Vendor Onboarding Guide

Creating your Mainstreamed Marketplace account is quick and easy. Follow these steps to get started!

• Open your web browser and go to www.mainstreamedmarketplace.com.
• Click "Sign up" in the top-right corner of the page.
• On the Sign-Up screen, click the "User type" dropdown and select "Provider"
• Fill in your email, first name, last name, and how you’d like your name to be displayed on your store.
• Create a strong password (at least 8 characters, mix of letters and numbers).
• Click the box next to "I accept the Terms of Service and the Privacy Policy." Click the links to read each document before accepting.
• Click the "Sign up" button.
• Check your email inbox for a verification email from Mainstreamed Marketplace. Click the link inside to confirm your account.

Once verified, log back in at mainstreamedmarketplace.com and you're ready to set up your store!

• Log in to your Mainstreamed Marketplace account.
• Click your profile icon with your initials in the top-right corner.
• Select “Profile Settings" from the dropdown menu.
• Upload a profile photo (recommended: 400×400px, square, JPG or PNG, under 2MB). Tip: use a clear headshot or your business logo!
• Fill in your first name, last name, and display name. The display name is what customers will see when they go to your page – so you may want to put your business name here!
• Complete your bio. This is where you can share your story! A complete, professional profile builds buyer trust and helps customers learn who you are and what makes your business special. This is also where you should set your store policies for returns. Clearly state whether you accept returns, within what timeframe, and in what condition. Any accessibility related information may also be relevant here.
• Make sure to click “Save changes” when you are done.

If you are selling products through your Mainstreamed Marketplace site, you'll need to receive payments through Stripe — a secure, industry-leading payment platform. You must connect your Stripe account to your profile to perform transactions. This is required before your listings can go live and accept orders. (If you're only using Mainstreamed Marketplace for discovery and not processing sales through the platform, you can skip this step.)

From your profile icon in the top right corner, click "Account Settings." Click "Stripe Account" on the bottom left. Follow the prompts to create a new Stripe account or connect an existing one. If you're creating a Stripe account for the first time, you'll need to add your bank details along with information about your business. This is how you'll receive payments and track every transaction that comes through your store.

Important: Mainstreamed Marketplace does not process transactions on your behalf. Every sale on your store runs through your own Stripe account, which means you are the merchant of record. In practice, this means:

You handle returns and disputes directly through Stripe. You're responsible for remitting any sales tax you collect. Mainstreamed Marketplace simply gives you the tools to manage all of this more easily — the transactions themselves are yours. Make sure to choose a statement descriptor that accurately describes your business name. This will be what appears on your customers' bank or credit card statements. Review Stripe's Terms of Service and click "Agree & Submit." Make sure that you see "Your Stripe Account is up to date!" on your Stripe Account tab before proceeding. Funds from your sales will automatically be transferred to your bank account on Stripe's standard payout schedule (typically 2–7 business days after a completed order).

Important Note: Stripe is a third-party service. Mainstreamed Marketplace does not store your bank details — all financial information is securely handled by Stripe. If you have questions about Stripe's process, visit stripe.com/support.

Mainstreamed Marketplace does not provide legal or tax advice. Vendors are responsible for understanding and complying with all applicable tax laws and registration requirements related to their business.

All transactions will be processed using the vendor’s connected Stripe account, meaning the vendor is the merchant of record for all transactions. As a result, vendors are responsible for understanding and complying with all applicable tax laws, registration requirements, reporting obligations, and tax filings related to their business.

Your connected Stripe account must have:

• A valid US head-office state configured
• An active sales tax registration in that state
• Product Tax Codes

If tax readiness requirements are not completed, customers will be unable to complete purchases from your store. Listings will use product tax codes to help Stripe calculate taxes correctly. If a product tax code is missing, Stripe will automatically fall back to a default tax code. All of these requirements can be set up on the Sales tax tab of your vendor dashboard.

Vendors are responsible for:

• Sales tax registration
• Tax compliance
• Tax filings and remittance
• Maintaining accurate tax information in Stripe

Requirements vary depending on your business location, where you sell, product type, and sales activity. If you are unsure about your obligations, consult a CPA, tax professional, or your state’s Department of Revenue before launching your store.

If you are selling physical products that need to be shipped to customers, you'll need to connect a Shippo account. Mainstreamed Marketplace offers integration with Shippo to make it easy to calculate shipping rates, generate labels, and share tracking information with buyers, all in one place. (If you offer local pickup only, or you're using Mainstreamed Marketplace for discovery rather than fulfilling orders through the platform, you can skip this step.)

From your profile icon in the top right corner, click "Account Settings." Click "Shipping" (or "Shippo Account") on the left-hand menu. Follow the prompts to create a new Shippo account or connect an existing one. Enter your ship-from address. This is the return address that will print on your labels. Choose your preferred carriers and services (e.g., USPS, UPS, FedEx), if prompted. Make sure you see "Shippo Connected" on your Shipping tab before publishing listings that require shipping.

Important: This is your own Shippo account, not Mainstreamed Marketplace's. Mainstreamed Marketplace is simply connecting it to your dashboard for convenience — we do not process or mark up any shipping charges. Any costs for printing labels or shipping packages are billed directly between you and Shippo, separate from your Mainstreamed Marketplace fees. If you have questions about label pricing or carrier issues, visit goshippo.com/support.

Click "Post a new listing" in the top-right corner. Choose the category that best fits your item or service. Add a clear, descriptive title and detailed description — mention condition, materials, dimensions, and anything a buyer would want to know. Upload photos (recommended: multiple angles, good lighting, not too busy of a background). Add a detailed photo description — this makes your listing accessible to buyers using screen readers and can also help your listing surface in search results. Set your price. If you are selling products through Mainstreamed Marketplace, select the applicable product tax code so Stripe can calculate sales tax correctly, and enter shipping details (package weight and dimensions) so Shippo can calculate accurate rates at checkout. Set your stock/availability if applicable. Include your return policy directly in the listing description, even if you've already stated it on your profile. Buyers often check the listing itself rather than your profile page, so restating it here (timeframe, condition requirements, who covers return shipping) helps avoid disputes later. Review your listing preview, then click "Publish."

Once published, your listing will be searchable and visible to buyers. If you're selling through the platform, it will also be available for purchase — as long as your Stripe and tax setup are complete.

This section applies if you're selling products. If you're using the platform for discovery only, you can skip this step.

• Go to your "Sales" or "Orders" tab from your profile menu to see all incoming orders.
• When a new order comes in, you'll receive an email notification. Review the order details and confirm you can fulfill it.
• Once confirmed, purchase and print your shipping label directly through your connected Shippo account (accessible from the order page).
• Once you have fulfilled and shipped the order, mark the order as such.
• Once the buyer receives and confirms the item (or after the standard confirmation window closes), funds are released to your Stripe balance for payout.
• If an issue arises (damaged item, return request, etc.), refer to the return policy you set in your profile and communicate with the buyer through your Mainstreamed Marketplace inbox.

Do I have to sell products through Mainstreamed Marketplace, or can I just use it for discovery?

• You can use Mainstreamed Marketplace purely for discovery — showcasing your business and listings without processing sales through the platform. If you do want to sell and accept payments here, you'll need to connect Stripe and, if you're shipping physical goods, Shippo.

How long does it take to get paid?

• Once an order is marked complete, funds are released to your connected Stripe account and paid out on Stripe's standard schedule (typically 2–7 business days).

Does Mainstreamed Marketplace process my payments or hold my money?

• No. All transactions run through your own Stripe account, and you are the merchant of record. Mainstreamed Marketplace does not process, hold, or mark up any payments.

Do I need a Shippo account to sell?

• Yes, if you're shipping physical goods. Shippo is how labels are generated and tracking is shared with buyers. Note that this is your own Shippo account — shipping and label costs are billed directly between you and Shippo.

Who is responsible for collecting and remitting sales tax?

• Sellers are. Mainstreamed Marketplace does not provide tax advice; nor do they collect and remit on the seller's behalf. Sellers are responsible for sales tax registration, compliance, collection, and remittance related to your business. All product transactions are performed from seller stripe accounts.

What if a buyer wants a refund or return?

• Refunds and returns are handled according to the return policy you set on your profile and in your listings. Communicate with the buyer through your Mainstreamed Marketplace inbox, and process any refund through Stripe.

Where should I state my return policy?

• Both on your profile and directly in each listing description, so buyers can see it no matter how they find your store.

Who do I contact if something goes wrong?

• Platform issues (listings, account, dashboard): Mainstreamed Marketplace support - info@mainstreamedmarketplace.com
• Payment or payout issues: Stripe support
• Shipping or label issues: Shippo support