Calendar
Business capabilities this tag reaches
Travel Revenue & Yield Management 1
Patient Access Management 1
Payments & Card Management 1
Variants seen in the corpus:
CalendarsCalendar
Providers using this tag (57)
Ranked by API Evangelist rating — Exemplar and Strong are expanded by default.
Exemplar 3 Complete, well-documented, and agent-ready
Strong 6 Solid coverage with minor gaps
Developing 9 Usable, with meaningful gaps to close
Emerging 11 Early or largely undocumented
Minimal 20 Almost no public developer surface
APIs with this tag (111)
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 10 Complete, well-documented, and agent-ready
Nylas Calendar APIThe Nylas Calendar API allows you to create and manage calendars, and access the events they contain. Nylas...Eventwren Posts APIPost event listings to Eventwren from an AI agent: submit an event listing for moderation ($1 per event, re...ActiveCampaign Calendars APIThe Calendars API from ActiveCampaign — 2 operation(s) for calendars.ZnanyLekarz Calendars APISimple operations on the calendar belonging to the addressGoogle Calendars APIOperations related to CalendarsCisco XDR Calendars APIThe Calendars API from Cisco XDR — 3 operation(s) for calendars.Microsoft Calendar APIAccess and manage Outlook calendar eventsCycleCalcs MCP ServerHosted stateless Streamable HTTP MCP server exposing 11 astronomy tools backed by the v2 REST endpoints. To...HighLevel Calendars APIDocumentation for Calendars APIAlphaAI Calendar APIScheduled US macro releases (FOMC, CPI, jobs, GDP, PCE…).
Strong 21 Solid coverage with minor gaps
Bentley Systems Calendars APICalendars resources for the iTwin Schedules API.Unified.to Calendar APIThe calendar API from Unified.to — 11 operation(s) for calendar.Zoho CalendarThe Zoho Calendar API provides REST endpoints to customize calendar features, allowing you to manage calend...Microsoft Office 365 Calendar APIAccess and manage Outlook calendar events, calendars, and calendar groups. Supports scheduling, meeting man...Outlook Calendar APIAccess and manage calendar events, meeting requests, and calendar groups.APIVerve Calendar APIThe Calendar API from APIVerve — 5 operation(s) for calendar.Clear Street Calendar APIAccess clocks and financial calendars for market sessions and events.Google Calendar APICreate and manage calendars, events, and attendees.Google Workspace APIs Calendar APIThe Calendar API from Google Workspace APIs — 3 operation(s) for calendar.Sifflet Calendars APIThe Calendars API from Sifflet — 2 operation(s) for calendars.ThetaData Calendar APIThe Calendar API from ThetaData — 3 operation(s) for calendar.Microsoft Exchange Calendars APIOperations for managing calendarsCharthop Calendar APIThe calendar API from Charthop — 10 operation(s) for calendar.FOLIO Calendar APIThe Calendar API from FOLIO — 4 operation(s) for calendar.Zoom Calendar APIThe Zoom Calendar API enables developers to manage calendar events, automate scheduling, sync across platfo...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...FXMacroData Calendar APIStandalone economic and policy release calendar endpoint spanning announcements and central-bank decision t...KISI Calendars APIThe Calendars API from KISI — 1 operation(s) for calendars.Outlook Mail APIAPI for accessing and managing email, calendar, contacts, and tasks in Outlook.2s Calendar APIThe calendar API from 2s — 4 operation(s) for calendar.
Developing 34 Usable, with meaningful gaps to close
Alpaca Calendar APIThe Calendar API from Alpaca — 2 operation(s) for calendar.Everbridge Calendars APIEB Suites - Calendars ManagementSAP BI Tools Calendars APIManage calendar events and tasks used for planning workflows and scheduling in SAP Analytics Cloud.SIC Clearing Day Calendar APIScheduling information for the electronic payment services provided by SIX Interbank Clearing Ltd - clearin...Clio Calendars APICalendars contain Calendar Entries. All Clio accounts contain one firm Calendar ("AccountCalendar"), person...VaultRE Calendar APIOperations related to calendar eventsBlue Prism Calendars APIThe Calendars API from Blue Prism — 8 operation(s) for calendars.Clearstreet8e71 Calendar APIAccess clocks and financial calendars for market sessions and events.Ritten Calendar APIThe calendar API from Ritten — 2 operation(s) for calendar.Trakt Calendars APIUpcoming and recently aired schedules for shows, episodes, and movies.Yoxel Calendars APIEach account connected to Aurino can have zero or more calendars, and each calendar has a collection of ind...KolayIK Calendar APIThe Calendar API from KolayIK — 5 operation(s) for calendar.Nittei Scheduler APINittei is MeetsMore's self-hosted calendar and scheduler server, written in Rust (Axum + SQLx + PostgreSQL)...EarningsCall Calendar APIThe Calendar API from EarningsCall — 1 operation(s) for calendar.Hostaway Calendar APIRead and update the per-listing availability and nightly pricing calendar. Supports per-day retrieval, batc...Google Calendar Calendars APIThe Calendars API from Google Calendar — 6 operation(s) for calendars.TreasurySpring Calendar APIGet Calendar informationairbnb Calendar APIOperations for managing listing availability, pricing, and calendar synchronization across platforms.Microsoft Project Calendars APIManage enterprise calendarsEVE Online Calendar APIThe Calendar API from EVE Online — 6 operation(s) for calendar.Kumospace Calendar APIThe Calendar API from Kumospace — 7 operation(s) for calendar.Moment Calendar APIThe Calendar API from Moment — 1 operation(s) for calendar.GuestReady Calendar APIThe calendar API from GuestReady — 2 operation(s) for calendar.CCP Games Calendar APIThe Calendar API from CCP Games — 3 operation(s) for calendar.University of Warsaw Calendar APIAcademic calendar eventsReclaim.ai Calendars APIThe calendars API from Reclaim.ai — 20 operation(s) for calendars.CrunchDAO Calendar APIThe calendar API from CrunchDAO — 2 operation(s) for calendar.Aiera Calendar APIThe Calendar API from Aiera — 3 operation(s) for calendar.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...Magic Moment Calendars APIThe calendars API from Magic Moment — 4 operation(s) for calendars.Reonic Calendars APIReonic-hosted calendars only. External calendar integrations (Google, Microsoft) are visible inside the Reo...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...
Thin 20 Limited public surface area
Xignite Earnings Calendar APICompany earnings announcement dates and earnings calendar data from the earningscalendar.xignite.com service.Xignite Global Holidays APIExchange trading hours, market holidays, and calendar data for global exchanges from the globalholidays.xig...Indian Institute of Technology Bombay Calendar APIThe calendar API from Indian Institute of Technology Bombay — 11 operation(s) for calendar.Cal.com Calendars APIThe Calendars API from Cal.com — 9 operation(s) for calendars.Cal.com REST API v2REST API providing full programmatic control over Cal.com resources including calendars, event types, booki...EPFL Memento Events APIEPFL's public events and agenda API, serving the Memento calendar — events, mementos, registrations, domain...UF Events Calendar (LiveWhale tenancy)The UF events calendar runs on LiveWhale Calendar. calendar.ufl.edu CNAMEs to ufl-prod.lwcal.com — again a ...Purdue 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...Luma Calendars APIThe Calendars API from Luma — 25 operation(s) for calendars.Shanghai Jiao Tong University Calendar APICalendar event synchronisation into the campus calendar.Guesty Calendars APIListing availability and pricingCornell 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...Planning Center Calendar APIChurch calendaring, events, and facility resources.Fountain Hire API v2REST API for the Fountain Hire product, covering applicants (create, retrieve, update, delete, list, latest...Cronofy Calendars APIConnected calendars, application calendars, and account identity.Webex Hybrid Services APIManage Webex Hybrid Calendar, Hybrid Call Service, Hybrid Message, Video Mesh nodes, and other connectors t...Acuity Scheduling REST API v1REST API for managing appointments, appointment types, clients, calendars, availability, intake forms, prod...D2L Brightspace Calendar APICourse calendar events.Hospitable Calendar APINightly availability, pricing, and restrictions per property.TableCheck Calendar APIThe calendar API from TableCheck — 1 operation(s) for calendar.
Emerging 9 Early or largely undocumented
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.PetExec Calendar APICompany-wide and per-owner reservation calendars by date range.GroupWise Web Services (SOAP)Server-side SOAP protocol for reading and writing a GroupWise user's mailbox, spoken directly to the GroupW...Norish Recipe APIThe HTTP API each Norish instance serves under /api/v1, covering a public health check plus authenticated r...Uplisting Calendar APIAvailability, prices, and restrictions per property and date.Vetspire Schedule & Appointments APIGraphQL operations over the Schedule domain - list appointments for a location and date range, read provide...Horoscope API Calendar APILocation-based daily calendar and Sun/Moon data.Dentrix Appointments & Scheduling APIRead the schedule and book, reschedule, or cancel appointments. In the Dentrix Developer Program this maps ...
Minimal 17 Almost no public developer surface
HireVue Coordinate (Scheduling) APIAutomated interview scheduling and coordination across candidate and interviewer calendars. Supports self-s...CEPS Events ListingsCEPS maintains a public calendar of policy events, conferences, task force meetings, roundtables and webina...Hebrew CalendarConvert between Gregorian and Hebrew, fetch Shabbat and Holiday times, etcUK Bank HolidaysBank holidays in England and Wales, Scotland and Northern IrelandLEAP Calendar APIModeled calendar/diary and appointment-scheduling surface, evidenced by production Marketplace scheduling i...Church CalendarCatholic liturgical calendarLectServeProtestant 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 APIFestivo Public HolidaysFastest and most advanced public holiday and observance service on the marketExamity Appointments (Scheduling) APICreate, reschedule, and cancel proctoring appointments for a test-taker against a registered exam, and quer...Czech Namedays CalendarLookup for a name and returns nameday dateNon-Working DaysDatabase of ICS files for non working daysRussian CalendarCheck if a date is a Russian holiday or notClockwise REST APIREST API for the Clockwise AI calendar optimization platform, providing programmatic access to focus time m...
Companies reaching this through an API (73)
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.
2s
ActiveCampaign
Aiera
Airbnb
Alpaca
AlphaAI
APIVerve
Bentley Systems
Blue Prism
CCP Games
CEPS (Centre for European Policy Studies)
Charthop
Cisco Collaboration Hybrid Solutions
Cisco XDR
Clear Street
Clearstreet8e71
Clio
Cornell University
CrunchDAO
D2L Brightspace
Dentrix
EarningsCall
EODHD
EPFL
EVE Online
Everbridge
Examity
Exchange Data International
FOLIO
Fountain
FXMacroData
Google
GuestReady
Guesty
HighLevel
HireVue
Hospitable
Hostaway
Indian Institute of Technology Bombay
KISI
KolayIK
Kumospace
LEAP
Magic Moment
Microsoft
Microsoft Office
Microsoft Office 365
Microsoft Project
Moment
Novell
Show all 73 companies ↓
Score breakdown
Frequency
64.8
log-scaled weighted occurrences
Breadth
1.3
spread across providers
Quality lift
28.5
mean composite of providers using it
Cohesion
11.1
strength of nearest seed neighbor
Related tags
Scheduling 40 co-occurrences
Mail 13 co-occurrences
Meetings 18 co-occurrences
Productivity 25 co-occurrences
Availability 11 co-occurrences
Contacts 23 co-occurrences
Appointments 12 co-occurrences
Email 22 co-occurrences
Where this tag comes from
Api tag111
Provider tag58
Openapi tag55
Openapi op tag239
Cohort brief
Auto-generatedThe 51 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
51
of 57 in the catalog
Mean Kin Score
30.1
+7.9 vs catalog 22.2
Mean Agent Readiness
18.1
+6.1 vs catalog 12
Spread
0–87.5
median 27.3 · σ 22.8
How the 51 split by band
Exemplar 3Strong 6Developing 9Thin 8Emerging 11Minimal 14
Facet averages, against the whole catalog
| Facet | This cohort | Catalog | Difference | Scored |
|---|---|---|---|---|
| Contract Quality | 30.3 | 17.2 | +13.1 | 51 |
| Developer Ergonomics | 30.9 | 23.2 | +7.7 | 51 |
| Operational Transparency | 20.1 | 13 | +7.1 | 51 |
| Access Clarity | 30.5 | 23.9 | +6.6 | 51 |
| Contract Governance | 9.7 | 6.5 | +3.2 | 51 |
| Discoverability | 58.6 | 57.9 | +0.7 | 51 |
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) | 20% | 13% | +7 |
| MCP server (first-party) | 20% | 12% | +8 |
| Agent Skills | 0% | 0% | 0 |
| OAuth scopes | 16% | 11% | +5 |
| Security | 100% | 98% | +2 |
| Arazzo workflows | 8% | 2% | +6 |
| Governance rules | 33% | 16% | +17 |
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 87.5
- 2 Eventwren 85.6
- 3 CycleCalcs 67.1
- 4 Chili Piper 66.1
- 5 Microsoft Outlook 65.9
- 6 Google Workspace 60.4
- 7 Microsoft Exchange 58.7
- 8 Amazon WorkMail 57.6
- 9 Business Box 56.1
- 10 Calendarific 49.2
Top by Agent Readiness
- 1 Eventwren 75
- 2 Nylas 57.2
- 3 Chili Piper 56.3
- 4 CycleCalcs 49.4
- 5 Cal.com 49.2
- 6 Microsoft Outlook 48.6
- 7 SavvyCal 48.1
- 8 Luma 45.9
- 9 Business Box 34.5
- 10 Microsoft Exchange 30.5
All 57 members of this roster resolve to a provider in the
catalog; 51 carry a score (89%).
The figures above describe the scored members only.
Coverage caveat. 38 of 51 scored members had under half their catalog-attributable points satisfied at all (catalog_earned / catalog_max < 0.5). They are INCLUDED in the mean above. A large share here means the cohort mean is partly a measurement of how far our enrichment reached, not only of how these providers publish.Generated from the catalog build of 24 October 2026, across 31984 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.
Coverage caveat. 38 of 51 scored members had under half their catalog-attributable points satisfied at all (catalog_earned / catalog_max < 0.5). They are INCLUDED in the mean above. A large share here means the cohort mean is partly a measurement of how far our enrichment reached, not only of how these providers publish.Generated from the catalog build of 24 October 2026, across 31984 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.