About the role

Role overview

As a Senior Site Reliability Engineer for Thunderbird (Mozilla), you will help build and maintain the operational infrastructure behind privacy-focused, open-source products. You’ll design CI/CD pipelines, lead reliability improvements, and support production operations with a strong incident response and troubleshooting mindset.

Responsibilities

Establish and maintain the infrastructure and operational systems used daily by Thunderbird users and teams.
Design and develop CI/CD systems for MZLA websites, services, and release workflows.
Diagnose and debug production incidents and drive improvements to enhance reliability.
Operate and evolve an EKS-based Kubernetes platform, including service migrations and reliability initiatives.
Partner with software engineers and platform stakeholders to improve platform reliability and operational efficiency.

Requirements

7+ years in infrastructure, platform engineering, or SRE roles, including hands-on production Kubernetes operations (workloads, troubleshooting, cluster management).
Hands-on infrastructure-as-code on AWS using Terraform, OpenTofu, or Pulumi.
Security awareness: identity, least privilege, secrets hygiene, and network controls.
Experience with GitOps workflows (Argo CD or Flux).
Strong ownership mindset: proactively identify issues, drive work to completion, and communicate risks early.
Excellent async written communication with distributed teams; comfortable working with stakeholders.
Consistent overlap with Pacific Time (PT) working hours (remote role).

Nice-to-haves

Familiarity with Keycloak or similar identity platforms (OIDC, SAML, federation).
Knowledge of email protocols and/or experience operating email infrastructure (SMTP, IMAP).
Prior work in or alongside an open-source community.
Ability to learn and evaluate emerging/AI-enabled tools to improve processes.
Additional language proficiency (French, German, Japanese, or others) beyond English.

About Mozilla

Mozilla is a global technology company known for its open-source software and commitment to privacy and the open web. The role is specifically within the Thunderbird project, an open-source email client focused on privacy and user ownership.