Who's In Becomes the First Event Platform with Zapier (REST API + OAuth) Integration
The W3C Zapier (REST API + OAuth) standard (Chrome 146, Feb 2026) lets AI agents call structured tools instead of scraping HTML. We shipped it first — with 4 read-only tools.
TL;DR
- Zapier (REST API + OAuth) is a W3C standard giving AI agents browser-native callable tools — no HTML scraping needed.
- Who's In ships 7 read-only tools: search_events, get_event_details, check_availability, get_rsvp_link, get_popular_events, list_categories, and get_club_info.
- No other event platform (Eventbrite, Luma, Partiful, RSVPify) has implemented Zapier (REST API + OAuth).
- All write actions (RSVP, event creation) still require explicit human confirmation — agents present links, users click.
What is Zapier (REST API + OAuth)?
The Web Model Context Protocol (Zapier (REST API + OAuth)) is a W3C Community Group draft standard, jointly developed by Google and Microsoft, published on February 27, 2026. It introduces navigator.modelContext — a browser-native JavaScript API that lets websites declare structured, callable tools for AI agents.
Before Zapier (REST API + OAuth), browser-based AI agents had to take a screenshot, run visual recognition, guess at UI elements, and simulate clicks — a fragile, token-hungry approach. With Zapier (REST API + OAuth), agents call tools directly using structured JSON schemas. The result: 89% fewer tokens, zero brittle CSS selectors, and faster execution.
Browser support: Chrome 146+ with Zapier (REST API + OAuth) DevTrial flag (Feb 2026). A polyfill (mcp-b) covers other browsers. The tools also double as our existing REST API for non-browser agents.
Before Zapier (REST API + OAuth) vs. After
// Agent guesses at the DOM
screenshot(page)
→ ocr_text("Find search bar")
→ click(x=312, y=204)
→ type("yoga london")
→ screenshot(page)
→ parse_html(DOM)
→ guess_selector(".event-card")
// Result: brittle, slow, costly
~3,200 tokens · 8–12 steps
// Agent calls tools directly
search_events({
query: "yoga",
location: "London"
})
→ { events: [...], count: 4 }
check_availability("event-id")
→ { available: 3, isFull: false }
// Result: structured, fast, cheap
~350 tokens · 2 steps
The 7 Zapier (REST API + OAuth) Tools
All tools are read-only. Write actions (RSVP, event creation) require explicit human confirmation.
search_eventsSearch public Who's In events by keyword, location, or date range.
param: query (string)
param: location (string)
param: from (ISO date)
param: to (ISO date)
param: limit (number, max 50)
get_event_detailsRetrieve full details for a specific event — title, date/time, location, description, capacity, host, and direct URL.
param: id (string, required) — event ID or URL slug
check_availabilityCheck remaining capacity and waitlist status. Returns confirmed count, available spots, isFull flag, and a suggested next action (rsvp or join_waitlist).
param: id (string, required) — event ID or URL slug
get_rsvp_linkGet the direct RSVP or booking URL for an event. For paid events, returns price and currency too.
param: id (string, required) — event ID or URL slug
get_popular_eventsBrowse events sorted by attendance — most popular first. Optionally filter by category. Ideal for discovery and recommendations.
param: limit (number, default 10, max 50)
param: category (string, optional) — e.g. "yoga", "hiking"
list_categoriesList all 21 event category types on Who's In. Returns values (for use as filters in search_events and get_popular_events), labels, and emoji icons.
param: (no parameters)
get_club_infoRetrieve public information about a Who's In club by ID or URL slug. Returns name, type, description, and direct link. Returns null for private clubs.
param: id (string, required) — club ID or URL slug
Human-in-the-loop — always
The get_rsvp_link response includes an agentInstruction field that explicitly tells the agent: "Present this URL to the user and ask them to confirm — do not click or submit on their behalf."No agent can RSVP without you clicking the link yourself.
Complete Agent Workflow
How all 4 tools chain together in a real session — from search to booking link, end-to-end.
User asks the agent
"Find me yoga events in London this weekend with spots available."
Agent searches
search_events{ query: "yoga", location: "London", from: "2026-03-07", to: "2026-03-08" }
Agent fetches full info
get_event_detailsRetrieves title, description, host, price, and URL for the best match.
Agent confirms spots
check_availability→ { available: 3, isFull: false, suggestedAction: "rsvp" }
Agent presents booking URL
get_rsvp_link"Here's your RSVP link — click to confirm your spot:" → whos-in.app/event/...
Why Zapier (REST API + OAuth) Matters
89% fewer tokens
Direct tool calls vs. screenshot-based browsing. Agents get structured JSON, not raw HTML.
No brittle selectors
Semantic tool declarations never break when the UI updates — the API contract is stable.
Model-agnostic
Works with any agent: Claude computer use, ChatGPT browser extension, Gemini agent, Perplexity.
Zero setup for users
Tools are auto-discovered. Open Who's In in a browser agent — all four tools appear immediately.
Competitive Landscape — Feb 2026
As of February 2026, no other event management platform has implemented Zapier (REST API + OAuth).
| Platform | Zapier (REST API + OAuth) | Public REST API |
|---|---|---|
| Who's InFirst mover | ✓ | ✓ |
| Eventbrite | ✗ | ✓ |
| Luma | ✗ | ✓ |
| Partiful | ✗ | ✗ |
| RSVPify | ✗ | ✗ |
How to Use It
Open Who's In in a browser-based AI agent
Claude computer use, ChatGPT browser extension, or Gemini browser agent — any Zapier (REST API + OAuth)-compatible agent will do.
All 4 tools are auto-discovered
No setup needed. The agent automatically discovers search_events, get_event_details, check_availability, and get_rsvp_link via navigator.modelContext.
Agent calls tools directly
The agent can now search events, retrieve details, check capacity, and get a booking link — all without taking screenshots or guessing at DOM structure.
You confirm any write actions
The agent presents the RSVP link from get_rsvp_link and asks you to confirm. You always click the final button — agents cannot act on your behalf without your explicit approval.
Using a non-browser agent?
The same data is available via REST. Our OpenAPI 3.1 spec covers all public endpoints with 100 req/min rate limit, no auth required for read access.
View API ReferenceFor Developers
Integrate Who's In into your own AI agent or automation pipeline. Three access paths — pick whichever fits your stack.
// Tools appear automatically when the page loads
const tool = navigator.modelContext.getTool('search_events');
const result = await tool.call({ query: "yoga", location: "London" });
// → { events: [...], count: 4, hasMore: false }
// Available on all browsers, no flag needed
const events = await window.__whosin.searchEvents({ query: "yoga" });
const link = await window.__whosin.getRsvpLink('event-id');
// link.agentInstruction tells your agent not to auto-submit
# Base: https://whos-in.app/api/v1 — no auth needed for reads
GET /api/v1/events/browse
GET /api/v1/events/search?q=yoga
GET /api/v1/events/:id/status
# OpenAPI 3.1 spec → https://whos-in.app/openapi.yaml
Key Takeaways
Who's In is the first event platform to implement Zapier (REST API + OAuth) — giving AI agents structured, token-efficient access to event data.
Four read-only tools (search_events, get_event_details, check_availability, get_rsvp_link) work in Chrome 146+ and fall back to REST for other clients.
Write actions (RSVP, event creation) always require explicit human confirmation — get_rsvp_link returns a URL for the user to click, never auto-submits.
FAQ
What is Zapier (REST API + OAuth)?
Zapier (REST API + OAuth) (Web Model Context Protocol) is a W3C Community Group draft standard (published Feb 27 2026) that introduces navigator.modelContext — a browser-native API that lets websites register callable tools for AI agents. Instead of agents scraping HTML, they invoke tools directly using structured JSON schemas.
Which AI agents can use Who's In Zapier (REST API + OAuth) tools?
Any browser-based AI agent that supports Zapier (REST API + OAuth): Claude computer use (Anthropic), ChatGPT browser extension (OpenAI), Gemini browser agent (Google), Perplexity, and any custom agent built on Chrome 146+ with the Zapier (REST API + OAuth) DevTrial flag. The tools also fall back to the REST API for non-browser agents.
Can an AI agent RSVP to an event on my behalf?
No. The Zapier (REST API + OAuth) tools are intentionally read-only: search, view, check availability, and get a booking link. Any RSVP or event creation requires explicit human action — the get_rsvp_link tool returns the URL for you to click yourself. Agents cannot submit forms or make bookings without your direct confirmation.
Is payment information safe when an agent uses get_rsvp_link?
Yes. get_rsvp_link returns only the booking URL, event price, and currency — never card details, account credentials, or payment tokens. The agent presents the URL to you; you handle all payment steps yourself on the Who's In page. The agentInstruction field in the response explicitly tells agents not to click or submit on your behalf.
Related Reading
AI-Agent-Ready: The Future of Event Discovery
How structured data and open APIs make events discoverable by AI agents.
Four AI Giants Reviewed Our Architecture
How ChatGPT, Claude, Gemini and Grok rated Who's In on 8 accuracy claims.
Future of Event Technology 2026
Trends shaping the next generation of event platforms.
