Calendar
Variants seen in the corpus:
Calendarcalendar
Providers using this tag (51)
Ranked by API Evangelist rating — Exemplar and Strong are expanded by default.
Exemplar 1 Complete, well-documented, and agent-ready
Strong 7 Solid coverage with minor gaps
Developing 9 Usable, with meaningful gaps to close
Thin 8 Limited public surface area
Minimal 18 Almost no public developer surface
Unrated 1 Not yet scored
APIs with this tag (84)
Ranked by the provider's API Evangelist rating — the Kin Score is scored per provider, not per API, so every API of a provider shares its band. How the rating works →
Exemplar 1 Complete, well-documented, and agent-ready
Strong 11 Solid coverage with minor gaps
Dow Jones Calendar Live APISearch and retrieve Dow Jones economic, corporate, treasury and IPO calendar events, with a full set of tax...Clear Street Calendar APIAccess clocks and financial calendars for market sessions and events.Unified.to calendar APIThe calendar API from Unified.to — 11 operation(s) for calendar.CycleCalcs MCP ServerHosted stateless Streamable HTTP MCP server exposing 11 astronomy tools backed by the v2 REST endpoints. Re...ThetaData Calendar APIThe Calendar API from ThetaData — 3 operation(s) for calendar.EODHD Calendar APICalendar events including earnings, IPOs, splits, dividends, and trendsEODHD Economic Events Calendar APIProvides a global economic calendar of macroeconomic releases including country, event name, scheduled time...Microsoft Calendar APIAccess and manage Outlook calendar eventsAlpaca Calendar APIThe Calendar API from Alpaca — 2 operation(s) for calendar.ECI Office Integration APIMicrosoft 365 integration for ECI products: drive files, mail and calendar for the signed-in user, with nex...Microsoft Office 365 Calendar APIAccess and manage Outlook calendar events, calendars, and calendar groups. Supports scheduling, meeting man...
Developing 33 Usable, with meaningful gaps to close
SIC Clearing Day Calendar APIScheduling information for the electronic payment services provided by SIX Interbank Clearing Ltd - clearin...Zoho CalendarThe Zoho Calendar API provides REST endpoints to customize calendar features, allowing you to manage calend...Zoom Calendar APIThe Zoom Calendar API enables developers to manage calendar events, automate scheduling, sync across platfo...University of Warsaw calendar APIAcademic calendar eventsCIP Events REST APIThe only live, callable REST API the Civil Infrastructure Platform serves: the community event calendar beh...Ritten Calendar APIThe calendar API from Ritten — 2 operation(s) for calendar.Outlook Mail APIAPI for accessing and managing email, calendar, contacts, and tasks in Outlook.Google Calendar APICreate and manage calendars, events, and attendees.Hostaway Calendar APIRead and update the per-listing availability and nightly pricing calendar. Supports per-day retrieval, batc...Charthop calendar APIThe calendar API from Charthop — 10 operation(s) for calendar.VaultRE Calendar APIOperations related to calendar eventsEOD Historical Data Calendar APICalendar events including earnings, IPOs, splits, dividends, and trendsWispr AI Calendar APIThe Calendar API from Wispr AI — 6 operation(s) for calendar.KolayIK Calendar APIThe Calendar API from KolayIK — 5 operation(s) for calendar.TreasurySpring Calendar APIGet Calendar informationPurdue Events Calendar API (Localist tenant)Purdue's public events calendar at events.purdue.edu serves a live JSON events API on the Localist v2 contr...Nittei Scheduler APINittei is MeetsMore's self-hosted calendar and scheduler server, written in Rust (Axum + SQLx + PostgreSQL)...Kumospace Calendar APIThe Calendar API from Kumospace — 7 operation(s) for calendar.Aramark Marko CalendarGiven a day or date range this API has methods to list: * fiscal day attributes * operational day attributesSJTU Open APIThe university's own REST API platform (开放API), operated by the SJTU Network and Information Center at api....airbnb Calendar APIOperations for managing listing availability, pricing, and calendar synchronization across platforms.EPFL Memento Events APIEPFL's public events and agenda API, serving the Memento calendar — events, mementos, registrations, domain...GuestReady Calendar APIThe calendar API from GuestReady — 2 operation(s) for calendar.Employ Inc Events Calendar REST APIThe Events Calendar REST API (tribe/events/v1) for Employ, Inc. events and webinars, with a self-describing...Employ Inc TEC Events REST APIThe newer tec/v1 generation of The Events Calendar REST API on www.employinc.com, published as a self-descr...CCP Games Calendar APIThe Calendar API from CCP Games — 3 operation(s) for calendar.HPSF Events APIThe stable Events Calendar v1 REST API on hpsf.io, serving HPSF's conference and event calendar as JSON - H...HPSF Events Calendar TEC v1 APIThe newer Events Calendar tec/v1 REST API on hpsf.io - an OpenAPI 3.0.4 contract with 17 operations over ev...CrunchDAO calendar APIThe calendar API from CrunchDAO — 2 operation(s) for calendar.EVE Online Calendar APIThe Calendar API from EVE Online — 6 operation(s) for calendar.Fountain Hire API v2REST API for the Fountain Hire product, covering applicants (create, retrieve, update, delete, list, latest...D2L Brightspace Calendar APICourse calendar events.UF Events Calendar (LiveWhale tenancy)The UF events calendar runs on LiveWhale Calendar. calendar.ufl.edu CNAMEs to ufl-prod.lwcal.com — again a ...
Thin 19 Limited public surface area
Bitrix24 Calendar APIThe Calendar API from Bitrix24 — 21 operation(s) for calendar.Bitrix24 REST APITenant-scoped REST API for managing CRM entities, deals, leads, tasks, calendars, telephony, disk files, us...Xignite Earnings Calendar APICompany earnings announcement dates and earnings calendar data from the earningscalendar.xignite.com service.Hospitable Calendar APINightly availability, pricing, and restrictions per property.Planning Center Calendar APIChurch calendaring, events, and facility resources.PetExec Calendar APICompany-wide and per-owner reservation calendars by date range.Microsoft 365 Calendar APIThe Calendar API from Microsoft 365 — 1 operation(s) for calendar.Microsoft Graph APIUnified REST API providing a single endpoint to access data and intelligence across Microsoft 365, Microsof...Cornell Events Calendar API (Localist) — tenantThe Cornell events calendar at events.cornell.edu answers a live JSON API at /api/2/events, and the data is...TableCheck calendar APIThe calendar API from TableCheck — 1 operation(s) for calendar.Uplisting Calendar APIAvailability, prices, and restrictions per property and date.Microsoft Graph APIThe primary API for Office 365, providing access to data and intelligence in Microsoft 365, Windows 10, and...Outlook Calendar APIAccess and manage calendar events, meeting requests, and calendar groups.Moon-API Calendar APIThe Calendar API from Moon-API — 1 operation(s) for calendar.Vetspire Schedule & Appointments APIGraphQL operations over the Schedule domain - list appointments for a location and date range, read provide...Acuity Scheduling REST API v1REST API for managing appointments, appointment types, clients, calendars, availability, intake forms, prod...Clockwise REST APIREST API for the Clockwise AI calendar optimization platform, providing programmatic access to focus time m...EDI Central Bank Calendar APICentral bank meeting and announcement calendar via the GetLatestCentralBankCalendar endpoint.EDI Economic Calendar APIForward-looking economic calendar events via the GetLatestEconomicCalendar endpoint.
Emerging 6 Early or largely undocumented
Norish Recipe APIThe HTTP API each Norish instance serves under /api/v1, covering a public health check plus authenticated r...GroupWise Web Services (SOAP)Server-side SOAP protocol for reading and writing a GroupWise user's mailbox, spoken directly to the GroupW...Webex Hybrid Services APIManage Webex Hybrid Calendar, Hybrid Call Service, Hybrid Message, Video Mesh nodes, and other connectors t...Dentrix Appointments & Scheduling APIRead the schedule and book, reschedule, or cancel appointments. In the Dentrix Developer Program this maps ...TherapyNotes Scheduling API (Modeled)Modeled capability area for appointments, recurring schedules, and reminders. TherapyNotes offers native on...LEAP Calendar APIModeled calendar/diary and appointment-scheduling surface, evidenced by production Marketplace scheduling i...
Minimal 14 Almost no public developer surface
CEPS Events ListingsCEPS maintains a public calendar of policy events, conferences, task force meetings, roundtables and webina...Church CalendarCatholic liturgical calendarHebrew CalendarConvert between Gregorian and Hebrew, fetch Shabbat and Holiday times, etcLectServeProtestant liturgical calendarNager.DatePublic holidays for more than 90 countriesNamedays CalendarProvides namedays for multiple countriesNon-Working DaysSimple REST API for checking working, non-working or short days for Russia, CIS, USA and otherPublic HolidaysData on national, regional, and religious holidays via APIUK Bank HolidaysBank holidays in England and Wales, Scotland and Northern IrelandFestivo Public HolidaysFastest and most advanced public holiday and observance service on the marketNon-Working DaysDatabase of ICS files for non working daysRussian CalendarCheck if a date is a Russian holiday or notCzech Namedays CalendarLookup for a name and returns nameday dateExamity Appointments (Scheduling) APICreate, reschedule, and cancel proctoring appointments for a test-taker against a registered exam, and quer...
Companies reaching this through an API (58)
These companies publish an API, specification or operation carrying “Calendar” but do not classify their business under it. Listed unranked and kept out of the count above, because one tagged operation is not a statement about what a company does.
Airbnb
Alpaca
AlphaAI
Aramark
Bitrix24
CCP Games
CEPS (Centre for European Policy Studies)
Charthop
Cisco Collaboration Hybrid Solutions
Civil Infrastructure Platform
Clear Street
Cornell University
CrunchDAO
D2L Brightspace
Dentrix
Dow Jones Developer Platform
ECI Solutions
Employ Inc
EOD Historical Data
EODHD
EPFL
EVE Online
Examity
Exchange Data International
Fountain
GuestReady
High Performance Software Foundation
Hospitable
Hostaway
KolayIK
Kumospace
LEAP
Microsoft
Microsoft Office
Microsoft Office 365
Moon-API
Novell
Office 365
PetExec
Planning Center
Purdue University
Ritten
Shanghai Jiao Tong University
SIX
TableCheck
TherapyNotes
ThetaData
TreasurySpring
Unified.to
University of Florida
Score breakdown
Frequency
61.3
log-scaled weighted occurrences
Breadth
1.4
spread across providers
Quality lift
31.9
mean composite of providers using it
Cohesion
11.1
strength of nearest seed neighbor
Related tags
Meetings 19 co-occurrences
Scheduling 37 co-occurrences
Mail 11 co-occurrences
Productivity 26 co-occurrences
Holidays 7 co-occurrences
Email 19 co-occurrences
Calendars 7 co-occurrences
Appointments 10 co-occurrences
Where this tag comes from
Provider tag51
Api tag83
Openapi tag31
Openapi op tag110
Cohort brief
Auto-generatedThe 46 providers in the APIs.io catalog tagged Calendar, scored on the Kin Score. Every figure below is computed from the catalog — nothing here is written.
Providers
46
all scored
Mean Kin Score
30
+6.1 vs catalog 23.9
Mean Agent Readiness
15.6
+3.6 vs catalog 12
Spread
5–76.6
median 29.6 · σ 20.4
How the 46 split by band
Exemplar 1Strong 7Developing 9Thin 8Emerging 7Minimal 14
Facet averages, against the whole catalog
| Facet | This cohort | Catalog | Difference | Scored |
|---|---|---|---|---|
| Contract Quality | 30.5 | 19.8 | +10.7 | 46 |
| Access Clarity | 34.9 | 26.5 | +8.4 | 46 |
| Operational Transparency | 19.1 | 14 | +5.1 | 46 |
| Developer Ergonomics | 28.4 | 23.4 | +5 | 46 |
| Discoverability | 63.9 | 61.2 | +2.7 | 46 |
| Contract Governance | 7 | 6.4 | +0.6 | 46 |
A facet is averaged over the members that carry it, not over the whole cohort — the “Scored” column is that count. Averaging an absent facet as zero would score our own coverage gaps as the providers’ posture.
What this cohort publishes
| Artifact | This cohort | Catalog | Difference |
|---|---|---|---|
| MCP server (any) | 13% | 10% | +3 |
| MCP server (first-party) | 17% | 13% | +4 |
| Agent Skills | 0% | 0% | 0 |
| OAuth scopes | 15% | 11% | +4 |
| Security | 98% | 97% | +1 |
| Arazzo workflows | 9% | 2% | +7 |
| Governance rules | 23% | 14% | +9 |
mcp_pct counts any mcp/ artifact including ones API Evangelist derived from the provider OpenAPI; mcp_first_party_pct counts only servers the provider publishes. Prefer the latter.
Top by Kin Score
- 1 Nylas 76.6
- 2 CycleCalcs 63.5
- 3 Microsoft Outlook 63.3
- 4 Chili Piper 63.1
- 5 Amazon WorkMail 59
- 6 Microsoft Exchange 56.4
- 7 Calendarific 55.6
- 8 Checkiday - National Holiday and Event API 54.6
- 9 Google Workspace 50.6
- 10 Holiday API 50.5
Top by Agent Readiness
- 1 Nylas 59.3
- 2 CycleCalcs 49.4
- 3 Chili Piper 47.1
- 4 Microsoft Outlook 46
- 5 Microsoft Exchange 33
- 6 SavvyCal 32.7
- 7 Cal.com 31.2
- 8 Calendarific 31
- 9 API Calendrier Marocain | Jours Fériés & Ouvrables REST + SDK Python 31
- 10 Amazon WorkMail 27.3
All 51 members of this roster resolve to a scored provider in
the catalog.Generated from the catalog build of
15 September 2026, across 27661
providers, using the same computation served by the
APIs.io cohort API. Briefs are published for rosters of
5 or more scored providers; below that a distribution is not meaningful.
Work with this as data
Every tag here is available over the APIs.io API and to AI agents over MCP.