Principal Full Stack Engineer

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What Calendly is looking for in applicants

What is Calendly?

Calendly takes the work out of scheduling so our customers have more time to work on what’s really important. Our software is used by millions of people worldwide—with thousands more signing up every day. To maintain this exciting growth, we’re looking for top talent to join our team and help shape the future of our product.

Why join Calendly’s Engineering team? 

As a Principal Engineer focused on Calendly’s APIs, you have the chance to help lead the design and development of our public API as well as helping define our internal API strategy.  In doing this you will help mentor and grow some of the best and brightest engineers in the world. You will be working with the company's senior leadership, architecture, and product teams to conceive, design, and plan the implementation of major API-first efforts while also rolling up your sleeves and working with engineers on the build and launch phases of an effort.  As a technical leader you bake quality and reliability into your work at every step, focusing not just on the initial delivery but also evolvable design and scalability.

Calendly is built using a service-oriented architecture and an automated continuous delivery system in order to efficiently deliver our product solutions.  To be successful, you will need to help conceive, design, and build well-tested software. You will be using technologies such as Elasticsearch, Google Cloud Platform, Kubernetes, Ruby on Rails, Node, TypeScript, React, PostgreSQL, Redis, and more. 

What are some of the high impact opportunities you’ll tackle? 

  • Evolve the software development lifecycle by advancing industry best practices in order to improve the ability of Calendly to ship production ready code
  • Partner with architecture in the creation and execution of a multi-year, API-first technology strategy for Calendly while contributing to the engineering roadmap
  • Champion the migration to a distributed services architecture and the adoption of API-first development
  • Define, implement, and rollout new patterns and practices for a particular technology or product function that are adopted by the broader engineering team
  • Work across scrum teams, architects, and with other stakeholders to deliver enterprise-level value to Calendly’s customers 
  • Build out greenfield systems using the best technology choice for the job in order to tackle the most difficult technical challenges Calendly will face
  • Lead presentations internally and externally on Calendly's technology solutions

This opportunity is for you if you have/are:

  • 12+ years of professional development experience with expert level proficiency across multiple technologies
  • Experience working with and/or developing RESTful and event-driven APIs for internal and external use
  • Experience in driving microservices architecture
  • Experience implementing an API gateway
  • Experience creating and mentoring API teams
  • A proven track record of planning, guiding, and consistently delivering complex, high volume systems
  • Deep experience creating innovative solutions that have a broad impact across an organization or the broader developer community
  • Experience designing and implementing testable systems with a focus on reliability, performance, and scalability
  • Great communication skills and the ability to succinctly explain complex technical concepts to all roles in the organization
  • Extensive experience working within a cross functional team balancing product and engineering needs
  • A Bachelor’s degree in Computer Science or related field, or comparable work experience
  • Authorized to work lawfully in the United States of America as Calendly does not engage in immigration sponsorship at this time 

Bonus if you have experience with:

  • An advanced degree in Computer Science or related field
  • Filing and obtaining patents based on your work
  • Significant contributions to open source software that is applicable to your role and the work you do
  • Deep experience in a core technology that Calendly uses (e.g. Calendar APIs, Ruby/Rails optimization, Database optimization, Authentication/Authorization)
  • Extensive expertise in building high-availability systems that conform to strict SLAs
  • Maintaining, contributing, or giving tech talks about an open source technology that we use at Calendly

If you are an individual with a disability and would like to request a reasonable accommodation as part of the application or recruiting process, please contact us at

Calendly is registered as an employer in many, but not all, states. If you are not located in or able to work from a state where Calendly is registered, you will not be eligible for employment.

Want some tips on how to get an interview at Calendly?

What is Calendly looking for?
If this role looks interesting to you, a great first step is to understand what excites you about the team, product or mission. Take your time thinking about this and then tell the team! Get in touch and communicate that passion.
What are interviews for Principal Full Stack Engineer like?
Interview processes vary by company, role and team. The best plan is to see what others have experienced and then plan accordingly.
How to land an interview at Principal Full Stack Engineer?
A great first step is organizing your path to an offer. Check out Kiter for tools to get started!