Build your own multi-step vendor application form with conditions, per-plan questions and document uploads.
Available Updated Oct 19, 2026Version 1.0.0Multi-Vendor 4.17.2 – 4.21.x No core file edits
Built for
Vendor Onboarding & Registration Builder: overview1 of 14
What it does
For marketplaces that need to know who they let in. Multi-Vendor asks applicants only for the seller profile fields: no documents, no steps, no follow-up questions. This add-on adds your own sections and fields to the core application form: text, text area, drop-down, multiple choice, checkbox, date and file upload, with required rules, formats, length limits and conditions. Questions can depend on the vendor plan the applicant chooses. For Multi-Vendor 4.17.2 to 4.21.
How it works
Build the form under Vendors, Vendor applications: add sections, which become steps, and fields with their rules. Applicants fill in the core account fields, click Next through your steps with a progress bar, upload documents and submit. The core creates the vendor as usual; the answers and files are stored with it. Open the vendor to read them on the Application tab, download documents, edit answers and approve or disapprove with the core buttons. Optional: answers prefill our Vendor Storefront Pro profile.
Features
Form builder with sections as steps and a progress bar, or a single page
Field types: text, text area, drop-down list, multiple choice, checkbox, date and file upload
Required fields, formats (e-mail, web address, phone, number), length limits and valid options, checked in the browser and on the server
Conditional fields: show a field only if another field has a value
Questions per vendor plan: the applicant chooses a plan and sees its questions
Document uploads with file types, size and count limits, content check and protected storage
Application tab on the vendor page with all answers and documents, editable by administrators
Applications list with status tabs, search, missing documents and CSV export
E-mail with all answers for your team and a copy for the applicant
Automatic deletion of disapproved applications' data after a set number of days
Optional prefill of the Vendor Storefront Pro profile
Full page cache safe on Multi-Vendor 4.21
What you get
Package
kv_vendor_registration_builder-1.0.0.zip, installed through Add-ons → Manage add-ons
Updates & support
12 months included. Download new versions from your account and install them in Add-ons → Manage add-ons or the Upgrade Center.
License
1 production installation. Staging, dev and localhost are free and unlimited. The add-on keeps working after the update period ends. How licensing works
Compatibility
We list only the builds we install and test on. “Tested” means the full test plan was run on that build; “Supported” means the build is inside the supported range and uses the same hooks.
CS-Cart version and edition compatibility
CS-Cart version
CS-Cart
CS-Cart Ultimate
Multi-Vendor
Multi-Vendor Ultimate
4.22 and later
Not available
Not available
Testing next
Testing next
4.21.2
Not available
Not available
Supported
Supported
4.20.x
Not available
Not available
Supported
Supported
4.19.x
Not available
Not available
Supported
Supported
4.18.x
Not available
Not available
Supported
Supported
4.17.2
Not available
Not available
Tested
Supported
Before 4.17.2
Not available
Not available
Not supported
Not supported
Last tested build: Multi-Vendor 4.17.2, Oct 19, 2026Tested on: Multi-Vendor 4.17.2
Requirements
Platform
CS-Cart Multi-Vendor 4.17.2 – 4.21.x. On CS-Cart (without Multi-Vendor) the installation is refused
PHP
PHP 7.2.5 – 8.3
Requirement
Settings → Vendors → Allow vendors to apply for an account must be on (it is the page the add-on extends)
Requirement
Optional: the core Vendor plans add-on (per-plan questions) and our Vendor Storefront Pro (profile prefill)
Core changes
None. Hooks and template overrides only
1.0.0
Oct 19, 2026
Latest
Added 11
Vendor application form builder: sections (steps) and fields (text, text area, drop-down list, multiple choice, checkbox, date, file upload) with labels, help texts, placeholders and options per language.
Steps with Back/Next and a progress bar on the core "Apply for a vendor account" page, or a single page.
Validation rules: required, formats, length limits, valid options; checked in the browser and on the server.
Conditional fields ("show if field X equals value") and sections/fields per vendor plan.
Document uploads with file types, size and count limits, content check and protected storage.
Application tab on the vendor page with answers and documents; administrators can edit answers and manage files.
Vendors > Vendor applications list with status tabs, search, missing documents and CSV export.
E-mail with all answers for the administrators and a copy for the applicant (event "Vendor application with answers").
Privacy retention for disapproved applications, manual deletion and cleanup by cron.
Optional prefill of the Vendor Storefront Pro profile draft from mapped answers.
Domain-bound license check and self-healing upgrades.
Tested on Multi-Vendor 4.17.2. First release.
How is this different from the seller profile fields of Multi-Vendor?
The core seller profile fields are one flat list with a few field types. They cannot take files, cannot be split into steps, cannot depend on another answer or on the chosen vendor plan, and every field also appears in the vendor's profile. This add-on adds a separate application form on top of them: steps, conditions, per-plan questions, document uploads, an Application tab for your review, a CSV export and e-mails with all answers. The core fields stay as they are (step 1).
Do I have to change how I approve vendors?
No. New vendors are created by the core as before, and you approve or disapprove them with the core buttons and e-mails. The add-on only adds the answers and documents to the vendor page.
Where are the documents stored? Are they safe?
In var/custom_files/kv_vendor_registration_builder/, under random file names. This folder is not reachable from the web; files are only sent through the admin panel to administrators with the "View vendor applications" privilege. The add-on accepts only the file types you allow, never scripts or web pages, and checks that the content of PDF, image and Office files matches their type.
What happens to the answers when I disapprove an application?
They stay for the number of days set in Settings → Privacy (90 by default), then the answers and documents are deleted automatically. You can delete them at once on the Application tab, and deleting the vendor deletes them too.
Can vendors see or change their answers?
Not in 1.0.0. Answers are for your review; administrators can edit them on the vendor page.
Does the form work without vendor plans?
Yes. Plan filters are only offered when the core Vendor plans add-on is active; without it every applicant sees every active field.
Does it work with the full page cache of CS-Cart 4.21?
Yes. The application page is never served from the page cache, and the add-on prints nothing visitor-specific on cached pages.
Can I use it on CS-Cart (without Multi-Vendor)?
No. The add-on extends the vendor application of Multi-Vendor, so CS-Cart refuses to install it on other editions.
What happens if the license lapses?
Without a valid license (no key after the 14-day start period, an invalid or revoked key, a domain the license does not cover, or no successful check for 14 days), the custom fields and steps disappear from the vendor application form and new applications use only the core fields. Answers and documents already received stay on the vendor pages, in the applications list and in the CSV export, and approving or disapproving vendors works as before. Once the license is valid again, everything is back.
The admin panel shows a license notice.
Open Add-ons → Manage add-ons → Vendor Onboarding & Registration Builder: the License card at the top says what is wrong: no key, a key for another add-on, a revoked license, or a domain that the license does not cover. Fix it on the License tab and click Check now. See License.
Does the add-on work on my staging copy?
Yes. Subdomains of your licensed domain (for example staging.example.com) and local development hosts (localhost, private IP addresses, .local, .test) are covered by the same license.
What happens if your license server is down?
Nothing changes for 14 days: the add-on keeps working and retries every hour. Only if no check succeeds for 14 days is it switched off until the next successful check.
Does the license check slow down my storefront or checkout?
No. The check runs only in the admin panel or from cron, at most once a day, never while visitors browse, apply or check out.
Vendor Storefront ProGive every vendor a real shop page with a banner, story, policies, business hours, social links and featured products, on every Multi-Vendor plan.
$79
+
Commission Invoices & Vendor StatementsMonthly commission invoices for every vendor, built from core accounting, with numbering, tax, credit notes, PDF and e-mail.
$129
Also from Kavio Labs
Available now and coming next, tested on the same CS-Cart builds.
