Constellation Payments CSIPayPortal Guides
Contact support
Open the portal

Start a merchant application

Board a new merchant in five steps, from business details to review and submit, with everything you need to have ready.

Merchants › Merchant OnboardingPartners and onboarding teams16 stepsVideo walkthrough
Walkthrough video: select play to watch Start a merchant application walkthrough video thumbnail

Have these ready before you start

  • Business details: legal business name, DBA (if any), tax ID, entity type, established date, number of employees, the full business address, and the billing contact's name, email, and phone. Company website is optional.
  • Owner information: for every beneficial owner who owns 25% or more, or who exercises significant control: full name, title, ownership percentage, SSN or SIN, date of birth, phone, email, residential address, driver's license number and state, and a clear image of their government-issued ID.
  • Payment and transaction information: a description of the products or services sold, the Merchant Category Code (MCC), whether you offer subscription or recurring services, average and maximum transaction amounts, monthly card and ACH volumes, projected annual volume, when the customer is charged and the typical delivery time, the refund or return policy, and the percentage split across payment channels (it must total 100%).
  • Banking details: a checking account (used for deposits, fees, refunds, and reversals): bank name, account holder name exactly as it appears on the account, bank or institution number, transit number, and account number, plus a voided check or bank letter as SVG, PNG, JPG, or GIF, no larger than 800 by 400 pixels.
About 10 minutes. With the information ready, the application takes about 10 minutes. Incomplete or incorrect details delay approval. You can select Save as Draft on any screen and come back later.
Before you start. Log in to the portal and use the Accessing switcher to select the partner account the new merchant will belong to. New to this? See Log in and reset your password and Switch between accounts.

01Start the application

1

Open Merchant Onboarding

In the left navigation sidebar, open Management and select Merchant Onboarding.

2

Review the welcome screen

The welcome screen lists what to have ready under Before You Begin and the three-step overview under How It Works. Select Start Application.

The Welcome to CSI Pay screen with the Before You Begin checklist, the How It Works overview, and the Start Application button
The welcome screen. Start Application is in the bottom right.

02Step 1 of 5: Business Information

Three short sections. The Registration Progress panel on the left shows where you are.

3

Section 1 of 3: Business Identity

Enter Legal Business Name, Business DBA Name (optional), Business Tax ID, Established Date, and Number Of Employees. Select Next Section.

Section 1 of 3, Business Identity, with Legal Business Name, Business DBA Name, Business Tax ID, Established Date, and Number Of Employees fields
Business Identity.
4

Section 2 of 3: Contact Information

Enter Billing Contact Name, Business Billing Email, Business Phone, and Company Website (optional). Select Next Section.

Section 2 of 3, Contact Information, with Billing Contact Name, Business Billing Email, Business Phone, and Company Website fields
Contact Information.
5

Section 3 of 3: Business Address

Select Business Entity and Country, then complete Address Line 1, Address Line 2, City, Province, and ZIP Code. Select Continue to Next Step.

Section 3 of 3, Business Address, with Business Entity, Country, Address Line 1, Address Line 2, City, Province, and ZIP Code fields
Business Address.

03Step 2 of 5: Beneficial Owners

Add every owner who holds 25% or more of the business, or who exercises significant control.

6

Add the first owner

If no owners are listed yet, select Add Beneficial Owner.

Step 2 of 5, Beneficial Owners, showing No Owners Added Yet with the Add Beneficial Owner button and a note that any owner with over 25% ownership must be added
No owners added yet.
7

Complete each owner's details

For each owner, complete all of the identity fields and upload a clear image of their government-issued ID.

8

Review the list

Each owner appears as a card. Use Show More to expand the full details, Edit or the delete icon to change or remove an owner, and Add More for additional owners.

Four beneficial owner cards, each with a name, email, Show More link, and edit and delete icons, and the Add More button
The list of added owners. Names shown are test data.
An owner card expanded with Show Less, showing Identity Details such as owner, title, birth date, email, address, ownership percentage, SSN or SIN, phone, ownership duration, and driver's license, and the uploaded ID image
An owner's details expanded, with the ID image. Data shown is test data.
9

Continue

When every owner is added, select Continue to Next Step.

04Step 3 of 5: Payment Profile

Three sections about what the merchant sells and how it takes payment.

10

Section 1 of 3: Products and Services

Describe the products or services, select the Merchant Category Code (MCC), say whether you provide subscription or recurring services and describe them, and answer the surcharging question. Select Next Section.

Section 1 of 3, Products and Services, with the products and services description, Merchant Category Code, subscription and recurring services questions, and the surcharging question
Products and Services.
11

Section 2 of 3: Transaction Information

Enter the average and maximum transaction amounts, average monthly card and ACH volumes, projected total processing volume for the next 12 months, when payment occurs, how long until delivery, the refund policy, and whether you are currently accepting payments. Select Next Section.

Section 2 of 3, Transaction Information, with transaction amount and volume fields, when payment occurs, delivery time, refund policy, and whether payments are currently accepted
Transaction Information.
12

Section 3 of 3: Payment Information

Enter the percentage of volume for each channel: Mail / Telephone Order, Internet, Swipe, and Keyed. The total must equal 100%. Use Reset to start over. Select Continue to Next Step.

Section 3 of 3, Payment Information, with percentage fields for Mail / Telephone Order, Internet, Swipe, and Keyed, and a Total that must reach 100%
Payment Information. The percentages must total 100%.

05Step 4 of 5: Banking Details

The checking account used for deposits, fees, refunds, and reversals.

13

Enter the account

Enter Bank Name, Account Holder Name (it must match the bank account exactly), Bank / Institution Number, Bank Transit Number and confirm it, and Account Number and confirm it.

14

Upload proof of the account

Under Upload Check or Bank Letter, upload a voided check or a bank letter as SVG, PNG, JPG, or GIF, no larger than 800 by 400 pixels. Then select Continue to Next Step.

Step 4 of 5, Banking Details, with Bank Name, Account Holder Name, Bank / Institution Number, Bank Transit Number, Account Number, confirmation fields, and the Upload Check or Bank Letter area
Banking Details, with the upload area at the bottom.

06Step 5 of 5: Review and Submit

15

Check every section

Review Business Details, Beneficial Owners, and the other sections. Use the Edit links to correct anything.

Step 5 of 5, Review and Submit, listing Business Details with Edit links, followed by Beneficial Owners, with Save as Draft, Back, and Submit buttons
Review and Submit. Data shown is test data.
16

Submit

When everything is correct, select Submit. The application is sent for review.

What happens next. You see a confirmation on screen and usually receive an email. CSIPay reviews the information and documents. Once approved, the merchant account is activated and appears under Merchants. If anything is missing or unclear, you will be contacted for more information and the application stays in draft or pending status until it is resolved. Come back to Merchant Onboarding at any time to check status or continue a saved draft.

Key terms

Beneficial owner
Anyone who owns 25% or more of the business, or who exercises significant control over it.
MCC
Merchant Category Code: the four-digit code that classifies what the business sells.
DBA
Doing business as: the name the business trades under, if different from its legal name.
Draft
An application saved before it is submitted. It can be reopened from Merchant Onboarding.
Merchant OnboardingSet up underwriting workflowsOpen guide Merchant AccountsFind and view a merchantOpen guide Account switcherSwitch between accountsOpen guide
Was this guide helpful?
Stuck on an application?

Your Partner Relationship Manager and our support team can help you finish it.

Contact support
← Back to Merchants guidesAll guides
© 2026 Constellation Payments. CSIPay is operated by Constellation Payments.
API Documentation