Sr. Software Development Engineer, Annapurna Labs

AWS Networking builds the infrastructure that powers every customer workload in the cloud. ENA Express is a next-generation EC2 networking feature that leverages the Scalable Reliable Datagram (SRD) protocol — developed by AWS — to deliver industry-leading networking performance: dramatically lower tail latency, higher bandwidth utilization, and consistent packet delivery at scale.We are looking for a Senior Software Development Engineer to join the ENA Express team. You will design, build, and own features across the full ENA Express software stack: Firmware on the Nitro-Card, user-space libraries, control plane components, and the performance analytics systems that help our customers get the most out of their network. This is high-ownership work — your code runs on a fleet of millions of EC2 instances, supporting customers who demand the absolute best from their network, including HPC clusters, large-scale ML training, financial services, and other latency-critical applications.Key job responsibilities• Design and develop features across the AWS Networking software stack on Nitro Cards.• Deep-dive into ENA Express and the underlying SRD protocol and L3/L4 networking to optimize packet delivery, reduce tail latency, and improve bandwidth utilization.• Collaborate with hardware and firmware partners to define software/hardware interfaces and surface programmable capabilities to the software layer• Partner with EC2 platform and service teams to integrate ENA Express features into the broader AWS networking ecosystem• Mentor junior and mid-level engineers, lead design reviews, and champion engineering best practices across the team• Drive operational excellence: build observability, contribute to on-call health, and lead incident response and post-mortemsAbout the teamWe are a team of senior engineers with deep expertise in systems software, networking protocols, and EC2 infrastructure. Our work spans the full stack — from the Firmware on the driver Card, and NIC driver layer up through the EC2 control plane — and we collaborate closely with hardware, firmware, and platform partners. We care deeply about technical craft, operational quality, and each other’s growth.Diverse ExperiencesAmazon values diverse experiences. Even if you do not meet all of the preferred qualifications and skills listed in the job description, we encourage candidates to apply. If your career is just starting, hasn’t followed a traditional path, or includes alternative experiences, don’t let it stop you from applying.Work/Life BalanceWe value work-life harmony. Achieving success at work should never come at the expense of sacrifices at home, which is why we strive for flexibility as part of our working culture. When we feel supported in the workplace and at home, there’s nothing we can’t achieve in the cloud.Inclusive Team CultureHere at AWS, it’s in our nature to learn and be curious. Our employee-led affinity groups foster a culture of inclusion that empower us to be proud of our differences. Mentorship and Career GrowthWe’re continuously raising our performance bar as we strive to become Earth’s Best Employer. That’s why you’ll find endless knowledge-sharing, mentorship and other career-advancing resources here to help you develop into a better-rounded professional.Basic qualifications- 5+ years of non-internship professional software development experience- Bachelor's degree in computer science or equivalent- Background in systems programming (C / C++) in performance-critical, production environmentsPreferred qualification - Experience in Linux and Networking protocols, or experience in Network protocols like DNS/DHCP/TCP and experience that includes strong analytical skills, attention to detail, and effective communication abilities- Experience with virtualization (Hypervisors, VMware, Xen), or experience in managing and troubleshooting network and experience in Network protocols like DNS/DHCP/TCP- Experience working with software teams to tightly define the HW/SW interface, including control/status registers and error handlingAmazon is an equal opportunity employer and does not discriminate on the basis of protected veteran status, disability, or other legally protected status.Los Angeles County applicants: Job duties for this position include: work safely and cooperatively with other employees, supervisors, and staff; adhere to standards of excellence despite stressful conditions; communicate effectively and respectfully with employees, supervisors, and staff to ensure exceptional customer service; and follow all federal, state, and local laws and Company policies. Criminal history may have a direct, adverse, and negative relationship with some of the material job duties of this position. These include the duties and responsibilities listed above, as well as the abilities to adhere to company policies, exercise sound judgment, effectively manage stress and work safely and respectfully with others, exhibit trustworthiness and professionalism, and safeguard business operations and the Company’s reputation. Pursuant to the Los Angeles County Fair Chance Ordinance, we will consider for employment qualified applicants with arrest and conviction records.Our inclusive culture empowers Amazonians to deliver the best results for our customers. If you have a disability and need a workplace accommodation or adjustment during the application and hiring process, including support for the interview or onboarding process, please visit for more information. If the country/region you’re applying in isn’t listed, please contact your Recruiting Partner.The base salary range for this position is listed below. Your Amazon package will include sign-on payments and restricted stock units (RSUs). Final compensation will be determined based on factors including experience, qualifications, and location. Amazon also offers comprehensive benefits including health insurance (medical, dental, vision, prescription, Basic Life & AD&D insurance and option for Supplemental life plans, EAP, Mental Health Support, Medical Advice Line, Flexible Spending Accounts, Adoption and Surrogacy Reimbursement coverage), 401(k) matching, paid time off, and parental leave. Learn more about our benefits at .USA, CA, Cupertino - 193,300.00 - 261,500.00 USD annually