Public record · MIT licensed
The SERP event registry.
A dated, sourced, confidence-tagged public record of AI model releases, search feature changes, confirmed algorithm updates, and observed SERP volatility, from November 2022 onward.
Coverage runs across the AI answer surfaces, including ChatGPT, Perplexity, the Gemini app, AI Overviews and AI Mode, alongside the classic Google SERP and Discover. The repository is the source of truth; this page renders it.
The instrument
The attribution ladder.
Every row carries one of four tiers, and the tier describes the event and its date together. A well known event with a poorly attested date does not get the top tier. Rows move down the ladder as readily as up, and corroboration from a volatility sensor is recorded on the row without moving the tier.
- 1
Vendor confirmed
vendor_confirmed
The vendor stated the event and the date on its own property, and the date can be read off that property today.
- 2
Vendor announced
vendor_announced
The vendor announced the event, but the rollout window is uncertain, or the date was taken from contemporaneous reporting rather than a vendor dateline.
- 3
Community inferred
community_inferred
No vendor statement exists, and multiple independent observers converge on the event and its approximate date.
- 4
Hypothesis
hypothesis
We suspect the event happened and the row says so. It stays at this tier until a vendor statement or independent convergence moves it.
The record
Every event in the registry, newest first.
All 26 rows are on this page. Open a row for the full description and the primary sources it rests on.
| Date | Type | Surfaces | Event | Attribution |
|---|---|---|---|---|
| Model release |
| OpenAI opens general availability of GPT-5.6 DetailHide detailOpenAI opened general availability of GPT-5.6 across its Sol, Terra, and Luna variants. A restricted preview had gone to roughly twenty partner organizations on 26 June 2026 while a United States government safety review was outstanding, so the model was already serving production traffic about two weeks before general access. The date recorded here comes from contemporaneous reporting rather than a dateline on the vendor page.
| Vendor announced | |
| Spam update |
| Google June 2026 spam update DetailHide detailGoogle released the June 2026 spam update, logged on the Search Status Dashboard with no country or language carve out. The dashboard recorded completion on 26 June 2026 at 10:00 US/Pacific. This is the most recent confirmed Google ranking update in the registry as of the seed date.
| Vendor confirmed | |
| Core update |
| Google May 2026 core update DetailHide detailGoogle released the May 2026 core update, logged on the Search Status Dashboard with no country or language carve out. Google estimated a rollout of up to two weeks, and the dashboard recorded completion on 2 June 2026 at 05:40 US/Pacific. It began two days after the I/O 2026 announcement that AI Mode becomes the global Search default, so ranking movement and surface composition were both in motion across the same window.
| Vendor confirmed | |
| Search feature change |
| Google makes AI Mode the global Search default at I/O 2026 DetailHide detailAt Google I/O 2026, Google announced that AI Mode becomes the default Search experience worldwide, with Gemini 3.5 Flash serving it, alongside a redesigned query box and background agents that keep researching between sessions. Google placed those agents with Google AI Pro and Ultra subscribers in the United States over the months following, so the announcement date and the date any given user met the new default are not the same. This row records the announcement date and asserts no completion date.
| Vendor announced | |
| Core update |
| Google March 2026 core update DetailHide detailGoogle released the March 2026 core update, logged on the Search Status Dashboard with no country or language carve out. Google estimated a rollout of up to two weeks, and the dashboard recorded completion on 8 April 2026 at 06:00 US/Pacific. The March 2026 spam update had finished only two days before this rollout began.
| Vendor confirmed | |
| Spam update |
| Google March 2026 spam update DetailHide detailGoogle released the March 2026 spam update, logged on the Search Status Dashboard with no country or language carve out. The dashboard recorded completion on 25 March 2026 at 07:30 US/Pacific, under a day from start to finish. It began three days before the March 2026 core update, so the two rollouts sit close enough together that they should not be read as one event.
| Vendor confirmed | |
| Model release |
| OpenAI releases GPT-5.4 with native computer use DetailHide detailOpenAI released GPT-5.4 across ChatGPT, the API, and Codex, with the model able to drive software directly and to hold roughly a million tokens of context. A smaller GPT-5.4 variant followed on 17 March 2026 and reached free tier ChatGPT users, so the model behind free tier answers changed on a later date than the flagship release did. The date recorded here comes from contemporaneous reporting rather than a dateline on the vendor page.
| Vendor announced | |
| Core update |
| Google February 2026 Discover core update DetailHide detailGoogle released what the Search Status Dashboard names the February 2026 Discover core update, scoped at release to English language users in the United States, with Google saying it would look at widening that later. The dashboard recorded a start of 5 February 2026 at 09:00 US/Pacific and completion on 27 February 2026 at 02:00 US/Pacific, so the rollout ran well past the two weeks Google estimated. It is typed core_update because that is the vendor's own name for it, but it touched Discover rather than web Search and only one country and language, so pooling it with the web core updates in this file would be an error.
| Vendor confirmed | |
| Model release |
| OpenAI releases GPT-5.2 DetailHide detailOpenAI released GPT-5.2, starting the ChatGPT rollout with paid plans while making it available in the API straight away. The release shares a start date with the December 2025 Google core update, so volatility seen in this window cannot be assigned to either event without separating the surfaces first. The date recorded here comes from contemporaneous reporting rather than a dateline on the vendor page.
| Vendor announced | |
| Core update |
| Google December 2025 core update DetailHide detailGoogle released the December 2025 core update, logged on the Search Status Dashboard with no country or language carve out. Google estimated a rollout of up to three weeks, and the dashboard recorded completion on 29 December 2025 at 11:00 US/Pacific. This rollout shares a start date with the GPT-5.2 release, which any event study over this window should treat as a confound rather than a coincidence to wave through.
| Vendor confirmed | |
| Model release |
| Google releases Gemini 3 and deploys it into Search DetailHide detailGoogle released Gemini 3 and shipped it into Search and the Gemini app on the announcement date rather than staging it behind a preview period. A frontier model landing in Search the same day it is announced is the case this registry exists to capture, because a model event and a search side answer change share one timestamp and cannot be told apart by date alone. The vendor page carries the announcement date.
| Vendor confirmed | |
| Search feature change |
| Perplexity makes Comet free worldwide DetailHide detailPerplexity dropped the subscription and waitlist gate on Comet and released it free in every market. What changed is the addressable population of the surface rather than how it answers, which is why this is a separate row from the limited launch. The date recorded here comes from contemporaneous reporting rather than a dateline on the vendor page.
| Vendor announced | |
| Spam update |
| Google August 2025 spam update DetailHide detailGoogle released the August 2025 spam update, logged on the Search Status Dashboard with no country or language carve out. The dashboard recorded completion on 22 September 2025 at 00:00 US/Pacific, putting the rollout at roughly four weeks. Google issued no separate guidance alongside it.
| Vendor confirmed | |
| Model release |
| OpenAI releases GPT-5 and makes it the ChatGPT default DetailHide detailOpenAI released GPT-5 and made it the ChatGPT default, retiring the manual model picker in favor of routing each request automatically between quicker and more deliberative variants. Which model answers a given prompt therefore changed without any user action, which matters to any measurement series that assumed a fixed model sat behind the surface. The date recorded here comes from contemporaneous reporting rather than a dateline on the vendor page.
| Vendor announced | |
| Search feature change |
| Perplexity launches Comet browser to Max subscribers and waitlist DetailHide detailPerplexity launched Comet, a browser that carries its assistant alongside whatever page is open rather than in a separate destination. Distribution was invitation gated at launch, reaching Perplexity Max subscribers and selected waitlist entrants, so the population able to reach the surface grew on a schedule Perplexity did not publish. The date recorded here comes from contemporaneous reporting rather than a dateline on the vendor page.
| Vendor announced | |
| Core update |
| Google June 2025 core update DetailHide detailGoogle released the June 2025 core update, logged on the Search Status Dashboard with no country or language carve out. Google estimated a rollout of up to three weeks, and the dashboard recorded completion on 17 July 2025 at 01:00 US/Pacific. Both the start and completion timestamps are vendor published.
| Vendor confirmed | |
| Search feature change |
| Google makes AI Mode available to all United States Search users DetailHide detailAt Google I/O 2025, Google announced that AI Mode would reach every Search user in the United States, taking it out of Search Labs, with a custom build of Gemini 2.5 serving it. Google said the tab would show up on US searches during that week, so per user availability trailed the announcement by an interval nobody published. This row records the announcement date.
| Vendor announced | |
| Model release |
| Google releases Gemini 2.5 Pro Experimental DetailHide detailGoogle released Gemini 2.5 Pro Experimental, the first model in the Gemini 2.5 family, which Google characterizes as one that works through a problem before it answers. It reached the Gemini consumer app for Advanced subscribers at announcement and later became the model serving AI Mode in Search. The vendor page carries the announcement date.
| Vendor confirmed | |
| Core update |
| Google March 2025 core update DetailHide detailGoogle released the March 2025 core update, logged on the Search Status Dashboard with no country or language carve out. Google estimated a rollout of up to two weeks, and the dashboard recorded completion on 27 March 2025 at 05:35 US/Pacific. Both the start and completion timestamps are vendor published.
| Vendor confirmed | |
| Search feature change |
| Google introduces AI Mode as a Search Labs experiment DetailHide detailGoogle introduced AI Mode, a separate tab in Search that answers conversationally and takes follow up questions, as a Search Labs experiment limited to Google One AI Premium subscribers in the United States. The same announcement put Gemini 2.0 behind AI Overviews for harder query classes. The vendor page carries the announcement date and Labs availability opened the same day.
| Vendor confirmed | |
| Search feature change |
| OpenAI launches ChatGPT search with real time web retrieval DetailHide detailOpenAI launched ChatGPT search, letting the assistant pull current pages while composing an answer and attribute the pages it drew on. Access was restricted to Plus and Team subscribers at launch and was widened to all logged in users in February 2025. This row records the initial launch; the later widening is not separately seeded.
| Vendor announced | |
| Search feature change |
| Google expands AI Overviews to more than 100 additional countries DetailHide detailGoogle widened AI Overviews to over 100 further countries and territories and to several more languages, putting the surface at more than a billion monthly users by its own count. The expansion was framed as beginning on this date rather than finishing on it, and the individual countries were never enumerated. Any panel that treats a given market as AI Overviews enabled from this date is assuming something the source does not support.
| Vendor announced | |
| Search feature change |
| Google launches AI Overviews for all United States searchers DetailHide detailAt Google I/O 2024, Google announced that AI Overviews would go to every Search user in the United States, retiring the Search Generative Experience label in the process. Google put the reach at hundreds of millions of US searchers within the following week, so the announcement date and the date a given query started returning an AI Overview are different dates. This row records the announcement date and asserts no completion date.
| Vendor announced | |
| Model release |
| OpenAI releases GPT-4o as the ChatGPT default model DetailHide detailOpenAI announced GPT-4o and made it the model serving ChatGPT for both free and paid tiers. The capability set arrived in stages rather than all at once, with text and image handling ahead of voice and full API access, so the interval over which ChatGPT answers actually changed is wider than this single date. The date recorded here comes from contemporaneous reporting rather than a dateline on the vendor page.
| Vendor announced | |
| Search feature change |
| Google announces Search Generative Experience at I/O 2023 DetailHide detailAt Google I/O 2023, Google announced the Search Generative Experience, which placed a generated answer block ahead of the ranked result list for a subset of queries. Access sat behind a Search Labs waitlist at announcement, so the population able to see it grew over an interval Google never bounded publicly. SGE is the direct ancestor of AI Overviews and is seeded so the AI Overviews rows have somewhere to point back to.
| Vendor announced | |
| Model release |
| OpenAI releases ChatGPT as a public research preview DetailHide detailOpenAI opened ChatGPT to anyone as a free research preview, running on a model in the GPT-3.5 series. This row is the registry origin point, marking the first date on which a general audience could get conversational answers to information questions without going to a search engine. The vendor post confirms the release, and the date recorded here comes from contemporaneous reporting rather than a dateline on the vendor page, so the row is capped at vendor_announced.
| Vendor announced |
The row contract is defined in schema/event.schema.json and enforced in CI on every pull request.
Known limits
What this record cannot see.
The registry is a lower bound on how often these surfaces changed. Each limit below is stated on the repository as well, in METHODOLOGY.md.
The registry does not claim completeness
Vendors change the model behind a consumer surface without announcing it, and routing layers shift traffic between variants continuously. Nothing here detects that, so silent model swaps are unobservable and absence of a row is not absence of an event.
Announcement dates are not exposure dates
Most rows anchor to an announcement. The date a population actually saw a change is later by an interval vendors rarely publish, and no row asserts a completion date it cannot source.
Geographic and language coverage is uneven
Vendor announcements about multi country rollouts usually do not enumerate countries. Rows record what the vendor said, so a market cannot be assumed covered on the announcement date.
The registry does not claim causation
It records events and observed volatility with stated confidence. Overlapping events stay separate rows even when the data cannot separate them, and every causal reading belongs to whoever is doing the study.
Citing and contributing
How to cite
Cite the repository and the commit you read.
The file changes as events are added and as attribution tiers are revised, so a citation without a commit points at a moving target.
serp-event-registry, rampstackco. https://github.com/rampstackco/serp-event-registry
Retrieved at commit <sha>.Released under the MIT license. The citation block on the repository is the same one.
How to propose an event
Open a pull request with primary sources.
Add one line to data/events.jsonl, keeping the file sorted by event_date, and include at least one primary source: a vendor blog post, a status page, or an official changelog. Secondary reporting can support a row without carrying it.
Proposals without sources are closed. Where the date is softer than the row claims, the ask is to lower date_precision or attribution rather than to drop the row.