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Quack: Turn DuckDB
into a client-server database

The Quack protocol unlocks multi-client access for DuckDB,
turning it into a general-purpose database system

Read the announcement Get started

Quack protocol

Client-server access · Beta release

Protocol reference
Client-server setup

Quack allows two DuckDB processes to talk to each other over the network, enabling a client-server setup (and more). The Quack protocol supports the full DuckDB feature set.

Set up Quack
Optimized for performance

We designed the Quack protocol for performance. We minimized the number of round trips, and ensured that the protocol can handle both small updates and large batches of changes.

See the benchmarks

Introducing Quack

Hannes Mühleisen introduced Quack at AI Council 2026.
Watch his talk, the “Super-Secret Next Big Thing for DuckDB”.

Thumbnail: Introducing Quack

Architecture

Clients

DuckDB client + Quack extension 
SELECT * FROM orders LIMIT 5;
┌──────┬───────────┬─────────┐
│  id  │  product  │  total  │
│   1  │  widget   │  42.00  │
└──────┴───────────┴─────────┘
DuckDB client + Quack extension 
INSERT INTO orders VALUES
    (3, 'tool', 29.99);
1 row inserted.
quack:
quack:

Server

DuckDB server + Quack extension 
CALL quack_serve();
  • listening on port 9494
  • 2 active connections
  • catalog: my_database.duckdb
read/write

Storage

  • my_database.duckdb
  • 128 MB · last write 0.3s
TABLES VIEWS ACID TRANSACTIONS PRIMARY KEYS INDEXES

Try Quack today

Install and configure Quack in seconds

More deployment options

Step 1

Install DuckDB 

curl https://install.duckdb.org | bash

Step 2

Launch Quack on the server 

CALL quack_serve(
    'quack:localhost',
    token = 'super_secret'
);

CREATE TABLE hello AS
    FROM VALUES ('world') v(s);

Step 3

Connect from the client 

CREATE SECRET (
    TYPE quack,
    TOKEN 'super_secret'
);

ATTACH 'quack:localhost' AS remote;
FROM remote.hello;

Frequently asked questions

What is Quack?

Quack allows DuckDB to connect to a DuckDB server through the quack: protocol. You can think of Quack as a Remote Procedure Call (RPC) protocol for DuckDB. Quack enables DuckDB instances to talk to each other, effectively turning DuckDB into a client-server database management system, where both the client and the server are DuckDB instances.

Why is it called Quack?

Mallard ducks communicate by quacking, so it's only fair that DuckDB instances communicate through the protocol quack.

When should I use Quack?

Quack can be beneficial in a number of scenarios, including the following:

  • You need concurrent read-write access to the same DuckDB database.
  • Your data is on a server and you want to move the computation as close to the data as possible.
  • You have a powerful server that can process the data but would like to see the results on your local computer.
  • And many more – we are excited to see what the community comes up with.

Can I use DuckDB with Quack for transactional (OLTP) workloads?

Yes. DuckDB with Quack can handle a few thousand writes per second on a server with 8 CPUs and 32 GB RAM. See the benchmarks in our announcement blog post.

Can I still run DuckDB as an in-process database?

Yes, DuckDB as an in-process database will continue working just as it did before, and we will treat the in-process deployment model as a first-class citizen in the DuckDB ecosystem.

More FAQs

Quack in the DuckDB ecosystem

Client-server DuckDB

Quack turns DuckDB into a client-server database for multi-writer and remote access.

Read the docs
DuckLake server

Quack supports querying DuckLake and other data lake formats.

Explore DuckLake
Community extensions

Quack works with all DuckDB extensions, including the Community Extension ecosystem.

Browse extensions