Platformsios 8.0, requires ARC




SchemaValidator is available through CocoaPods. To install
it, simply add the following line to your Podfile:

pod "SchemaValidator"


You can use SchemaValidator to validate JSON like dictionary objects (for eg: anything that conforms to [NSObject:AnyObject] in Swift.

To define a Schema do:

let schema:Schema = [
    "timestamp": [V.Present, V.Integer],
    "sourceId" : [V.Present],
    "userInfo" : [
        "email" : [V.Email],
        "age"   : [V.GreaterOrEqual(18)],
        "ni_number": [V.Size(6)],
    "devices": [
        "UDID": [V.Present]

To validate an object against a schema do:

var user:[String:AnyObject] = [
    "timestamp": 123123,
    "sourceId" : "XDUUSD-1",
    "userInfo" : [
        "email": "[email protected]",
        "age"  : 17,
        "ni_number": "ABCDEF"],
    "devices": [
        ["name": "iPhone"],
        ["name": "iPad", "UDID": "XYX"]

var err:NSError? = V.validate(schema, object: user)

The userInfo field within NSError contains a Dictionary that contains errors for all the fields that failed validation. If the value of the field itself is an array, the labels are postfixed with a .x (eg: devices.0).

//println(err?.userInfo) will result in the following:
[devices.0: {
    UDID = ("is required.");
}, userInfo: {
    age = ("must be greater than or equal to 18");


You can add your own validators to extend SchemaValidator. All you need to do is to make sure your validator conforms to (AnyObject?) -> (Bool,String?).

The optional param AnyObject? is the value for the key being validated.
The object returned should be a tuple containing a Bool that specifies whether validation failed (false) or passed (true) and an optional error message. Do make sure that you return a legible error message when the validation fails.

Custom Error Messages

If you wish to override the default error messages, you can do so by setting SchemaValidator.messageProvider with a closure that conforms to (forKey:String) -> String.

Support for error messages are very basic at the moment. Im working on making this better. Expect an update soon.


Contributions to this library will be greatly appreciated. If you write a validator that you think will be useful to others, please contribute via pull request.

All I ask is for you to provide your validators as an extension to SchemaValidator. (see: DefaultValidators.swift)


Sathyavijayan Vittal, [email protected]


SchemaValidator is available under the MIT license. See the LICENSE file for more info.

Latest podspec

    "name": "SchemaValidator",
    "version": "0.1.0",
    "summary": "Schema based library to validate JSON like objects for Swift.",
    "description": "                        You can use SchemaValidator to validate JSON like dictionary objects (for eg: anything that conforms to [NSObject:AnyObject] in Swift.n                        See README for more detail and usage.nnn",
    "homepage": "",
    "license": "MIT",
    "authors": {
        "Sathyavijayan Vittal": "[email protected]"
    "source": {
        "git": "",
        "tag": "0.1.0"
    "platforms": {
        "ios": "8.0"
    "requires_arc": true,
    "source_files": "Pod/Classes/**/*",
    "resource_bundles": {
        "SchemaValidator": [

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