Easily accept payments on iOS
Objective-C Ruby C++
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PaymentKit Example



PaymentKit is a utility library for writing payment forms in iOS apps.

Just add PKView to your application, and it'll take care accepting card numbers, expiry, cvc and zip. Alternatively, we've provided a bunch of classes that you can use yourself to add formatting, validation and restricting input of UITextFields.

In short, PaymentKit should greatly simplify your life when dealing with iOS payments.


For purchases related to the app, such as premium features, Apple's TOS require that you use their native In-App Purchase API. PaymentKits is only for purchasing products or services outside the app.


Install with CocoaPods

CocoaPods is a library dependency management tool for Objective-C. To use PaymentKit with CocoaPods, simply add the following to your Podfile and run pod install:

pod 'PaymentKit', :git => 'https://github.com/stripe/PaymentKit.git'

Install by adding files to project

  1. Clone this repository
  2. In the menubar, click on 'File' then 'Add files to "Project"...'
  3. Select the 'PaymentKit' directory in your cloned PaymentKit repository
  4. Make sure "Copy items into destination group's folder (if needed)" is checked"
  5. Click "Add"

PaymentKit View

1) Add the QuartzCore framework to your application.

2) Create a new ViewController, for example PaymentViewController.

#import <UIKit/UIKit.h>
#import "PKView.h"

@interface PaymentViewController : UIViewController <PKViewDelegate>
@property IBOutlet PKView* paymentView;

Notice we're importing PKView.h, the class conforms to PKViewDelegate, and lastly we have a paymentView property of type PKView.

3) Instantiate and add PKView. We recommend you use the same frame.

- (void)viewDidLoad
    [super viewDidLoad];

    self.paymentView = [[PKView alloc] initWithFrame:CGRectMake(15, 25, 290, 55)];
    self.paymentView.delegate = self;
    [self.view addSubview:self.paymentView];

4) Implement PKViewDelegate method paymentView:withCard:isValid:. This gets passed a PKCard instance, and a BOOL indicating whether the card is valid. You can enable or disable a navigational button depending on the value of valid, for example:

- (void) paymentView:(PKView*)paymentView withCard:(PKCard *)card isValid:(BOOL)valid
    NSLog(@"Card number: %@", card.number);
    NSLog(@"Card expiry: %lu/%lu", (unsigned long)card.expMonth, (unsigned long)card.expYear);
    NSLog(@"Card cvc: %@", card.cvc);
    NSLog(@"Address zip: %@", card.addressZip);

    // self.navigationItem.rightBarButtonItem.enabled = valid;

That's all! No further reading is required, unless you want more flexibility by using the raw API. For more, please see the included example.

Full API

API Example

// Format a card number
[[PKCardNumber cardNumberWithString:@"4242424242424242"] formattedString]; //=> '4242 4242 4242 4242'
[[PKCardNumber cardNumberWithString:@"4242424242"] formattedString]; //=> '4242 4242 42'

// Amex support
[[PKCardNumber cardNumberWithString:@"378282246310005"] formattedString]; //=> '3782 822463 10005'
[[PKCardNumber cardNumberWithString:@"378282246310005"] cardType] == PKCardTypeAmex; //=> YES

// Check a card number is valid using the Luhn algorithm
[[PKCardNumber cardNumberWithString:@"4242424242424242"] isValid]; //=> YES
[[PKCardNumber cardNumberWithString:@"4242424242424243"] isValid]; //=> NO

// Check to see if a card expiry is valid
[[PKCardExpiry cardExpiryWithString:@"05 / 20"] isValid]; //=> YES
[[PKCardExpiry cardExpiryWithString:@"05 / 02"] isValid]; //=> NO

// Return a card expiry's month
[[PKCardExpiry cardExpiryWithString:@"05 / 02"] month]; //=> 5

API Delegates

Included are a number of UITextFieldDelegate delegates: PKCardCVCDelegate, PKCardExpiryDelegate and PKCardNumberDelegate. You can set these as the delegates of UITextField inputs, which ensures that input is limited and formatted.


+ (id) cardNumberWithString:(NSString *)string

- (id) initWithString:(NSString *)string

Create a PKCardNumber object, passing a NSString representing the card number. For example:

PKCardNumber* cardNumber = [PKCardNumber cardNumberWithString:@"4242424242424242"];

- (PKCardType)cardType

Returns a PKCardType representing the card type (Visa, Amex etc).

PKCardType cardType = [[PKCardNumber cardNumberWithString:@"4242424242424242"] cardType];

if (cardType == PKCardTypeAmex) {


Available types are:


- (NSString *)string

Returns the card number as a string.

- (NSString *)formattedString

Returns a formatted card number, in the same space format as it appears on the card.

NSString* number = [[PKCardNumber cardNumberWithString:@"4242424242424242"] formattedString];
number //=> '4242 4242 4242 4242'

- (NSString *)formattedStringWithTrail

Returns a formatted card number with a trailing space, if appropriate. Useful for formatting UITextField input.

- (BOOL)isValid

Helper method which calls isValidLength and isValidLuhn.

- (BOOL)isValidLength

Returns a BOOL depending on whether the card number is a valid length. Takes into account the different lengths of Amex and Visa, for example.

- (BOOL)isValidLuhn

Returns a BOOL indicating whether the number passed a Luhn check.

- (BOOL)isPartiallyValid

Returns a BOOL indicating whether the number is too long or not.


+ (id) cardCVCWithString:(NSString *)string

- (id) initWithString:(NSString *)string

Returns a PKCardCVC instance, representing the card CVC. For example:

PKCardCVC* cardCVC = [PKCardCVC cardCVCWithString:@"123"];

- (NSString*)string

Returns the CVC as a string.

- (BOOL)isValid

Returns a BOOL indicating whether the CVC is valid universally.

- (BOOL)isValidWithType:(PKCardType)type

Returns a BOOL indicating whether the CVC is valid for a particular card type.

- (BOOL)isPartiallyValid

Returns a BOOL indicating whether the cvc is too long or not.


+ (id)cardExpiryWithString:(NSString *)string

- (id)initWithString:(NSString *)string

Create a PKCardExpiry object, passing a NSString representing the card expiry. For example:

PKCardExpiry* cardExpiry = [PKCardExpiry cardExpiryWithString:@"10 / 2015"];

- (NSString *)formattedString

Returns a formatted representation of the card expiry. For example:

[[PKCardExpiry cardExpiryWithString:@"10/2015"] formattedString]; //=> "10 / 2015"

- (NSString *)formattedStringWithTrail

Returns a formatted representation of the card expiry, with a trailing slash if appropriate. Useful for formatting UITextField inputs.

- (BOOL)isValid

Returns a BOOL if the expiry has a valid month, a valid year and is in the future.

- (NSUInteger)month

Returns an integer representing the expiry's month. Returns 0 if the month can't be determined.

- (NSUInteger)year

Returns an integer representing the expiry's year. Returns 0 if the year can't be determined.