Your customer's AI assistant already knows where they're going on holiday, how many people are coming, and what dates they're free. Let it pre-fill your checkout today.
What "agentic commerce" means right now
There are many things you can do to meet agents where they are. The simplest, and the one this post is about, is to let an agent read your site and redirect the shopper to a checkout with a fully filled basket. At the more ambitious end, an agent transacts on the user's behalf using delegated payment credentials and a machine-to-machine commerce protocol. The protocol end is being built by the major wallet, network, and AI players, but adoption is thin and none of it is something a SaaS platform needs to ship this quarter.
Hosted checkouts still convert much better than in-chat ones. Early data from Walmart suggests that purchases completed inside ChatGPT converted three times worse than click-throughs to their own site Search Engine Land. Your own checkout is the place to land the shopper.
What you can do today is make your checkout something an agent can hand off to, so any agent that lands on your site can redirect the shopper to a checkout with a fully filled basket.
Filling the basket: the minimum viable agentic checkout
A pre-fill link is a checkout URL that encodes everything the agent has already figured out: products, quantities, date, traveler counts, name, email. The customer arrives on a checkout that is ready to pay. They review and confirm.
Here is a live example. We built a ticketing site for a fictional rollercoaster park, running on Rootline, and pointed an LLM at it.
The agent read availability, picked the cheapest mix for a family of three, chose an open date, and pre-filled name and email.
What to implement on your side
You need four things.
A deterministic checkout URL, documented on the checkout page itself. Define a URL where every cart-relevant decision can be expressed as a query parameter. Keep it human-readable so an LLM can construct it from your own documentation. The format spec belongs on the checkout page, not on a separate developer docs site. Most agents that crawl your site to plan a purchase will land on the checkout, read what is there, and construct the link from that.
The pattern we use on the demo site:https://rootline-coasters.com/checkout?item=<ticket_id>:<qty>&date=<YYYY-MM-DD>[&item=...][&ref=...][&name=...][&email=...].
A shorthand form is also accepted:?adult=2&child=1&date=2026-06-15.
A complete example:?item=adult:2&item=child:1&date=2026-06-15&name=Jane%20Doe&email=jane%40example.com&ref=concierge-bot.Public availability and pricing the agent can read. The agent can only pre-fill what it can see. Publish a day-by-day availability table and a pricing table as plain HTML on a crawlable page. No JavaScript-only rendering, no auth wall. If the data is locked behind a SPA bundle, most agents will not get to it.
Server-side validation of every parameter. Treat the query string as untrusted input. Reject closed dates, unknown item IDs, and impossible quantities. For optional fields like name, email, or ref, drop the value silently when it fails validation rather than erroring out. You don't want to lose a customer because a malformed ref tag killed the whole link.
Low-friction payment on arrival. The whole point is that the customer lands on a screen where the only remaining action is to pay. Apple Pay and Google Pay wallet buttons on the checkout collapse that to a single tap, or let customers save their card for next time. If you are already on Rootline, both come with the standard integration.
When it falls back
We found it works best when thinking mode is enabled, which tends to require a paid tier, and when your site is well indexed in search engines. Our demo site needs the full link pasted because it is not indexed yet. Avoid prompting the agent with language like "buy a ticket," the AI will refuse. Customers also do not expect ChatGPT to actually buy a ticket on their behalf, so their natural keywords are "where to buy" instead. When it does not work, the agent falls back to linking the main website or pricing page.
What comes next
Pre-fill links work today and they are cheap to ship. The same structured parameters you expose now are most of what the emerging agent payment protocols will eventually ask you to expose in JSON, so this work compounds rather than gets thrown away. Adding Apple Pay and Google Pay wallet buttons to the checkout takes the experience from "pre-filled" to one-tap. When the whole flow lines up, it feels like magic.
Want to learn more?
Explore Rootline in more detail or speak to our team to see how it can support your platform.
