$ echo "Hello, world. I'm"
// Software Engineer
Backend engineer at DoorDash, working on Ads & Promotions. I build event-driven systems on Kafka, distributed rate limiting on Redis + Cassandra, and the CI/CD guardrails that keep them honest at production scale.
I'm John — backend engineer on the Ads & Promotions team at DoorDash. I spend my days decoupling synchronous code paths into Kafka pipelines, designing rate-limiting frameworks on top of Redis and Cassandra, and pushing deployments through Spinnaker canaries with automated regression detection.
Before that I interned twice at DoorDash on Supply & Demand and Consumer Android, and graduated from Connecticut College with high honors in CS and Statistics & Data Science. I care about idempotency, low-latency tail behavior, and writing the kind of services on-call engineers don't dread.
$ cat whoami.json { "name": "John Mwai", "role": "Software Engineer @ DoorDash", "team": "Ads & Promotions", "focus": ["kafka", "rate-limiting", "k8s"], "langs": ["java", "kotlin", "python", "go"], "based": "new york, ny", "alma": "connecticut college '23" } $ uptime since aug 2023 · 6+ infra projects shipped · 2 mentees
$ git log --author="john" --oneline
DoorDash · New York, NY
Owning event-driven infrastructure for promotion endpoints serving production traffic. Shipped 6+ complex projects spanning Kafka pipelines, distributed rate limiting, multi-cell scheduling, zero-downtime migrations, and CI/CD guardrails. Mentor 2 junior engineers on distributed-systems patterns and interview candidates for the team.
DoorDash · San Francisco, CA
Built a hotspot prediction pipeline on Uber H3: snapped real-time and historical order density onto hex cells, then ran DBSCAN over those hexes to surface high-demand regions for Dasher allocation. Kotlin pipelines and Python batch jobs refreshed the hex-level clusters.
DoorDash · San Francisco, CA
Redesigned the Android in-app rating flow into a shorter post-delivery path, then A/B tested an incremental rollout. Qualitatively, the new flow cut friction after delivery. Quantitatively, it reached 10M+ users and lifted rating-flow engagement 4× versus control.
Connecticut College · New London, CT
GPA 3.85 / 4.00 (Major 3.93). Dean's High Honors, Dean's Scholarship.
Always happy to chat about distributed systems, event-driven architecture, or career advice for new grads heading into infra. LinkedIn is the fastest way through.