The no1. conversations platform for mobile apps.

Software Engineer - Platform Team

$100K - $160K / 0.25%
400 1st Ave, San Mateo, CA 94401
Job Type
3+ years
Apply to Sendbird and hundreds of other fast-growing YC startups with a single profile.
Apply to role ›

About the role

At SendBird, we are building the most scalable and powerful chat API in the world. We have customers from over 150 countries and serve a wide-range of use-cases across communities, marketplaces, on-demand services, games, and e-commerce. After graduating from Y Combinator in Feb 2018, we raised a $16M series A round led by Shasta Ventures and August Capital and have become one of the fastest growing startups in Silicon Valley.

We are headquartered in San Mateo, CA and have an APAC office in Seoul, South Korea.

The engineering team at SendBird is solving some of the biggest challenges related to building reliable, feature-rich, and scalable real-time conversational experiences across different platforms. The challenges range from building a platform that can scale to some of the largest user-bases across distributed environments with optimal latency; creating a feature-rich yet lightweight and high performance client-side SDK; and building products and services that can help customers incorporate real-time conversational technologies more rapidly.


  • Build a large scale distributed and scalable real-time messaging service
  • Design simple, intuitive API to solve complex architectural problems
  • Write customer-centric documentation on API and messaging services
  • Architect and build efficient servers on our globally distributed infrastructure
  • Deploy and operate server clusters within a cloud environment


  • Working knowledge of Java or Python with at least 2 years of experience developing, shipping, and maintaining real-time systems
  • Have deep understanding of multi-threading and high performance distributed architecture
  • Able to work independently and drive results
  • Ability to find the root cause of problems with a minimal set of information and data points
  • Ability to find the optimal solution given the resource constraints, and understands the concepts of under-engineering and over-engineering


  • Experience working on a real-time chat/messaging system
  • Experience handling massive concurrent connections and processing large-scale traffic
  • Understanding of Unix/Linux systems
  • Understanding of Python, Java, and Event-Driven Frameworks
  • Understanding of TCP/IP and network programming
  • Understanding of RDBMS, NoSQL and distributed databases
  • Understanding of server virtualization, global infrastructures, load balancing, and handling massive data traffic
  • Awards from programming competitions (e.g., ACM ICPC, IOI, etc.)

About Sendbird

At Sendbird, we are building the world's leading conversations platform for mobile apps. We power over 300M+ people's conversations every month and we are working with the leading customers such as DoorDash, Reddit, Yahoo!, PayPal, Walgreens, and have raised $220M+ in total funding from ICONIQ, Tiger Global, Meritech, Emergence, SoftBank Vision Fund, Steadfast, Shasta, and August.

Team Size:300
Location:San Mateo, CA
Brandon Jeon
Brandon Jeon
Head of Trust and Safety
Harry Kim
Harry Kim
John S. Kim
John S. Kim