A lightweight C++17 Distributed Hash Table implementation.
OpenDHT provides an easy to use distributed in-memory data store. Every node in the network can read and write values to the store. Values are distributed over the network, with redundancy.
- Lightweight and scalable, designed for large networks and small devices
- High resilience to network disruption
- Public key cryptography layer providing optional data signature and encryption (using GnuTLS)
- IPv4 and IPv6 support
- Clean and powerful C++17 map API
- Bindings for C, Rust & Python 3
- REST API with optional HTTP client+server with push notification support
See the wiki: https://github.com/savoirfairelinux/opendht/wiki
You can help contributing to the public network by running a stable node with a public IP address. https://github.com/savoirfairelinux/opendht/wiki/Running-a-node-with-dhtnode
Build instructions: https://github.com/savoirfairelinux/opendht/wiki/Build-the-library
The tools directory includes simple example programs :
dhtnode, a command line tool, allowing to run a DHT node and perform operations supported by the library (get, put etc.) with text values.dhtchat, a very simple IM client working over the dht.
Example program launching a DHT node, connecting to the network and performing some basic operations:
#include <opendht.h>
#include <vector>
int main()
{
dht::DhtRunner node;
// Launch a dht node on a new thread, using a
// generated RSA key pair, and listen on port 4222.
node.run(4222, dht::crypto::generateIdentity(), true);
// Join the network through any running node,
// here using a known bootstrap node.
node.bootstrap("bootstrap.jami.net", "4222");
// put some data on the dht
std::vector<uint8_t> some_data(5, 10);
node.put("unique_key", some_data);
// put some data on the dht, signed with our generated private key
node.putSigned("unique_key_42", some_data);
// get data from the dht
node.get("other_unique_key", [](const std::vector<std::shared_ptr<dht::Value>>& values) {
// Callback called when values are found
for (const auto& value : values)
std::cout << "Found value: " << *value << std::endl;
return true; // return false to stop the search
});
// wait for dht threads to end
node.join();
return 0;
}import opendht as dht
node = dht.DhtRunner()
node.run()
# Join the network through any running node,
# here using a known bootstrap node.
node.bootstrap("bootstrap.jami.net", "4222")
# blocking call (provide callback arguments to make the call non-blocking)
node.put(dht.InfoHash.get("unique_key"), dht.Value(b'some binary data'))
results = node.get(dht.InfoHash.get("unique_key"))
for r in results:
print(r)- msgpack-c 1.2+, used for data serialization.
- GnuTLS 3.3+, used for cryptographic operations.
- Nettle 2.4+, a GnuTLS dependency for crypto.
- {fmt} 9.0+, for log formatting.
- (optional) restinio used for the REST API.
- (optional) llhttp used for the REST API.
- (optional) jsoncpp 1.7.4-3+, used for the REST API.
- Build tested with GCC 7+ (GNU/Linux, Windows with MinGW), Clang/LLVM (GNU/Linux, Android, macOS, iOS).
- Build tested with Microsoft Visual Studio 2019, 2022
IRC: join us on Libera.chat at #opendht.
Copyright (C) 2014-2025 Savoir-faire Linux Inc.
OpenDHT is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
See COPYING or https://www.gnu.org/licenses/gpl-3.0.en.html for the full GPLv3 license.
This project was originally based on https://github.com/jech/dht by Juliusz Chroboczek. It is independent from another (now extinct) project called OpenDHT (Sean Rhea. Ph.D. Thesis, 2005).
