Auth Stream Access (ASA)
Learn about providing your own authorization rules by registering an endpoint.
Authorization Stream Access (ASA) provides the ability to make custom transaction approval decisions through an HTTP interface to the ISO 8583 message stream.
ASA requests are delivered as an HTTP POST during authorization. The ASA request body adheres to the Lithic transaction schema, with some additional fields added for use in decisioning. A response should be sent with HTTP response code 200 and the approval decision in the response body. This response is converted by Lithic back into ISO-8583 format and forwarded to the network.
Testing in sandbox
In sandbox, users can self-enroll and disenroll in ASA. In production, onboarding requires manual approval and setup.
Pre-ASA auth request checks
For ASA-enabled users, Lithic will only perform very basic pre-authorization checks before sending the request out (decrypt EMV cryptogram, validate PAN, validate CVV/PIN if present). For example, we won't check auth rules such as
MERCHANT_LOCKED
or spending limits. You must supply your own auth rules.Lithic will not send ASA requests to your endpoint if the message fails basic pre-authorization checks. For a list of all pre-authorization checks, please reference Transaction.result.
Set up an ASA responder in under 10 minutes!
Full details on responding to ASA requests follow, but to get you up and running quickly we’ve also provided sample application for creating an auth stream access webhook with AWS API Gateway and Lambda, managed via AWS Serverless Application Model (SAM).
- NodeJS example: https://github.com/lithic-com/asa-demo-node
- Python example: https://github.com/lithic-com/asa-demo-python
Schema
Lithic Request
Similar to Transaction object in Transaction Webhooks with additional properties.
{
"amount": Integer,
"acquirer_fee": Integer,
"authorization_amount": Integer,
"avs": {
"address": String,
"zipcode": String
},
"card": Card,
"cardholder_authentication": CardholderAuthentication,
"cash_amount": Integer,
"conversion_rate": Integer,
"created": String,
"events": [
Event
],
"funding": [
{
"amount": Integer,
"token": String,
"type": String
}
],
"merchant_amount": Integer,
"merchant_currency": String,
"merchant": Merchant,
"network": String,
"pos": {
"terminal": {
"attended": Boolean,
"operator": String,
"on_premise": Boolean,
"card_retention_capable": Boolean,
"pin_capability": String,
"type": String,
"partial_approval_capable": Boolean
},
"entry_mode": {
"pan": String,
"pin_entered": Boolean,
"cardholder": String,
"card": String
}
},
"settled_amount": Integer,
"status": String,
"token": String,
"token_info": {
"wallet_type": Enum{}
}
}
acquirer_fee | Fee (in cents) assessed by the merchant and paid for by the cardholder. Will be zero if no fee is assessed. Rebates may be transmitted as a negative value to indicate credited fees. |
amount | Authorization amount of the transaction (in cents), including any acquirer fees. This may change over time. |
authorization_amount | The base transaction amount (in cents) plus the acquirer fee field. This is the amount the issuer should authorize against unless the issuer is paying the acquirer fee on behalf of the cardholder. |
avs | Contains address validation (AVS) information collected by the merchant to be verified by the issuer. |
card | See Cards Schema. |
cardholder_authentication | See Cardholder Authentication Schema. |
cash_amount | The portion of the transaction requested as cash back by the cardholder, and does not include any acquirer fees. The amount field includes the purchase amount, the requested cash back amount, and any acquirer fees.If no cash back was requested, the value of this field will be 0 , and the field will always be present. |
conversion_rate | If the transaction was requested in a currency other than the settlement currency, this field will be populated to indicate the rate used to translate the merchant_amount to the amount . Note that the merchant_amount is in the local currency and the amount is in the settlement currency. |
created | Date and time when the transaction first occurred. |
events | A list of all events that have modified this transaction. |
funding | A list of objects that describe how this transaction was funded, with the amount represented in cents. A reference to the funding source for the card that made this transaction may appear here and the token will match the token for the funding source in the card field. If any promotional credit was used in paying for this transaction, its type will be PROMO . |
merchant | See Merchant Schema. |
merchant_amount | The amount that the merchant will receive, denominated in merchant_currency and in the smallest currency unit. Note the amount includes acquirer_ fee , similar to authorization_amount . It will be different from authorization_amount if the merchant is taking payment in a different currency. |
merchant_currency | ISO 4217 alpha 3 code for the currency of the transaction. |
network | Card network of the authorization. Can be INTERLINK , MAESTRO , MASTERCARD , VISA , or UNKNOWN . |
network_risk_score | Network-provided score assessing risk level associated with a given authorization. Scores are on a range of 0-999, with 0 representing the lowest risk and 999 representing the highest risk. Only available on authorizations with status of AUTHORIZATION (i.e., dual message purchase authorizations), and currently on Mastercard BINs. |
pos | See Point of Sale definition. |
settled_amount | Amount (in cents) of the transaction that has been settled, including any acquirer fees. This may change over time. |
status | Available to all users:AUTHORIZATION is a dual message purchase authorization.FINANCIAL_AUTHORIZATION is a single message authorization request with no subsequent clearing.BALANCE_INQUIRY is a $0 authorization that includes a request for the balance held on the card.Only available to users with credit decisioning via ASA enabled: CREDIT_AUTHORIZATION is a dual message request from a merchant to authorize a refund or credit.FINANCIAL_CREDIT_AUTHORIZATION is a single message request from a merchant to credit funds with no subsequent clearing. |
token | Globally unique identifier for the transaction. |
token_info.wallet_type | Will be present if the transaction is tokenized, and absent for a physical or virtual non-tokenized transaction. The wallet_type field will indicate the source of the token. Possible token sources include digital wallets (Apple, Google, or Samsung Pay), merchant tokenization, and “other” sources like in-flight commerce. Masterpass is not currently supported and is included for future use. |
User Response
{
"result": String,
"token": String,
"avs_result": String,
"balance": {
"amount": Integer,
"available": Integer
}
}
result | APPROVED to accept the authorization. Any other response will decline the authorization. See ASA Response Result for possible values. |
token | The transaction token from the ASA request. |
avs_result (optional) | The ASA responder may return an address verification (AVS) match indicator for evaluation by the acquirer. See AVS Response Result for possible values. The merchant can choose whether to submit the transaction in the case of an approval with AVS failure. |
balance (optional) | Respective available amount and settled amount values (in cents). These values can be used by merchants for authorization decisions as well as balance display at point of sale or ATM. |
Response Guidelines
Response Time
If no response is received within 5 seconds, the transaction will be declined for the cardholder. Every party involved in the transaction processing flow takes a certain amount of time, and the merchant or the acquirer will time out at some point. We recommend responding within 3 seconds. If your ASA responder takes longer than that, you may see a higher percentage of transactions being voided shortly after you have approved them.
AVS Matching
Address verification (AVS) checks two pieces of information, the postal code and the billing street address. Responding with AVS is optional. If AVS is present and a response is not received, Lithic will return AVS validated.
If AVS attributes aren’t included in the authorization, any AVS response result will be ignored.
Returned Balances
BALANCE_INQUIRY
ASA messages require a settled and available amount to be returned.
amount
represents the balance held on the card.available
represents the balance available for the cardholder to spend. This is calculated as the settled amount minus any pending authorizations on the card.
If no balance is returned, Lithic will return $0 to the network as a response.
Enumerations
Point of Sale
terminal.attended | True if a clerk is present at the sale. |
terminal.on_premise | True if the sale was made at the place of business (vs. mobile). |
terminal.operator | The person that is designed to swipe the card, possible values: CARDHOLDER , CARD_ACCEPTOR , ADMINISTRATIVE . |
terminal.partial_approval_capable | True if the terminal is capable of partial approval. Partial approval is when part of a transaction is approved and another payment must be used for the remainder. Example scenario: A $40 transaction is attempted on a prepaid card with a $25 balance. If partial approval is enabled, $25 can be authorized, at which point the POS will prompt the user for an additional payment of $15. See Partial Approval for more information on how to partially approve authorizations. |
terminal.pin_capability | Status of whether the POS is able to accept PINs, possible values: CAPABLE , INOPERATIVE , NOT_CAPABLE , UNSPECIFIED . |
terminal.type | POS type, see POS Type for possible values. |
entry_mode.card | Card status, possible values: PRESENT , NOT_PRESENT . |
entry_mode.cardholder | Cardholder Presence status, see Cardholder Presence Status for possible values. |
entry_mode.pan | Method of entry for the PAN, see Method of Entry for possible values. |
entry_mode.pin_entered | True if the PIN was entered. |
POS Type
ATM
AUTHORIZATION
COUPON_MACHINE
DIAL_TERMINAL
ECOMMERCE
ECR
(electronic cash register)FUEL_MACHINE
HOME_TERMINAL
MICR
OFF_PREMISE
PAYMENT
PDA
PHONE
POINT
POS_TERMINAL
SELF_SERVICE
TELEVISION
TELLER
TRAVELERS_CHECK_MACHINE
VENDING
VOICE
Method of Entry
Method of entry | Description |
AUTO_ENTRY | PAN auto-entry via server (issuer, acquirer, or third party vendor system) |
BAR_CODE | PAN auto-entry via bar code or QR code reader |
CONTACTLESS | Contactless via chip |
CREDENTIAL_ON_FILE | Credential on file |
ECOMMERCE | PAN or token entry via electronic commerce |
ERROR_KEYED | Chip card or chip-capable terminal was unable to process the transaction using the data on the chip or magnetic stripe, the PAN was entered manually, or the acquirer is not certified to process chip fallback to magnetic stripe |
ERROR_MAGNETIC_STRIPE | Chip card or chip-capable terminal was unable to process the transaction using the data on the chip, therefore the PAN was entered via magnetic stripe |
ICC | PAN auto-entry via chip |
KEY_ENTERED | Manually keyed |
MAGNETIC_STRIPE | Magnetic stripe entry |
MANUAL | Manual entry |
OCR | PAN auto-entry via OCR |
SECURE_CARDLESS | Secure cardless entry |
UNSPECIFIED | Unspecified method of entry |
UNKNOWN | Unknown or unmapped method of entry |
Cardholder Presence Status
DEFERRED_BILLING
ELECTRONIC_ORDER
INSTALLMENT
MAIL_ORDER
NOT_PRESENT
PRESENT
REOCCURRING
TELEPHONE_ORDER
ASA Response Result
Decline reason | Description |
ACCOUNT_INACTIVE | Same as CARD_PAUSED , will be deprecated in future versions. |
AVS_INVALID | Prevent acquirers from approving the transaction despite incorrect AVS. Note: AVS response is not required for this decline type. |
CARD_CLOSED | Card is permanently closed. Use the Update Card to close card after sending this response. |
CARD_PAUSED | Card is not yet activated or in a paused state. Use the Update Card to pause card after sending this response. |
INSUFFICIENT_FUNDS | User has insufficient funds. Acquirers may retry the transaction at a later time. |
UNAUTHORIZED_MERCHANT | Can be used for restricted MCCs, countries, or transaction types (e.g. money transfer transactions). |
VELOCITY_EXCEEDED | Transaction exceeds issuer-set velocity limits. Acquirers may retry the transaction at a later date. |
AVS Response Result
FAIL |
MATCH |
MATCH_ADDRESS_ONLY |
MATCH_ZIP_ONLY |
Wallet Type
Value | Description |
---|---|
MASTERPASS | Not currently used, reserved for future use. |
APPLE_PAY | Transaction originated from an Apple Pay wallet. |
GOOGLE_PAY | Transaction originated from a Google Pay wallet. |
SAMSUNG_PAY | Transaction originated from a Samsung Pay wallet. |
MERCHANT | Transaction originated from a merchant token. |
OTHER | Transaction originated from an unknown but tokenized source. |
ASA Webhook Verification
Lithic enables webhook verification for ASA requests using the same methodology that is used in our Events API and webhooks. Please refer to this page for detailed implementation steps and example code you can use.
By default, the three headers (webhook-id
, webhook-timestamp
, and webhook-signature
) are not included in ASA requests. To begin receiving these headers, call the retrieve the ASA HMAC secret key endpoint. Within minutes, the headers will begin appearing in your ASA requests. To rotate your key, call the rotate the ASA HMAC secret key endpoint. Both of these endpoints (as well as simulated ASA requests) are available in Sandbox, and we recommend testing your implementation of webhook verification in the Sandbox environment first.
You can also retrieve these keys on the account page of the Lithic Dashboard. Note that a Production key will only appear once your card program is configured by your Implementation Manager to have ASA enabled, and a Sandbox key will only appear once you have enrolled in Sandbox ASA via the Enroll ASA endpoint.
Updated 15 days ago