Calendly is looking for a Senior Frontend Platform Engineer to join our App Platform team. In this role, you will build the foundational capabilities that power our product ecosystem, focusing on critical services like shared frontend packages, architecture, real-time infrastructure, and developer tooling.

What You'll Do

Design, develop, and maintain services and frameworks that product teams depend on, using technologies like React and Webpack.
Contribute to architectural decisions and technical strategy for the platform that drives the look and feel of our frontend.
Provide guidance to engineers across the organization, share expertise in frontend platform systems, and help establish patterns and practices.
Own and contribute to significant projects from concept to production, such as building real-time infrastructure or optimizing package performance.
Partner with product managers, designers, and engineering teams to translate their needs into robust platform solutions.
Ensure reliability and performance of platform services through thoughtful monitoring, testing, and incident response.
Participate in an on-call rotation to support business-critical systems.

What We're Looking For

6+ years of software engineering experience at a SaaS or technology company, with a strong focus on modern frontend architecture.
Deep expertise in React, TypeScript, and Webpack (or comparable build tooling), including application architecture, dependency management, and performance optimization.
Experience designing and maintaining shared frontend platforms, libraries, and infrastructure used across multiple teams.
Proven ability to own and evolve package ecosystems (versioning, upgrades, migrations, and compatibility across apps).
Experience building systems and processes that keep frontend dependencies up to date, stable, and aligned across teams.
Ability to partner with product engineering teams to improve application architecture, performance, and maintainability in React apps.
Strong debugging skills, with experience diagnosing cross-app issues spanning packages, build systems, runtime behavior, and CI/CD pipelines.
Experience supporting large-scale migrations (e.g., library upgrades, architectural shifts, routing changes, state management transitions).
Familiarity with CI/CD pipelines, release workflows, and automation for frontend packages and applications.
Comfortable acting as a force multiplier: unblocking teams, providing architectural guidance, and reducing single-points-of-failure in the frontend ecosystem.
Strong communication skills, able to collaborate with design system teams, product engineers, and infrastructure partners.
Authorized to work lawfully in the United States of America as Calendly does not engage in immigration sponsorship at this time.

Nice to Have

Background in platform engineering, developer experience (DevEx), or internal tools roles.
Experience with micro-frontend (MFE) architecture, including module federation, build, deployment, and integration pipelines.
Experience authoring shared packages from scratch (e.g. datetime utilities, SSE / Server-Side Event clients, custom eslint rules).
Experience with RTK Query cache architecture, including cache tags, optimistic updates, and strongly-typed API layers.
Experience with Storybook infrastructure and migrations, including CI integration and version upgrades.
Experience with analytics, experimentation, or feature flagging SDKs/infrastructure.

Technical Stack

React
TypeScript
Webpack

Team & Environment

You will join the App Platform team, a collaborative environment where we are energized by enabling others to ship with confidence. Our culture values leading with curiosity, assuming positive intent, and investing in the people around you.

Benefits & Compensation

Top Performer Bonus program (or Sales incentive)
Equity awards
Competitive benefits
Compensation: Salary tiers based on location and experience: Tier 1: $224,400 - $271,920 USD. Tier 2: $205,700 - $249,260 USD. Tier 3: $187,000 - $226,600 USD.