Teams using Cassandra database
Datadog
HQ: United States Java, Golang, JavaScript... Terraform, Datadog, Elasticsearch... Redis, Cassandra, PostgreSQL...️ AWS
Grafana Labs
HQ: United States Golang, Python, Ruby... React, JavaScript, TypeScript... Grafana, Kubernetes, Kafka... Cassandra, InfluxDB, MySQL...️ Azure, AWS, GCP...
SoftwareMill
HQ: Poland Scala, Java, Spring Framework... JavaScript, TypeScript, React... Kafka MongoDB, Cassandra️ AWS, GCP
Python 
Front-end 📊 Product/Management
JVM ☁️ DevOps
JavaScript BE 
Golang 🎨 UI/UX Design
📱 Mobile
PHP 
C#/.NET 
Ruby/RoR 🔨 Testing/QA