings that matches the given `regexp`.
 
 #### Defined in
 
-[src/guards/TStringMatch/index.ts:23](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TStringMatch/index.ts#L23)
+[src/guards/TStringMatch/index.ts:23](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TStringMatch/index.ts#L23)
 
 ___
 
@@ -864,7 +886,7 @@ A `Guard` that accepts only strings, that is in the given length range.
 
 #### Defined in
 
-[src/guards/TStringWithLength/index.ts:22](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TStringWithLength/index.ts#L22)
+[src/guards/TStringWithLength/index.ts:22](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TStringWithLength/index.ts#L22)
 
 ___
 
@@ -902,4 +924,4 @@ const TBiggerThan10 = TValidate<number>(
 
 #### Defined in
 
-[src/guards/TValidate/index.ts:22](https://github.com/davidkarolyi/tguard/blob/d0ca035/src/guards/TValidate/index.ts#L22)
+[src/guards/TValidate/index.ts:22](https://github.com/davidkarolyi/tguard/blob/0dd2269/src/guards/TValidate/index.ts#L22)