Software Engineer- Core System Libraries

San Francisco, CA

Who We Are:

The Core System Libraries team provides key distributed systems libraries which enable engineers to build reliable and efficient Twitter-scale services. Ensuring the resiliency of Twitter’s core libraries directly impacts the lives of our users and the success of our business.

What You’ll Do:

As an engineer on our team, you will face some of the hardest problems in modern software engineering. The scale at which your systems will operate require not only producing and using highly-performant algorithms and data structures, but also solving complex problems involving emergent behavior of distributed systems. You will have the opportunity to work on some of the world’s most highly-scaled distributed systems. Our core infrastructure receives hundreds of millions of tweets per day and serves tens of billions of API requests, while meeting stringent availability requirements. You and your fellow engineers will power the core libraries relied on every single day by Twitter’s users. In addition, many of our team's libraries are open-source including Finagle, Finatra, and others.

Who You Are:

  • You want to be part of a community of the most talented, forward-thinking engineers in the industry.
  • You are passionate about continually redefining the limits of scale and performance.
  • You have strong computer science fundamentals.

Ideally, you would have experience with:

  • Distributed systems, performance analysis, web infrastructure, and/or large-scale data processing
  • JVM development, including asynchronous I/O, concurrency, and the Java memory model
  • Open-source contributions


  • BS, MS, or PhD in Computer Science, or equivalent work experience
  • Experience with Java, Scala, or another modern systems language
  • Occasional on-call support during non-standard business hours

We are committed to an inclusive and diverse Twitter. Twitter is an equal opportunity employer. We do not discriminate based on race, ethnicity, color, ancestry, national origin, religion, sex, sexual orientation, gender identity, age, disability, veteran status, genetic information, marital status or any other legally protected status.

San Francisco applicants: pursuant to the San Francisco Fair Chance Ordinance, we will consider for employment qualified applicants with arrest and conviction records.

Engineering Hiring Process

Step 1

Once your application is received, a recruiter will reach out pending your qualifications are a match for the role.

Step 2

If your background is a match, you may have 1-2 technical phone interviews or be given the chance to provide a work sample depending on the role.

Step 3

If the phone interviews go well or your work sample is strong, the final step includes interviews with 5-6 people held onsite in our office.


Personal Information

This field is required.
This field is required.
This field is required.
This field is required.
Required field. PDFs only; max file size is 1MB.
Required field. PDFs only; max file size is 1MB.

U.S. Equal Opportunity Employment Information  (Completion is Voluntary)

At Twitter, we have a bold aspiration to reach every person on the planet. We believe that goal is more attainable with a team that understands and represents different cultures and backgrounds and we are committed to an inclusive and diverse Twitter.

This is where you come in! Please take a few minutes to provide us with your information. You are not required to provide this information and you may select “Decline to Disclose”. Your decision to provide information (or not) will not affect your employment or opportunities at Twitter.

Twitter is an equal opportunity employer. We do not discriminate based on race, color, ethnicity, ancestry, national origin, religion, sex, gender, gender identity, gender expression, sexual orientation, age, disability, veteran status, genetic information, marital status or any legally protected status.

You can view the ‘EEO is the Law’ poster here.

Twitter does not accept any unsolicited resumes from recruiting agencies and will not pay fees associated with any such resumes. Agencies, please do not send resumes to any Twitter location, employee, or email address.

Twitter, Inc. is committed to working with and providing access and reasonable accommodations to applicants with physical or mental disabilities. If you need an accommodation in order to apply for open job opportunities, please submit a description of your accommodation request to This email is only for accommodation requests related to the application process.

Twitter cares about your privacy and protecting your data.  Please click the privacy policy link and acknowledge you have read and understood how Twitter treats your privacy and your data.  

Would you like to receive email communication from Twitter about career opportunities? You may unsubscribe at any time.
Applicant Data - You have a choice. Can we keep your personal data for both the job you are applying for and any other Twitter jobs that we feel you may be a match for? If you choose yes we will retain your personal data for a period of twelve months to consider you for other job opportunities at Twitter.
Analytics - May we use personal data from your resume and application to analyze and improve the Twitter hiring experience.
Thanks for applying!
Submission failed. Please make sure all fields are correctly formatted.

Don't see the right fit?

Check out other opportunities at Twitter.