MongoDB Performance Engineer

About the Role

We are seeking a hands-on Sr MongoDB Performance Engineer to own the throughput, latency, scalability, and operational reliability of our MongoDB landscape. This is a database engineering role focused on making MongoDB fast, predictable, and cost-efficient at scale.

Responsibilities

• Profile and optimize slow queries and aggregation pipelines using explain plans, the database profiler, and log analysis.
• Design, review, and rationalize indexes (compound, partial, wildcard, TTL, text, geospatial) applying the Equality, Sort, Range (ESR) rule; eliminate unused and redundant indexes that inflate write cost and cache pressure.
• Tune the WiredTiger storage engine: internal cache sizing, eviction and checkpoint behavior, compression, and journaling, balanced against filesystem cache.
• Operate and scale sharded clusters: balancer management, chunk/range distribution, jumbo-chunk remediation, and resharding (on modern versions).
• Own backup/restore and Point-In-Time Recovery (PITR) strategy, plus rolling upgrades and patching with zero or minimal downtime.
• Right-size EC2 instances and EBS volumes (IOPS and throughput provisioning); on Kubernetes, own StatefulSet storage class, resource requests/limits, anti-affinity, and cache sizing against container memory limits.
• Partner with application teams on data modeling; review schema changes; publish standards, runbooks, and capacity guidance.

Requirements

• Expert in MongoDB with strong experience in performance tuning.
• Fluent in the aggregation framework, indexing strategy, and read/write/read-concern semantics.
• Strong explain-plan and profiler-driven query optimization.
• Deep knowledge of WiredTiger internals: cache, eviction, checkpoints, journal, compression, and document-level concurrency.
• Experience with replication and sharding operations at scale, including shard-key design trade-offs.
• Strong scripting skills for automation (Python).
• Proven experience tuning specific clusters, queries, indexes, and schemas.
• Experience designing sharding strategy and shard keys; planning resharding and zone strategy.
• Experience operating and monitoring existing sharded clusters; running balancer and fixing hot chunks.

Nice to Have

• MongoDB certification.
• Experience with Kubernetes operator for stateful MongoDB.
• Infrastructure-as-Code (Terraform/Ansible).