developer-apis enterprise-software telephony
Mountain View, CA

Sr. Software Engineer - Programmable Voice - Media


Because you belong at Twilio

The Who, What, Where and Why

Twilio is growing rapidly and seeking a Sr. Software Engineer to design, develop and operate our media edge for Programmable Voice.  This role includes services from Carrier, SIP, WebRTC and Mobile edge to intelligent systems such as Text-to-Speech, Speech-to-Text, Answering Machine Detection, to Real Time Streaming and Transcriptions.  You will collaborate with Product Managers, Architects, and Engineering leaders to define, architect and build new customer-facing voice features. This engineer will own, operate and maintain their teams’ services in a distributed production environment, employing Agile methodologies to continuously deliver value to customers.


  • Minimum 5 years hands-on experience developing media processing systems, and with some specific focus on voice quality issues in a network environment.  You must have direct experience writing optimized C/C++ code on multiple platforms, including development experience in a real-time and multi-threaded software environment.
  • Strong IP networking background, including an understanding of end-to-end network performance issues as they relate to media quality, including techniques employed to ensure high quality under challenging conditions.
  • Extensive knowledge and experience working with a variety of media standards including G.711 (PCMU/PCMA) and Opus, and as examples  You must be able to compare and contrast amongst them, and be able to explain performance and quality metrics, and their behavior under various conditions.
  • Extensive experience with real-time protocols including SIP/RTP/RTCP
  • Exposure to WebRTC client and server implementations is a plus
  • Prior experience with building microservices in Java (e.g. dropwizard)
  • General understanding of HTTP, WebSocket, REST APIs and relevant use cases
  • Bachelor's degree (or equivalent) and 5+ years of experience with software development lifecycle and processes


As a member of our real-time communications team, you will implement media processing capabilities for our programmable real-time voice services using Java and C++.  You will be focused on developing services for streaming, routing, mixing, transcoding and recording. To take it to scale you will focus on solving density, latency and media quality challenges that exist in a virtualized cloud environment.

  • Collaborate with Product Managers, Architects and Engineering leaders to define, architect and develop media processing capabilities.  
  • Drive quality by writing unit, functional, load and performance tests specific to media processing functions.  Employ Agile methodologies to continuously deliver value to customers.
  • Contribute to the definition and development an R&D roadmap for media processing capabilities, including continuous evaluation of industry standards, techniques, tools and trends.  Ensure Twilio develops and maintains an industry competitive edge.
  • Excel as an engineer and be a productive member of the team where leadership is a behavioral trait, not a title.  Lead architecture, design and code reviews as well as mentor junior engineers.


Twilio’s Programmable Voice team handles millions of calls every day, connecting callers, carriers, and companies across the globe. We solve complex problems at scale with next-generation telecommunications infrastructure. We craft APIs that are simple enough for any developer to use, yet robust enough to power the world’s most demanding voice applications.


This position will be located in our beautiful office in Mountain View office at 399 El Camino Real. You will enjoy our incredible perks: catered meals, snacks, game room, ergonomic desks, massages, Wednesday Night dinners, bi-weekly All Hands and more. What you will also get to experience is a company that believes in small teams for maximum impact; that strives to balance work and home life, that understands that this is a marathon, not a sprint; that continuously and purposefully builds an inclusive culture where everyone is able to do and be the best version of themselves. We seek people who naturally demonstrate our values, who are challenged by problems, empower others to thrive, people who can draw the owl and not be beholden to one playbook.

About us:

More than 2 million developers around the world have used Twilio to unlock the magic of communications to improve any human experience. Twilio has democratized communications channels like voice, text, chat, and video by virtualizing the world’s telecommunications infrastructure through APIs that are simple enough for any developer to use, yet robust enough to power the world’s most demanding applications. By making communications a part of every software developer's toolkit, Twilio is enabling innovators across every industry — from emerging leaders to the world’s largest organizations — to reinvent how companies engage with their customers. Founded in 2008, Twilio has over 1,000 employees, with headquarters in San Francisco and other offices in Berlin, Bogotá, Dublin, Hong Kong, London, Madrid, Mountain View, Munich, New York City, Prague, Singapore and Tallinn.

Twilio is proud to be an equal opportunity workplace and is an affirmative action employer. We are committed to equal opportunity regardless of race, color, ancestry, religion, gender, gender identity, parental or pregnancy status, national origin, sexual orientation, age, citizenship, marital status, disability, or Veteran status and operate in compliance with the San Francisco Fair Chance Ordinance.

Work with this stack