01
The five fields used in the timeline
Applies to marketplace onlyown storefronthybrid
Events in this field are often described with a single general term — a protocol is "launched", a surface "supports" checkout, a program "goes live". The timeline records each event in five separate fields instead, because each field answers a different question and is supported by a different kind of evidence.
| Field | Information recorded | Common source |
|---|---|---|
| Announcement | A party stated an intention publicly, on a date | A dated blog post or press release |
| Documentation | An interface is described in enough detail to build against | A versioned specification or API reference |
| Merchant access | Which merchants can reach the path, and how | Eligibility criteria, onboarding steps, an application process |
| Testing availability | Whether behavior can be verified before committing | A sandbox, conformance suite, or example implementation |
| Documented production use | A completed transaction through this path, on the public record | A first-party report, or a merchant’s own records |
The fields are kept separate because one does not imply the next. A specification does not by itself provide access. An access path does not by itself provide a test environment. A test environment does not itself document production use. Recording each answer in its own field, with its own source, keeps those distinctions visible when an entry is read months later.
Separate does not mean exclusive. Most events fill more than one field at once: a specification release is both an announcement and documentation, a policy amendment is an announcement that changes merchant access, and a foundation launch is an announcement that carries governance information. The fields record what an event establishes, and a single event can establish several things.
02
The timeline at a glance
Applies to marketplace onlyown storefronthybrid
These are the dated entries in the current record, in order. Two of the sources are continuously updated documentation with no publication date of their own; they appear at the end with that status noted, and the date that matters for them is the date you read them.
| Date | Event | Fields it fills |
|---|---|---|
| September 29, 2025 | The Agentic Commerce Protocol specification is first published, in beta, maintained by OpenAI and Stripe.1 | Announcement, documentation |
| February 20, 2026 | An amended eBay User Agreement takes effect, allowing automated access and purchasing only with eBay’s prior express permission.3 | Announcement, and a change to merchant access |
| April 8, 2026 | The Universal Commerce Protocol specification is published as a dated snapshot, with the date in the document’s URL.4 | Announcement, documentation |
| April 17, 2026 | The Agentic Commerce Protocol publishes a stable snapshot, with unreleased development tracked separately.1 | Documentation |
| July 14, 2026 | The Linux Foundation announces the operational launch of the x402 Foundation, with roughly forty founding organizations across three membership tiers.2 | Announcement, governance |
| Continuously updated | OpenAI’s onboarding documentation for its direct product-feed path, with onboarding limited to approved partners by application.5 | Documentation, merchant access |
| Continuously updated | Shopify’s help documentation for agentic storefronts, with eligible stores enabled by the platform and some channels in early access.6 | Documentation, merchant access |
Testing availability and documented production use do not appear in the right-hand column for any entry, because the current cited sources do not fill those fields. The rest of this lesson explains how the entries are maintained and how to read them against your own channels.
03
How entries are recorded
Applies to marketplace onlyown storefronthybrid
The timeline is kept as a data file checked into the repository, not as prose. Every entry records its date, its governing party, the version it describes, and its source. Each of the five fields is either filled in or intentionally left empty.
This structure keeps claims tied to sources. To record that a protocol has a test environment, the maintainer fills in the testing field and attaches the source that documents it, so a reviewer can check one against the other. An empty field means the current cited sources do not provide that information.
Some sources make version identification easy. One specification includes its snapshot date in the document’s URL, so readers can tell exactly which version they are looking at and compare it with the version they built against earlier.4
04
Information currently included
Applies to marketplace onlyown storefronthybrid
The entries recorded so far contain three main kinds of information. These are not separate buckets — as the table above shows, a single entry usually contributes more than one kind, so the groupings below describe what the sources contain, not a sorting of entries.
Specification documents. Dated, versioned snapshots have been published, and they describe interfaces in enough technical detail to build against.1 These fill the documentation field for their entries.
Governance information. Some entries record who stewards a specification and under what structure. For example, a payments protocol moved to a foundation under neutral stewardship in July 2026, with roughly forty founding organizations across three membership tiers.2 A governance entry of this kind documents membership and stewardship arrangements. Implementation and deployment are separate facts, recorded in their own fields when a source documents them.
Production use. The documented-production-use field is currently empty for every entry: the cited sources do not include a documented production transaction for a specific merchant’s goods. The published materials from the operating parties do not include per-merchant transaction figures, and no independent source in the registry provides them. As with any empty field, this records what the sources contain, not whether the underlying activity is or is not occurring.
05
Access rules and policy changes
Applies to marketplace onlyown storefronthybrid
The timeline records policy changes as ordinary entries, not as a separate category. A policy entry is itself an announcement with a date and a source; what distinguishes it is which field it changes — usually merchant access, and usually for paths that already existed. Access rules move in both directions, and the changes often arrive as amendments to governing documents rather than as press releases. One documented example: the February 20, 2026 amendment restricts buy-for-me agents, LLM-driven bots, and end-to-end automated ordering on a major marketplace unless the operator has prior express permission.3
Including both kinds of entry gives a fuller picture when you read the record against your own channels. A launch entry may describe a path you could apply for; a policy entry may describe a rule that already applies to a venue where your inventory is listed. For a seller on that marketplace, the February 2026 entry describes a current, in-force condition, which is why policy entries carry the same date-and-source treatment as launches.
06
Gaps in the public record
Applies to marketplace onlyown storefronthybrid
The timeline is built from published, dated sources, and some kinds of events do not generate one. A discontinued pilot, a program that stops accepting applications, or an integration that no longer appears in a partner list often ends without a dated public document.
Because of this, the timeline records publicized starts more completely than quiet stops. Where a change is visible only through a page ceasing to exist, the course records nothing rather than inferring an event without a source. Readers should treat the ledger as a record of what has been published, with the understanding that program closures may exist that no current source documents.
07
Using the timeline as a merchant
Applies to marketplace onlyown storefronthybrid
For most merchants, the most useful field on any entry is merchant access, because it is the field that can describe an available action. A practical way to read the timeline is to check that field first and note what, if anything, it makes available to you.
- Take the three most recent entries and read each one’s merchant-access field.
- For each, note the concrete step the sources describe — an application, a feed field, a settings check, a policy read — or note that the sources describe no path available to you. Both are useful notes to keep.
- Note which steps you could undo within a day, since easily reversed steps can be taken while other fields are still empty.
- Revisit the notes when the record next changes.
Applied to the Meridian camera, the access field gives different answers for different entry types:
| Entry type | Access for this seller | Available action | Publicly documented production use |
|---|---|---|---|
| Feed onboarding for a named assistant | By application, approved partners only | Submit an application and wait | Not in current sources |
| Storefront platform default participation | Enabled by the platform for eligible stores | Check whether it is on, and time a removal | Not in current sources |
| Marketplace restriction on automated ordering | Applies to sellers on that venue | Read the clause before assuming permission | Not in current sources |
| Payments specification under neutral governance | Not a merchant-facing path | None described | Not in current sources |
Two rows come directly from their sources. Onboarding for one feed program is documented as limited to approved partners and entered by application, so access for a non-partner merchant currently means applying and waiting.5 Separately, one platform enables eligible stores by its own decision, so participation can already be active without the merchant having taken any step6 — which is why checking your current settings appears in the table as an available action.
08
Current summary
Applies to marketplace onlyown storefronthybrid
The timeline currently spans September 2025 through July 2026, plus two continuously updated documentation sources. Its entries include: specification snapshots with dates and versions; a governance launch with named memberships and stewardship tiers; access paths with documented eligibility criteria and application processes; a platform that enables participation for eligible stores by default; and a marketplace policy, in force since February 20, 2026, restricting automated ordering without prior express permission. Many entries fill several fields at once, which is why the record is read by field rather than by entry.
Public information remains incomplete in two areas. The cited sources do not include documented production transactions or per-merchant usage figures, and events that end without an announcement — closed pilots, paused programs — may not appear at all.
When reading any entry, an empty field means the current cited sources do not provide that information. Filled fields carry a date and a source, so they can be re-checked when either changes.
09
Practice
Exercise
Read the ledger by field
- Open the course research page and read the three most recent milestone entries.
- For each, note which of the five fields the sources fill in and which are empty.
- Note any step the merchant-access field describes for you, or record that none is described.
Check yourself
A protocol publishes a dated specification snapshot. Which fields does that fill in?
Announcement and documentation. Merchant access, testing availability, and documented production use are separate fields, each requiring its own source.
A foundation launch names forty founding organizations. Which field does that fill?
Governance information within the announcement: it documents who has agreed to steward the specification and under what structure. Implementation and deployment are separate facts, recorded only when a source documents them.
What does an empty documented-production-use field mean?
That the current cited sources do not include a documented production transaction. It does not indicate whether such transactions are or are not occurring — only that no source in the registry documents one.
Progress is saved in this browser only. No account, nothing sent anywhere.
10
Common questions
Is a specification being versioned a sign of maturity?
Versioning lets you pin the exact snapshot you built against and detect changes later, which is practically useful. It is separate from the access, testing, and production-use fields, which have their own sources.
How often does this timeline change?
Irregularly, with clusters of entries around vendor events. Each entry carries its own date, so a period with few entries is visible in the record as exactly that.
Should I act on an announcement before documentation exists?
The sources for an announcement-only entry describe an intention rather than an interface, so any building done against it may need rework when documentation is published. Steps that pay off regardless — such as improving your own product records — do not depend on the entry at all.
Why not include analyst forecasts or market-size figures?
The ledger records dated events from first-party sources: what was published, by whom, on what date. Forecasts and market estimates are a different kind of material and are outside its scope.
11
Research and sources
Rules and platform policies change. These primary sources were reviewed on ; confirm the current position for your jurisdiction and account before acting.
Claim evidence
- A dated specification snapshot records that an interface was published in a stated version on a stated day; it carries no statement that any party implemented it or that a merchant can reach it.
- technical requirement. Supported by Agentic Commerce Protocol repository and specification .
- A foundation launch announcement establishes the governance arrangement and stated scope of a project and does not establish merchant adoption or production interoperability.
- current external fact. Supported by Operational launch of the x402 Foundation .
- A dated agreement amendment restricting automated purchasing belongs on the same record as capability launches, because access to a venue can narrow on a date as readily as it can widen.
- current external fact. Supported by eBay User Agreement .
- The operational launch of a payments foundation under neutral governance carries a July 2026 date and names around forty founding organizations across three membership tiers, settling who has agreed to steward a specification and settling nothing about what any of them has put into production.
- current external fact. Supported by Operational launch of the x402 Foundation .
- One specification publishes its snapshot date inside the web address of the document, so which version a reader has in front of them is legible before the page has even rendered.
- technical requirement. Supported by Universal Commerce Protocol official specification .
- Where documented onboarding is open to approved partners and entered through an application form, the accessibility question for that entry resolves to a queue rather than to a yes.
- current external fact. Supported by Agentic Commerce: Get started .
- An entry where a platform switches eligible stores on by its own decision is one of the few that answers the accessibility question affirmatively with no merchant action at all, which is also what makes it easy to read past.
- current external fact. Supported by Shopify agentic storefronts .
- Agentic Commerce Protocol repository and specification Agentic Commerce Protocol · Tier A · beta · 2026-04-17 stable snapshot; unreleased development tracked separately
ACP checkout, cart, feed, order, authentication, and extension models. Limit: A beta specification maintained by OpenAI and Stripe does not prove platform adoption, merchant access, conformance, or interoperability.
- Operational launch of the x402 Foundation Linux Foundation · Tier D · official launch announcement · announcement dated 2026-07-14
Linux Foundation governance and stated scope for the x402 Foundation. Limit: Establishes the foundation’s operational launch and stated governance scope, not merchant adoption, production interoperability, settlement finality, or liability allocation.
- eBay User Agreement eBay · Tier A · current policy · live agreement
Automated access and purchasing on eBay. Limit: Applies to eBay and allows automated access only with eBay’s prior express permission.
- Universal Commerce Protocol official specification Google · Tier A · published specification · 2026-04-08
UCP discovery, capability negotiation, shopping, fulfillment, and payment-handler models. Limit: The specification states interfaces and normative language; it does not prove that a particular merchant or surface implements them.
- Agentic Commerce: Get started OpenAI · Tier A · current documentation · unversioned live documentation
OpenAI direct product-feed onboarding and delivery models. Limit: Describes OpenAI’s current direct-feed path. It does not establish eligibility, surfacing, placement, traffic, or sales for a merchant.
- Shopify agentic storefronts Shopify · Tier A · current help documentation · live documentation
Shopify agentic-storefront eligibility, default activation, channel behavior, and checkout posture. Limit: Documents Shopify stores only. Some channels are early access and not available to every store.