QuestDB is a time-series database written in Java and C++ that is absurdly fast. We are talking millions of rows ingested per second fast. The founders built it because they were tired of Postgres and InfluxDB being too slow for high-frequency financial data. The result is a database that financial firms, IoT platforms, and monitoring tools use when every other database cannot keep up. Open source, 14,000 GitHub stars, and growing. The fastest database most developers have never heard of.
Founded
2014
HQ
London, UK
Total Raised
$23 million
Founder
Vlad Ilyushchenko, Nicolas Hourcard, Tanc Tamburo
Status
Private
Website
www.questdb.ioTHE ORIGIN STORY
Vlad Ilyushchenko was working in low-latency trading systems in the City of London when he realized that existing databases couldn't handle the volume and speed of financial market data. Tick data, order book data, sensor data, all needed to be ingested and queried in real-time.
In 2014, he started building QuestDB as a time-series database designed from scratch for maximum performance. Instead of building on top of existing storage engines, he wrote the core in C++ and Java with zero-GC (garbage collection) principles, meaning the database doesn't pause for memory cleanup.
WHAT THEY ACTUALLY DO
Open-source core with a managed cloud service. QuestDB is free to download and self-host.
QuestDB Cloud is the managed version that charges based on usage (compute, storage, and data ingestion).
The business model follows the familiar open-source-to-cloud playbook: attract developers with the free product, convert enterprises to the paid managed service.
THE PRODUCTS
QuestDB open-source database with millisecond-level query latency and million-row-per-second ingestion. QuestDB Cloud managed service.
SQL API compatible with PostgreSQL wire protocol. Built-in web console for querying and visualization.
HOW THEY GREW
Developer community first. QuestDB grew through GitHub, Hacker News posts, and word of mouth among developers who needed fast time-series processing.
Benchmark blog posts comparing QuestDB's performance to InfluxDB, TimescaleDB, and ClickHouse generated significant attention.
The SQL interface was a strategic choice. Unlike InfluxDB with its custom query language, QuestDB uses standard SQL with time-series extensions.
This lowered the learning curve for developers who already knew SQL.
THE HARD PART
Competing against well-funded time-series databases (InfluxDB, TimescaleDB, ClickHouse) with less capital. Each competitor has specific strengths and established user bases.
Monetization of open-source is the perennial challenge. Most users run the free version.
Converting them to the paid cloud service requires the cloud offering to be significantly easier than self-hosting.
MONEY TRAIL
Seed
2020 · Led by Episode 1 Ventures
$2M raised
Series A
2022 · Led by Alexia Capital
$15M raised
WHO BACKED THEM
QuestDB raised $23 million from investors including Alexia Capital, Y Combinator, and Episode 1 Ventures.
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