SellstampPayment links
A link, an invoice or a QR.
A sale without a storefront.
Four ways to put a payable thing in front of somebody who is not browsing your store — pasted into a message, embedded on your own site, approved by a purchasing department, or scanned off a table. All four end at the same checkout.
Buy link
yourstore.com/buy/plugin ?coupon=BLACKFRIDAY &aff=nikola &qty=3 &variant=pro
No row, no slug table, no expiry. The coupon and the affiliate reach the order through the paths that already write them.
Buy links
One screen that writes one string. You pick a product, optionally an option, a quantity, a coupon and an affiliate, and you copy a URL that arrives at checkout already filled in.
- It is a URL, not a row
- Nothing is stored when you build one. Everything the link means lives in the query string and is resolved fresh on every click against the live product, the live coupon and the live affiliate — which is why it goes on working in a newsletter delivered once and read for years.
- What it can carry
- A variant, a quantity, a coupon code and an affiliate's referral code. The builder in your dashboard picks each from what your store actually has and writes the string for you. The prefill runs the same coupon engine the checkout runs, so a code the link keeps is a code the till would have honoured.
- A stale parameter is dropped, never refused
- A coupon that expired, was exhausted, or fails its minimum order arrives empty; a quantity past the field's limit is clamped to it; a variant or affiliate that no longer exists is skipped and the rest of the link still works. A customer who followed your link did nothing wrong, and a link that can fail closed has negative value.
- The trade, stated
- Because there is no row, there is nothing to revoke and nothing to count. A link you have already sent cannot be killed from a screen you have since forgotten — which is the point, and also the cost.
Or put the buy form on your own site
One route on your storefront is framable, and only by the origins you list. Your audience buys where it already is instead of being sent somewhere else and losing part of itself on the way.
One framable route
Exactly one path answers with frame permission, scoped to the origins you name. Every other page in the product — the dashboard, the order pages, the payment pages — still refuses framing outright.
A message, not a navigation
The embedded form talks back to your page rather than trying to navigate it, so your site decides what happens when a purchase completes.
The same buy form
It is the storefront's own form, not a second copy of it. Prices, options, tiers and coupons behave identically because they are the same code — minus the affiliate code, which a browser will not carry into a frame.
Quotes, proformas and net terms
A company's purchasing process is: somebody asks for a quote, somebody else approves it, a PO is raised against it, and only then may anyone pay. A store that cannot produce one is not missing a feature for that buyer — it is unbuyable.
- A quote is a real document
- Its own table, its own per-shop counter, its own series. Abandoning nine out of ten cannot leave a hole in your VAT sequence, because nothing about a quote can reach that sequence.
- The snapshot is the contract
- Acceptance writes the order from what the quote froze, never from today's catalogue. A price rise, a rename or an ended sale between sending and accepting does not reach the buyer — that is what “valid 30 days” has to mean.
- Validity is a date, not a status
- Expired is a comparison against now, made by every screen that asks. No sweep has to run for a quote to stop being live.
- The buyer's own paperwork
- Company name, registration and VAT number (validated against VIES), and their purchase-order number carried through onto the order and the invoice.
- Proformas and net terms
- A proforma has its own series for the same reason a quote does. Net terms are an approval you grant one buyer's email address: a checkout asking for terms without one is refused with the goods still in the shop, and the invoice is issued at delivery rather than at payment.
The customer opens the quote from their email through a per-quote token, accepts or declines it there, and pays an ordinary order. There is no account to create and no portal to sign into — the link is the only proof there is, and a wrong one is a 404 rather than a message confirming the quote exists.
And in person
A market stall sells the same thing the store does. A POS link puts a code on the table and the customer pays on their own phone — no reader, no terminal SDK, no card data anywhere near you.
This one is a credential
Unlike a buy link, a POS link is a row: hashed at rest, expiring, revocable, and single-use if you want it. It authorises an in-person sale, and a credential you cannot revoke is a liability.
A basket, not one item
The counter can build up several lines and take one payment for them, using the same buy form the storefront uses.
Or a QR into a bank app
IPS QR and EPC QR are built for exactly this: the customer's own banking app reads the code and pre-fills a transfer into your account.
Knowing where a sale came from
Put your own UTM tags on a link and the landing writes them down, with the click’s id in a first-party cookie; at checkout that id is resolved against this shop and frozen onto the order. An id from another store, an expired one, or one somebody typed resolves to nothing and the sale is simply unattributed. What is stored is what you wrote into your own link — the address, the user agent and the referrer are never looked at.
What this does not do
- No link shortener and no per-link click dashboard. A buy link has no row, so there is nothing to count clicks against; campaign links are the surface that does have one.
- No hosted “payment page” with a price you type in. A link always points at a product in your catalogue, so the price, the tax category and the fulfilment are the ones you already set.
- No affiliate attribution through the embed. A referral cookie is third-party inside a frame and browsers block it, so an embedded buy button carries a coupon and a variant but not a referral.
Open a store and try it.
Everything on this page is in the product today. Connect a provider in test mode and put a real order through it before you decide.