Company lists · Data refreshed September 2026
Top 25 Calendar software developers worldwide
RevenueBase identified 142 calendar software developers worldwide as of September 2026 and tracks 517 professional contacts across them, including 99 with verified work emails. The United States is the largest market and San Francisco the largest hub.
This list covers calendar software developers worldwide, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 27, 2026. Country and city lists for calendar software developers follow the table.
Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.
The 25 largest calendar software developers worldwide
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 48 contacts → | ||||
Indirect evidence “TimeTree 500 TimeTree Apple Best of 2015 App Store Watch App Store App StoreApp VERYLEECHANTO Web10 FacebookFbStart 4 120%#02 Web Designing 20163…” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 2 | 37 contacts → | ||||
Partial evidence “Clockwise is an AI-powered calendar assistant that builds smarter schedules for everyone by coordinating the way individuals, teams, and companies prefer to work.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 3 | 19 contacts → | ||||
Partial evidence “Vimcal is the world's fastest calendar, beautifully designed for people who have too many meetings.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 4 | 19 contacts → | ||||
Indirect evidence “Your 9am class.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 5 | 18 contacts → | ||||
Strong evidence “AddEvent is a cutting-edge software company providing best-in-class calendar marketing and event management solutions to thousands of companies worldwide.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 6 | 17 contacts → | ||||
Indirect evidence “The important stuff doesn't happen just because you write it down.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 7 | 11 contacts → | ||||
Partial evidence “We are Calendar, trying to make the world a much more productive place.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 8 | 9 contacts → | ||||
Indirect evidence “Zersey Infotech is a next-gen tech based company that has many brands under its portfolio.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 9 | 7 contacts → | ||||
Indirect evidence “Mobiscroll helps engineering teams build complex scheduling, appointment booking, planning, and resource management experiences without starting from scratch or getting locked…” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 10 | 7 contacts → | ||||
Partial evidence “Elevate your planning with Lectie's interactive, branded calendars.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 11 | 5 contacts → | ||||
Partial evidence “Forge stronger relationships in every meeting with the only people-centered calendar app.#forgeyournetwork” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 12 | 5 contacts → | ||||
Partial evidence “Stop juggling calendars.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 13 | 5 contacts → | ||||
Partial evidence “Acumen is a powerful and innovative software that helps individuals and teams achieve their goals by maximizing their productivity.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 14 | 4 contacts → | ||||
Indirect evidence “We're the sync experts!” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 15 | 4 contacts → | ||||
Partial evidence “OneCal is a tool that syncs Outlook, iCloud and Google Calendars, provides intuitive scheduling links that make scheduling simple, and allows you to view Outlook, iCloud and…” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 16 | 4 contacts → | ||||
Partial evidence “Fhynix is a daily planner and calendar, built with Open AI, text and voice to help focus on what matters to you and not just tasks and to-dos.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 17 | 4 contacts → | ||||
Partial evidence “ET Labs is a software development company in Austin, Texas devoted to simplicity and productivity.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 18 | 3 contacts → | ||||
Partial evidence “Sparkeey is a mobile calendaring application product with a patented status.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 19 | 3 contacts → | ||||
Strong evidence “Productivity software to run your business on your device anytime -leveraging the cloud, AI and social tools to optimize your calendar experience.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 20 | 3 contacts → | ||||
Partial evidence “Raft is a beautiful and fun calendar app designed for couples, families and close friends that want to sync calendars, spend more time together and have things to look forward to.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 21 | 3 contacts → | ||||
Indirect evidence “In today's fast-paced world, staying on top of your schedule and sharing events seamlessly can be a challenge.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 22 | 3 contacts → | ||||
Indirect evidence “Our user-friendly App lets you effortlessly plan for birthdays, festivals, sports events, holidays, and more.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 23 | 2 contacts → | ||||
Partial evidence “Time Theory Software develops apps for iOS.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 24 | 2 contacts → | ||||
Partial evidence “CalendarBridge helps professionals, teams, and organizations manage their multiple calendars seamlessly and with confidence.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 25 | 2 contacts → | ||||
Indirect evidence “You have messaging apps for chatting.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
RevenueBase Smart Search
RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: calendar software developers. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.
- Strong evidence
- The company's own public description of its business names calendar software developers.
- Partial evidence
- Its own public description names part of calendar software developers, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name calendar software developers. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.
RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.
Showing 25 of 142 calendar software developers worldwide
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Calendar software developers worldwide at a glance
As of Sep 27, 2026Companies by employee count
Email recency is reported on each country list linked below.
How this list was built
Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among calendar software developers, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.
- Source
- The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
- Coverage
- Every country. Country and city lists for calendar software developers are linked below.
- What qualifies
- Companies worldwide whose own description of what they do matches “calendar software developers”. Matching reads each company's description, not its industry code or its name.
- RevenueBase Smart Search
- RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names calendar software developers), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
- What we exclude
- Companies whose own description does not clearly place them among calendar software developers, and records with no verified work email.
- Match quality
- In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
- Ranking
- Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
- Verification
- Every listed company carries at least one verified work email, 99 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
- Refresh
- This page's figures were pulled from the company graph on September 27, 2026. Lists refresh periodically as the graph is re-checked.
- Corrections
- Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.
Calendar software developers by location
1 lists · largest firstEvery Calendar software developers list RevenueBase publishes, by country and city. Counts are matching companies in each list as of its own refresh date.
Countries
Frequently asked
What is RevenueBase Smart Search?
RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names calendar software developers, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.
How many calendar software developers are there worldwide?
RevenueBase identified 142 calendar software developers worldwide as of September 2026, matched on each company's own description of what it does rather than its industry code.
What is the largest company on this list?
株式会社timetree, headquartered in Worldwide, tops this list with the largest team on record.
Which country has the most calendar software developers?
The United States leads with 43 companies. Every calendar software developers list by country and city is linked on this page.
Which city has the most calendar software developers?
San Francisco leads with 5 headquartered companies, followed by Paris (3) and Austin (2).
How do I get contact information for these companies?
A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 99 verified decision-maker contacts tracked across these 142 companies.
How current is this list?
The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 27, 2026.
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About this data
RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase Smart Search, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.