Senior Engineer, Infrastructure

ThredUp is transforming resale with technology. As a Senior Engineer, Infrastructure, you will design, build, and evolve core infrastructure with focus on database reliability, performance, and operability. You'll work with AWS, Kubernetes, Terraform, and lead cross-team initiatives.

• Lead or significantly contribute to medium-to-large infrastructure projects crossing multiple engineering teams.
• Serve as a domain expert in cloud infrastructure, orchestration, observability, and platform automation, and as the team’s primary owner of database reliability and performance.
• Ensure ThredUP’s infrastructure evolves to support scale, resilience, and developer productivity.
• Architect and implement highly available, secure, and cost-efficient cloud infrastructure using AWS, Kubernetes (EKS), and Terraform.
• Drive improvements in CI/CD, observability, networking, and security across the platform.
• Provide high-quality, impactful technical contributions across infrastructure projects, setting engineering standards.
• Participate in and lead design reviews, providing constructive feedback and driving engineering excellence.
• Operate, monitor, and tune AWS Aurora and RDS clusters (MySQL and PostgreSQL), including parameter groups, maintenance, minor/major upgrades, and point-in-time restores.
• Own HA and replication behavior: respond to failovers, work with cluster vs. instance endpoints, and run the checks required before promoting a reader to writer.
• Triage and resolve CPU/IO/locking/replication incidents; analyze slow query logs and EXPLAIN/EXPLAIN ANALYZE plans to produce immediate mitigations and long-term fixes.
• Plan and execute zero-downtime schema changes with safe rollback paths (online DDL, gh-ost / pt-online-schema-change, pg_repack, logical replication, trigger-based backfills).
• Partner with application teams to remove N+1 queries, tune indexes, and rewrite inefficient predicates; design partitioning and retention for high-write tables.
• Design, execute, and regularly validate backup and disaster-recovery procedures.
• Act as an expert in infrastructure design, performance, and operations across multiple systems and services.
• Promote shared ownership of infrastructure by driving documentation, tooling, and process improvements.
• Monitor and optimize system performance, ensuring reliability while protecting teams from burnout.
• Build relationships with engineering teams, product managers, and cross-functional partners to ensure infrastructure supports company goals.
• Contribute to defining strategic technical direction, setting infrastructure roadmaps, and guiding prioritization.
• Advocate for best practices in reliability, security, and cost management.
• Ensure knowledge is shared within the team, reducing single points of failure.

• 6+ years of relevant industry experience with a Bachelor’s degree in Computer Science, Engineering, or related field (or equivalent experience).
• Hands-on experience operating MySQL and PostgreSQL in production (Aurora/RDS preferred), including indexing strategies, transactions, locking/MVCC, and performance tuning.
• Demonstrated experience performing zero-downtime schema changes with safe rollbacks.
• Proven track record of designing and scaling infrastructure for distributed, service-oriented architectures.
• Expertise in AWS (EKS, RDS, IAM, cost optimization).
• Proficiency with Kubernetes and Terraform.
• Experience with CI/CD pipelines and practices (e.g., Jenkins, GitHub Actions, or ArgoCD – one or more).
• Experience with observability and monitoring tooling (Datadog, CloudWatch, or similar), including slow query and error log analysis.
• Ability to diagnose connectivity issues affecting database access (security groups, VPC routes/TGW, VPN, DNS).
• Scripting and automation skills (Python, Bash, or similar).
• Excellent communication and collaboration skills.
• Experience with Teleport (or similar DB proxying) and IAM DB authentication.
• Experience tuning Postgres autovacuum and designing partition-based retention policies.
• Terraform/Terragrunt module design for RDS/Aurora clusters and snapshot restores.
• Familiarity with service mesh (Istio) and edge/WAF tooling (Cloudflare).
• Familiarity with data infrastructure (Airflow, Databricks) and messaging/streaming systems (RabbitMQ, Kafka, DynamoDB, MongoDB).
• Knowledge of network security, vulnerability management, and incident response best practices.
• Experience with Rollbar or centralized logging pipelines.
• Experience in fintech, testing automation, and/or compliance-heavy environments (GDPR, SOC2).
• Prior leadership in scaling platforms for e-commerce or high-growth startups.

• Monthly allowance for insurance/education ($200 gross).
• 50% paid sabbatical after 3 year anniversary.
• Paid parental leave for new mothers and fathers.
• IT Kit.