What tech stack does ClickHouse use?

The ClickHouse database engine is written in C++ — a 1.5-million-line codebase developed and performance-tuned since 2009. The engine achieves its sub-millisecond query performance through a columnar storage format, SIMD CPU instruction exploitation, a vectorized query execution pipeline, and aggressive compression using LZ4 and ZSTD. CTO Alexey Milovidov gave a talk titled 'ClickHouse's C++ and Rust Journey' at FOSDEM 2026, making clear the team is incrementally integrating Rust into specific isolated modules — starting with cryptographic hashing, CLI improvements, and alternative query engine components — but has no plans for a full rewrite, explicitly valuing C++ maturity and performance for the core.

Cloud platform backend services (API layers, control plane, orchestration) are written in Go, Python, and TypeScript/Node.js, consistent with modern cloud infrastructure patterns where each service is selected for the right performance and productivity tradeoff. ClickHouse Cloud runs on all three major hyperscalers — AWS, GCP, and Azure — with Kubernetes managing container orchestration, service scheduling, and automatic scale-to-zero. Storage and compute are separated: data lives in S3-compatible object storage (with cloud-specific variants per hyperscaler) while compute is ephemeral, enabling the consumption pricing model. Bring Your Own Cloud (BYOC) deployments on AWS allow regulated enterprises to keep data within their own VPC while ClickHouse manages the control plane.

The PeerDB acquisition (July 2024) added change data capture capabilities for PostgreSQL, and the HyperDX acquisition (March 2025) added an OpenTelemetry-native observability backend that became the foundation of ClickStack. These are both built on ClickHouse as their underlying store, adding to the company's self-referential infrastructure pattern.

The ClickHouse Cloud console and data visualization interfaces are built with React and TypeScript, confirmed by job postings on Greenhouse that explicitly require React and TypeScript experience for frontend engineering roles. The console interfaces with ClickHouse's native HTTP protocol and SQL API, and job descriptions reference data-oriented visualization components consistent with building query result displays, dashboards, and schema explorers.

For internal data infrastructure, ClickHouse almost certainly uses its own database for product analytics, usage telemetry, and billing metrics — a pattern common among analytics-native companies. The Langfuse LLM observability platform (acquired January 2026) uses ClickHouse as its backend store, confirming deep self-use. Apache Kafka or compatible streaming systems (Redpanda, Confluent) appear in ClickHouse integration documentation and job descriptions, indicating their use in the data ingest pipeline for the cloud platform. The PeerDB CDC integration and the new Managed PostgreSQL service (built with Ubicloud) both deepen PostgreSQL as a technology in the stack.

On the GTM side, Salesforce is the most probable CRM given CRO Kevin Egan's deep Salesforce background (ten years at Salesforce helping drive global enterprise growth) and the enterprise sales motion ClickHouse is building. Greenhouse is the confirmed ATS — all job postings are publicly hosted at job-boards.greenhouse.io/clickhouse. Slack is the stated internal communication platform. Langfuse is embedded in the product for LLM observability, and ClickStack (formerly HyperDX) serves as the company's own infrastructure observability layer.

ClickHouse's C++/Rust/Go engineering culture signals a high-performance, systems-engineering-first organization that values technical rigor over convenience. Vendors pitching to the engineering organization should lead with performance benchmarks, open-source credentials, API-first integrations, and documented case studies with comparable infrastructure companies — not product marketing slides. The multi-cloud Kubernetes infrastructure creates demand for cloud-native security (CNAPP, secrets management, KSPM), Kubernetes-native observability, and multi-cloud cost management tooling.

The confirmed Salesforce CRM environment is significant for any revenue-side vendor. Sales engagement, conversation intelligence, CPQ, revenue forecasting, and deal desk tooling that integrates deeply with Salesforce is immediately relevant as Kevin Egan builds out an enterprise sales motion from the ground up. The Greenhouse ATS is the confirmed entry point for HR technology vendors — compensation management, HRIS, learning and development, and employee engagement platforms should frame pitches around Greenhouse integration and the company's rapid headcount growth (60%+ YoY).

For competing data infrastructure vendors, ClickHouse's open CostBench benchmark (launched May 2026) and its published ClickHouse vs. Snowflake benchmark are the technical materials to study. ClickHouse wins on cost-per-query at high concurrency and real-time ingest scenarios; it is more complex to operate self-hosted than fully managed competitors, and StarRocks claims favorable benchmarks on denormalized table join workloads. Competitors should engage on integration ecosystem breadth, multi-model capabilities, and governance features where ClickHouse's specialized columnar engine has less depth.