kdb+ is a column-based time-series database from KX, queried with q and long used for tick data. KDB-X is its next generation, and it adds Python and SQL routes. Most alternatives replace the database. If your real need is a backtest, the alternative may be a different kind of tool.
Why teams look for kdb+ alternatives
- They want SQL, or Python, and not q.
- They want an open-source licence or a published price.
- Their data is too large for the free KDB-X Community Edition, which is limited to 16 GB of memory for q.
- They use it mainly to backtest, and have to write the fills and costs themselves.
kdb+ alternatives compared
Details below were checked against each project's own pages in November 2026.
| Tool | Type | Query language | Best for | Licence |
|---|---|---|---|---|
| QuestDB | Time-series database | SQL | Market data with SQL | Apache 2.0, paid enterprise edition |
| ClickHouse | Columnar database | SQL | General analytics at scale | Apache 2.0, paid cloud and enterprise |
| DolphinDB | Time-series database | Own scripting language | Data and order-book backtests in one system | Proprietary, free community edition with limits |
| TimescaleDB | PostgreSQL extension | SQL | Teams already on PostgreSQL | Apache 2.0 core, Timescale License for other features |
| ArcticDB | Dataframe database | Python | Python research teams | Business Source License |
| OneTick | Data and analytics platform | SQL, Python | Managed data, transaction cost analysis, surveillance | Commercial |
| Reamer Research | Backtesting engine, not a database | Python, C++ or C | Backtests of strategies on bars | $1,800 per seat per year |
Databases
- QuestDB is open source and names capital markets as a main use. It has SQL, nanosecond timestamps, order book analytics and materialized views from ticks to OHLCV bars. High availability needs the paid edition.
- ClickHouse is a general columnar database, so market data functions and conventions are yours to add.
- DolphinDB has the same shape as kdb+: a database with its own language. It adds a backtest plugin with a matching-engine simulator. See How does Reamer Research compare with DolphinDB?
- TimescaleDB extends PostgreSQL, so existing tools and skills carry over.
- ArcticDB from Man Group stores dataframes and suits Python teams. Its licence is free for non-commercial use, and firms need a commercial licence.
- OneTick is now from KX too, so it is not a change of vendor. See What are the best OneTick alternatives in 2026?
If you use kdb+ to backtest
A database computes on your data. It does not decide how orders fill. KX's own October 2026 tutorial leaves out commission, spread and slippage, and tells the reader to add them.
Reamer Research is an engine for that part, for strategies on OHLCV bars. Bid and ask, spread, slippage, commission, swap, margin and order lifetimes are in place under a public execution specification. It stores no data, so you can keep kdb+ or any database here and pass in bars. It works on bars, not ticks. See How does Reamer Research compare with kdb+?
How to choose
| If you want | Look at |
|---|---|
| Very large tick data, with q skills on the team | Stay on kdb+ or KDB-X |
| Open source with SQL, for market data | QuestDB |
| General analytics at scale | ClickHouse |
| A database and order-book backtests in one system | DolphinDB |
| To stay on PostgreSQL | TimescaleDB |
| Modelled fills and costs for strategies on bars | Reamer Research, with any database |
See Who are Reamer Research and Reamer Server for? Reamer Research has a $225 30-day trial; see pricing.