Monday, April 17, 2023 · 5 min read

Series A Memo

Peer Richelsen
Peer RichelsenCo-Founder, Cal.com
Series A Memo

Cal.com is on a mission to connect a billion people by 2031 through calendar scheduling.

Peer Richelsen

Within 9 months, Cal.com (formerly known as Calendso) has grown from an open-source side project to one of the fastest-growing commercial open-source companies.

Hours after the launch, we broke Product Hunt (currently #2 in the race of becoming Product of the Year), HackerNews , Reddit and have been trending for several weeks on GitHub as one of the fastest-growing Typescript repositories.

What initially may have been seen as a hype spike, has now turned into sustainable, predictable growth due to the viral nature of our product:

This week (Jan 5th) the Brazilian Government ( https://calendar.sasi.com.br/ ) is using Cal.com to make appointments for citizens to get ID cards.

1. Category Leader

In a crowded space, full of scheduling products, we’ve carved out a niche and created and now own the category: #OpenScheduling . Only scheduling products that are open, accessible, extensible, and supported by a developer community is part of the Open Scheduling category.

As of today, Cal.com is the category creator and leader of Open Scheduling.

2. Stripe for Time

Stripe is building products to program money.
Cal.com is building products to program time.

Stripe has started out with a simple product offering: Accept Credit Cards on the Web.
Cal.com has started out with a simple product offering: Accept Bookings on the Web.

Stripe has continued to grow deeper and deeper into the financial stack of companies.
Cal.com is looking to grow deeper and deeper into the time scheduling stack of companies.

Example: On Deck is using Cal-as-Infrastructure to facilitate office hours for fellows.

Stripe has kickstarted new financial companies that leverage their payment APIs to program money.
Cal.com is kickstarting new marketplace companies that leverage our scheduling API to program time.

Examples: Telehealth Providers, Hiring Marketplaces, Course-based Fellowships, Online Universities, Freelancer Marketplaces, Government Appointments, Personal Trainer, and Virtual Assistants, …

3. Virality

At its core, Cal.com is inherently viral. By design, scheduling links are meant to be shared. An average active customer has shared their link about 250 times since launch. That is almost one link share per day.

Conservatively speaking, if 10% of attendees convert, a single active customer brings in 25 new customers over 6 months. Of all infrastructure products, we believe only email (i.e. the Gmail launch) has a higher virality coefficient.

4. Stickiness

Calendar products deeply integrate into someone’s workflow and are very sticky. We’ve seen very little churn (mostly users going from Pro back to Free). I believe we only had a handful of “account deletion requests” on a 10,000-strong customer base.

My Calendly subscription would’ve reached its third year if I hadn't started Cal.com instead.
– Peer

5. SEO

Since inception, we’re owning the first page of Google links for “ calendly open source ”, a long-tail keyword that is actively searched by startups, SMBs, and enterprise companies who look for an ”open, accessible, extensible and customizable” Calendly alternative.

Besides that, we’re already ranking for “calendly alternative”, though there is more competition as mentioned in 1. Category Leader.

6. Value

The importance of scheduling

Back in April, we ran a survey and identified that scheduling is a 9/10 priority for the companies we targeted (N>1000). Providing the right scheduling infrastructure is not only a massive value-add for an organization, some businesses would simply not exist without it. (i.e. hiring marketplaces).

Cal.com is not only important for internal meetings but especially for external meetings.

The importance of bookings

Additionally, most bookings on Cal.com are “high-value” interactions.

  • When a VC books a call with a potential founder, the booking has a perceived value in the thousands of dollars

  • Hiring companies pay up to $5,000 per referred employee who jumps on a call

  • A patient meeting their doctor can be life-saving

  • A founder talking to their therapist/coach is priceless

As society interacts more and more on the web, cal.com becomes the door to everyone’s service and creates massive value across all industries.

With an estimated average of $100 “perceived value” per booking and 50,000 bookings per month, we’ve generated $5,000,000 of GTV (Gross time value) in January 2021

7. Community

After just a few months, our Slack has grown to an incredible size of 1,300+ power users, consisting of mostly engineers and entrepreneurs.

GitHub has shown impressive signs of adoption with over 9,000 stars, ~900 forks, and 79 contributors.

Statistics from Orbit , a community-analytics product, shows that out of 12,469 total community members, more than 10% are actively engaging.

8. Open Startup

All of our KPIs are open: cal.com/open

9. Commercialization

B2C SaaS:

As with every SaaS business, our units are very profitable. With $12/month per user, we’re looking at only 7,000 monthly paying customers to make $1M ARR. Team accounts are $19. Premium usernames go for $349/year and we’ve already sold over 200 premium accounts.

The bigger challenge will be converting freemium (self-hosted and free plan) to pro customers, not acquiring new customers.

Go-To-Market: Viral adoption through shared links

B2B Enterprise

Enterprise pricing includes SSO, SCIM, Audit Logs, and much more which enterprise organizations require. Those plans usually start at $150k/year and can go up to seven figures. We have more than 40 enterprise deals in the pipeline and about 300k in ARR LOIs which we need to convert. However, these deals take time and it would be absurd to have closed them already given the young age of Cal.com.

Current customers in the pipeline range from AWS to Canonical to Subcontractors of the DoD and Airforce.

Go-To-Market: Bottom-Up Developer Adoption and Enterprise Sales

B2B Infrastructure

For both Startups to Enterprise companies, we offer an infrastructure deal, where you can leverage the APIs of Cal.com to build a proper new business on top. The previous two use cases are great for sending and receiving bookings but the Infrastructure use case is to offer companies a way to build something like a marketplace, where $12/month/user does not work.

Our pricing for Infrastructure is $149 platform fee/month + $0.05 per booking. More at cal.com/pricing?infra

Go-To-Market: Bottom-Up Developer Adoption and Founder Connections

10. Previous Funding

We’ve raised $7.4M on $60M Post by amazing human beings such as JJ from OSSC, Naval, Balaji S. Srinivasan, James Beshara, Liu Jiang, Tod Sacerdoti, Chad Hurley, Arjun Sethi, Eliot Horowitz, Neha Narkhede, Glenn Solomon, Job van der Voort, Alex Bouaziz, Cassidy Williams and many many more .


This gives us 7 to 10 years of runway, which we intend to keep that long to strengthen our leverage when selling to Enterprise companies and setting up SLAs with min. 5 years of support.

11. This round

We’re looking to raise between $20M to $30M to build out our enterprise and go-to-market team internationally.

12. Vision

We want to build the scheduling infrastructure of the web and believe this can only be achieved by being the most open, transparent, accessible, extensible, and developer-friendly product out there.

To connect one billion people by 2031, we’re looking to hire the best engineers, designers, salespeople, marketers, and community managers the world has to offer. That’s where parts of the next round will go into.

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