BlockChyp Developer Center

Welcome to BlockChyp’s developer documentation center.

Getting Started

To get started with BlockChyp, sign up for a developer account on the BlockChyp Web Site and order a BlockChyp Developer Kit. The kit will include a fully functioning payment terminal, along with chip, mag stripe, and gift card test cards.

Next, examine the list of SDKs and Clients and follow the instructions for your technology ecosystem.

SDKs and Clients

All supported BlockChyp SDKs are open source and hosted on Github.

What If My Platform Isn’t Listed?

If we don’t have a client or SDK for your language or platform listed, you have plenty of other options.

Use The Rest API’s

The SDKs aren’t required. We just provide them to make things a little bit simpler and faster for developers. The BlockChyp Gateway and all BlockChyp terminals run simple REST APIs you can integrate with directly. Checkout the Terminal REST API Reference and the Payment Gateway REST API Reference for more information.

Use The Command Line

The BlockChyp Go SDK includes additional build scripts that create Windows and Linux command line executables that can be invoked via shell commands.

More documentation on the command line can be found on the Go SDK’s Github Page

Build An SDK

If you’re using a modern programming language that we just haven’t gotten around to yet (like Ruby, Swift, or Rust), we’d prefer to work with you on creating an open source SDK for your platform. This allows other developers in your technology ecosystem to benefit going forward.

To develop your own SDK, check out the SDK Developers Guide for some high level concepts and guidance. Then use the REST API references as you work through the various terminal and gateway transactions.

The Go SDK is open source and serves as a fairly good example of what should go into a new SDK.

If you’re thinking of developing a new SDK, feel free to contact us at We’ll talk through the trade offs with you and maybe pitch in ourselves.

Standard Codes

BlockChyp has a set of standard strings for things like Card Types and Entry Methods.

If there were industry wide standards for this sort of thing, BlockChyp would gladly embrace them, but unfortunately that’s not the way things work. The lists below enumerate the keys you’ll need to bake into your system as constants for BlockChyp.

Card Types

This list enumerates the codes for card types and payment methods.

AMEX:American Express
DINERS:Diners Club International
CUP:China Union Pay
JCB:Japan Card Bureau
BC_GIFT:BlockChyp Blockchain Gift Card

Entry Methods

This list enumerates the codes for entry methods.

CHIP:EMV chip contact
SWIPE:Magnetic Stripe Read
KEYED:Manually keyed
ANDROID:Android Pay
SAMSUNG:Samsung Pay
WALLET:Mobile Crypto Wallet

Currency Codes

This list enumerates the currency codes defined by BlockChyp.

USD:United States Dollar
BTC:Bitcoin Main Fork
BCP:BlockChyp’s internal cryptocurrency

Gift Cards

The BlockChyp gift card system is quite a bit different from conventional gift cards. Conventional gift cards, just like credit cards, typically rely on 16 digit primary account numbers. These numbers are relatively easy to guess via brute force, which makes them vulnerable to a host of security problems. But unlike conventional credit card numbers, gift cards aren’t protected by PCI and often implemented by white listing gift card BIN ranges. They’re usually the most insecure part of any payment system.

BlockChyp gift cards do have 16 digit numbers printed on them for familiarity and convenience, but these numbers are for identification purposes only. Under the hood every BlockChyp gift card has a unique set of P256 elliptic curve keys.

The elliptic curve keys are used to open a new blockchain when new gift cards are activated and as the card is redeemed and recharged, the keys are used to sign transactions. This means that shared secrets (i.e. primary account numbers) are never transmitted over the network with a BlockChyp gift card transaction. The transaction could be intercepted or sent in the clear and not compromise the gift card.

We’ve gone through a lot of trouble to insulate developers from dealing with blockchain details. BlockChyp gift card transactions are like any other transaction with the exception of how gift cards are identified. Authorization requests for gift card transactions return the elliptic curve public key in the publicKey field. If you need to keep track of gift cards in your SaaS or point-of-sale systems, use the public key. A remaining balance is also returned with every gift card authorization.

Although you don’t have to understand blockchain technology to work with BlockChyp gift cards, the merchant and developer dashboards to expose methods of browsing and viewing the raw blockchain for the curious.

Third Party Gift Cards

For merchants with existing gift card liability, these gift cards can be easily imported into BlockChyp. Simply provide your liability report to your BlockChyp representative. BlockChyp will review the liability data and import the gift cards into your BlockChyp account

Third party gift cards are redeemed just like BlockChyp gift cards. Simply swipe them on the terminal at the present card prompt.

BIN Range White Listing

In the event that developers need to process certain card types outside of BlockChyp, it is possible to white list BIN ranges and have the raw card data returned. Configuring a merchant account for white listing does require a security review by BlockChyp. If you need to white list a BIN range, contact BlockChyp support to complete the setup.

Once the configuration is complete, white listed card responses will look this like this…

White List Sample Response:

  "responseDescription": "WHITELISTED",
  "transactionId": "",
  "transactionRef": "26476425504",
  "transactionType": "charge",
  "timestamp": "",
  "tickBlock": "",
  "test": false,
  "approved": false,
  "authCode": "",
  "sigFile": "",
  "receiptSuggestions": {
    "authorizedAmount": "0",
    "transactionType": "charge",
    "cashBackAmount": "0"
  "partialAuth": false,
  "altCurrency": false,
  "fsaAuth": false,
  "currencyCode": "",
  "requestedAmount": "0",
  "authorizedAmount": "0",
  "tipAmount": "0",
  "taxAmount": "0",
  "requestedCashBackAmount": "0",
  "authorizedCashBackAmount": "0",
  "whiteListedCard": {
    "bin": "778273",
    "track1": "B7782730094745057^SQUARE GIFT CARD^99127069345",
    "track2": "7782730094745057=99127069345",
    "pan": "7782730094745057"
  "storeAndForward": false

In order to make the customer experience seamless, a white listed response will return to the POS while leaving the terminal screen unchanged. We recommend that developers call the BlockChyp message API to display an approved or declined response on the terminal screen after the white listed card has been processed. This will make the transaction appear to the consumer to have been completed entirely on the terminal.

Receipt Requirements

BlockChyp API responses include information that most developers will use to create printed receipts. Consider the following transaction response, shown here as JSON:

Sample Response:

  "cardHolder":"Test/Card 01              ",
    "merchantName":"Test Merchant",
    "applicationLabel":"VISA CREDIT",

The response includes a number of fields consumers are used to seeing on receipts such as masked PAN and auth code.

It also includes a receiptSuggestions section that collects all EMV fields we recommend putting on your receipts.

Not all card brands have the same requirements, but if you always include the following data elements on all receipts, your receipts will be compliant with all card brand receipt requirements and recommendations.

  • authCode
  • maskedPan
  • AID
  • applicationLabel
  • ARQC
  • TC

Test Cards

All BlockChyp developer kits include a set of test cards, but BlockChyp is designed to be compatible with most common test card sets. Any valid test card can be used with BlockChyp.


This section describes BlockChyp’s default test account behavior. Developers and partners can alter and extend the test card configuration. If these test cards and trigger amounts don’t work as expected, check your adverse event configuration in the BlockChyp dashboard.

Simulating Approvals

The BlockChyp test system will send back an approval response for any valid Visa, Mastercard, American Express, or Discover test card number except as described below.

Adverse Events

We hope for approval in life, but that doesn’t always happen. BlockChyp has an extensible system for simulating adverse events like declines, partial authorizations, and other unexpected responses.

BlockChyp supports the following adverse event types:

decline:Authorization declined by the payment network.
error:Simulates a network or system error.
fraud:Simulates a response flagged for probable fraud.
partial-auth:Simulates a partial authorization in which the authorized amount is less than the requested amount.
timeout:Simulates a transaction that takes a long time to respond, potentially triggering a time out.
no-response:Simulates a transaction that fails to return a response at all.

The table below shows the default trigger conditions for adverse events in BlockChyp. Events can be triggered by either card number or amount. These can be changed or modified for your account via the BlockChyp dashboard.

Event Type Trigger Card Trigger Amount Notes
decline 4111111111111129 201.00  
error 6011000990139424 00.11  
fraud 371449635398431 66.00  
partial-auth 5105105105105100 55.00 Authorized Amount: $25.00
no-response 4111111111111137 72.00 Returns no response.
timeout 5555555555554444 68.00 Gateway hangs for 30 seconds.

Store and Forward Testing

BlockChyp terminals include the ability to store transactions for later authorization in the event of a network outage. To test this feature, ensure your test merchant account has a non-zero floor limit set on the merchant profile. You can then test store and forward by unplugging the terminal from the network in the middle of a transaction or you can simply use a special trigger amount with all sevens (e.g. 0.77, 7.77, 77.77) and the terminal will simulate a network outage and process the transaction as a store and forward transaction.

Terminals attempt to forward offline transactions every two minutes until they are successfully processed. To test a declined store and forward transaction, try running an amount with all sevens below the floor limit with the decline test card.

Running EMV Certification Tests


This section is for advanced developers only. EMV Certification is not required to use BlockChyp.

Merchants and developers who use BlockChyp do not require EMV certification and the default test API provides abbreviated responses suitable for most purposes. But, these simplified responses may not satisfy all the card log requirements for real EMV tests.

If you happen to have a Collis or UL EMV Test Tool and want to run real EMV certification tests against BlockChyp, contact us at We’ll connect your test merchant account to a real EMV certification back end.