# PaymentExpress Developer Portal Documentation

> Documentation for PaymentExpress Developer Portal

## Guides: Integration Basics
- [Integration Overview](https://docs.gsg.tech/docs/getting-started.md)
- [Which Integration Is Right For You?](https://docs.gsg.tech/docs/why-choose-your-integration-type.md)
- [Getting Connected and Authenticated](https://docs.gsg.tech/docs/getting-connected-and-authenticated.md): A Guide for helping you authenticate and check your connection to the PaymentExpress APIs.

## Guides: Online Payments
- [Online Payment Solutions](https://docs.gsg.tech/docs/taking-online-payments.md): An overview of Online Payment Solutions with PaymentExpress
- [Taking Online Payments: Hosted Checkout](https://docs.gsg.tech/docs/creating-a-cart-handoff.md)
- [Taking Online Payments: Embedded Checkout](https://docs.gsg.tech/docs/embedded-checkout.md)
  - [Try Out Embedded Checkout!](https://docs.gsg.tech/docs/try-out-embedded-checkout.md)
  - [Delayed Capture](https://docs.gsg.tech/docs/delayed-capture.md)
  - [Content Security Policy Guide](https://docs.gsg.tech/docs/content-security-policy-guide.md)
  - [Digital Wallet Domain Verification](https://docs.gsg.tech/docs/digital-wallet-domain-verification.md)
  - [Saved Payment Methods](https://docs.gsg.tech/docs/saved-payment-methods.md)

## Guides: In Person Payments
- [Creating an In Person Cart Handoff](https://docs.gsg.tech/docs/creating-an-otc-cart-handoff.md)
- [Hosted In Person Checkout](https://docs.gsg.tech/docs/online-checkout-otc.md)
- [Embedded In Person Checkout](https://docs.gsg.tech/docs/embedded-otc-checkout.md)

## Guides: Voice Payments
- [Taking Payments by Voice](https://docs.gsg.tech/docs/taking-payments-by-voice.md): An overview of the workflow to take payments by voice (IVR) using PaymentExpress.

## Guides: Reconciliation
- [Payment Activity File](https://docs.gsg.tech/docs/payment-activity-file.md)

## Guides: Post-Payment Operations
- [Receipt Generation](https://docs.gsg.tech/docs/receipt-generation.md)

## Guides: Testing And support
- [Test Payment Information](https://docs.gsg.tech/docs/test-tenders.md)

## API Reference: PaymentExpress Client API
- Authentication
  - [Fetch Auth Token](https://docs.gsg.tech/reference/requestjwt.md): OAuth2 Client Credentials request for fetching a JavaScript Web Token (JWT), which can then be used for authorization of further requests against the API.  After retrieving a JWT, it is a best…
- Online Checkout
  - [Create Online Checkout Redirect](https://docs.gsg.tech/reference/createcart.md): The Online Cart Creation request will be used to build the subsequent cart in the redirect / checkout page.  The cart response will indicate the URL the user should be directed to in order to…
  - [Check Online Cart Status](https://docs.gsg.tech/reference/getcartinfo.md): Allows for a client to fetch the status of a given online cart, including if a payment has been made for this cart. NOTE: Carts may be expired from the system after 30 days, resulting in a 404 upon…
  - [Discard Abandoned Cart](https://docs.gsg.tech/reference/deletecart.md): Allows for a client to discard an abandoned online cart.
  - [Create Authorization-Only Cart](https://docs.gsg.tech/reference/createauthorizationcart.md): Creates an online cart in authorize-only mode.  Completing an authorize-only cart will store the customer's payment tender without immediately charging them.  The customer's tender is captured…
  - [Capture Authorized Cart Payment](https://docs.gsg.tech/reference/captureauthorizationcart.md): Captures a previously authorized cart payment.  After an authorization-only cart has been completed by the customer, the integrator backend can use this endpoint to capture the payment and charge the…
  - [Get Fees for Online Checkout](https://docs.gsg.tech/reference/getonlinecartfees.md): Calculates the fees that would be charged for each supported payment tender type given the same cart input used to create an online checkout.  Returns fees for all applicable tender types (credit…
- Hosted In Person Checkout
  - [Create OTC Checkout Redirect](https://docs.gsg.tech/reference/createotccart.md): The OTC Cart Creation request will be used to build the subsequent cart in the redirect / checkout page.  The cart response will indicate the URL the user should be directed to in order to complete…
  - [Check OTC Cart Status](https://docs.gsg.tech/reference/getotccart.md): Allows for a client to fetch the status of a given over-the-counter cart, including if a payment has been made for this cart.
- Embedded In Person Checkout
  - [Embedded In Person Cart Creation](https://docs.gsg.tech/reference/createpinpadcheckout.md): This endpoint allows for creation of new embedded in person carts to be checked out via API.
  - [Embedded In Person Cart Status Lookup](https://docs.gsg.tech/reference/getinpersoncartstatus.md): Allows for a client to fetch the status of a given embedded in person cart.
  - [Embedded In Person PINPad Activation Status Request](https://docs.gsg.tech/reference/getpinpadactivationstatus.md): Allows for a client to fetch the status of a given embedded in person activation. For integrated solutions (Grant Street Windows Application), target the localhost. For semi-integrated solutions…
  - [PIN Pad Activation](https://docs.gsg.tech/reference/activatepinpadcheckout.md): Activates the PIN pad to take payment for the given cart. For integrated solutions (Grant Street Windows Application), target the localhost. For semi-integrated solutions (triPOS, Datacap), target…
  - [Cancel Embedded In Person Cart Checkout](https://docs.gsg.tech/reference/cancelcartcheckout.md): Allows for a client to cancel an incomplete embedded in person cart checkout.
  - [Embedded In Person ECheck Payment for Cart](https://docs.gsg.tech/reference/checkoutpinpadcartecheck.md): This endpoint allows for payment for a embedded in person cart using an electronic check tender.
  - [Discard Abandoned Embedded In Person Cart](https://docs.gsg.tech/reference/deleteinpersoncart.md): Allows for a client to discard an abandoned embedded in person cart.
  - [Display PIN Pad home screen](https://docs.gsg.tech/reference/displaypinpadhome.md): Instructs the Grant Street Windows Application to display the PIN pad home screen.
- Voice Based Checkout
  - [Voice-Based Cart Creation](https://docs.gsg.tech/reference/createvoicecart.md): This endpoint allows for creation of new voice-based carts to be checked out.
  - [Voice-Based Item Lookup](https://docs.gsg.tech/reference/voiceitemlookup.md): This endpoint allows for looking up items that can be payed for
  - [Voice-Based Cart Status](https://docs.gsg.tech/reference/voicecartstatus.md): This endpoint allows for checking the state of a voice-based cart.
  - [Voice-Based Card Payment for Cart](https://docs.gsg.tech/reference/checkoutvoicecartcard.md): This endpoint allows for payment for a voice-based cart using a card tender.
  - [Voice-Based ECheck Payment for Cart](https://docs.gsg.tech/reference/checkoutvoicecartecheck.md): This endpoint allows for payment for a voice-based cart using an electronic check tender.
  - [Cart Creation for Item Lookup Carts](https://docs.gsg.tech/reference/createvoicelookupcart.md): This endpoint allows for creation of new voice-based cart containing items from an item lookup to be checked out.
  - [Discard Abandoned Voice Cart](https://docs.gsg.tech/reference/deletevoicecart.md): Allows for a client to discard an abandoned voice-based cart.
- Post-Payment
  - [Look Up Payment](https://docs.gsg.tech/reference/getpaymentinfo.md): Provides clients with the ability to look up a particular payment, including its current state, amounts, items, etc.
  - [Get Receipt Details for Payment](https://docs.gsg.tech/reference/getpaymentreceiptdetails.md): This endpoint offers a caller the ability to gather all the necessary information to produce a valid receipt for a given payment.
  - [Reverse Payment](https://docs.gsg.tech/reference/reversepayment.md): The PaymentExpress back-office application allows users to initiate voids and refunds of card transactions. A void is a same-day reversal that stops money from moving. A refund is an after-same-day…
  - [Reverse Payment Item](https://docs.gsg.tech/reference/reverseitem.md): Allows the reversal or void of the full or partial amount charged against a particular item on a payment. Item-level reversals support partial reversals by specifying an amount in the request body.…
  - [Reverse Payment by Fund Categories](https://docs.gsg.tech/reference/reversebyfundcategories.md): Allows the reversal or void of the full or partial amount charged against one or more fund categories on a payment. Fund category reversals support partial reversals by specifying an amount as part…
- Tax Lookups
  - [Tax Item Lookup by Address](https://docs.gsg.tech/reference/taxitemlookupbyaddress.md): This endpoint allows for looking up tax items (property or business) by address.
  - [Tax Item Lookup by Identifier](https://docs.gsg.tech/reference/taxitemlookupbyidentifier.md): This endpoint allows for looking up tax items (property or business) by identifier.
  - [Cart Creation for Tax Lookup Carts](https://docs.gsg.tech/reference/createtaxlookupcart.md): This endpoint allows for creation of a new in-person cart containing items from a tax item lookup to be checked out.
- Misc
  - [Service Check](https://docs.gsg.tech/reference/ping-1.md): Allows a client to validate that they can reach the PaymentExpress API successfully, including validating their authorization configuration.
- Payment Links
  - [Create a Payment Links cart](https://docs.gsg.tech/reference/createpaymentlinkcart.md): Creates a pre-populated cart, a link to which can be sent in a Payment Link message
  - [Send a Payment Links Email](https://docs.gsg.tech/reference/sendpaymentlinkemail.md): Sends a Payment Links email to the customer for the given cart.
  - [Send a Payment Links SMS](https://docs.gsg.tech/reference/sendpaymentlinksms.md): Sends a Payment Links SMS to the customer for the given cart.
  - [Discard Abandoned Payment Links Cart](https://docs.gsg.tech/reference/deletepaymentlinkscart.md): Allows for a client to discard an abandoned Payment Links cart.
  - [Get SMS Verbal Opt-in Prompt](https://docs.gsg.tech/reference/getsmsverbaloptinprompt.md): Retrieves the SMS verbal opt-in prompt for the given location. This prompt is used by cashiers to request verbal consent from customers to receive SMS messages.
  - [Create Customer Consent to Receive SMS Messages for Payment Links](https://docs.gsg.tech/reference/createsmsuserconsent.md): Creates a record of customer consent to receive SMS messages for Payment Links for a given phone number.
  - [Get Existing Customer Consent to Receive SMS Messages for Payment Links](https://docs.gsg.tech/reference/getsmsuserconsent.md): Retrieves an existing record of customer consent to receive SMS messages for Payment Links for a phone number. Returns the consent details if found, or 404 if no consent exists.