CMN Synapse is a free, open source indexer for the CMN network, built for developers and operators who want to run their own discovery service. It ingests signed manifests, records the spores and myceliums the network tracks, and answers discovery queries so people can find content without relying on one central index. The project is written in Rust and is currently at version v0.3.0.
Synapse also acts as the federated and resilience layer of CMN. Its documentation describes it as the network's search engine and backup layer, and instances sync with each other over Nostr. The latest code update landed on August 5, 2026, so the project is actively maintained. If you want to run a discovery node, keep reading. If you are looking for an app for everyday browsing, a Nostr client will serve you better.
What Is the CMN Network?
CMN is organized around signed manifests and sovereign domains. That points to a model where publishers keep control of their own material instead of depending on one central platform. The trade-off is that someone has to collect what exists, check where it came from, and make it searchable.
CMN Synapse fills that role. As the reference indexer, it shows how the network's indexing layer is meant to work. It ingests signed manifests, records spores and myceliums, and serves discovery queries. Think of the network as a large library with many owners: each owner keeps their own shelves, and the indexer builds the card catalog that lets readers find items across all of them.
The analogy has limits, but it explains why the project describes itself as both a search engine and a backup layer. Search needs a shared view of content, and resilience needs copies of that view in more than one place. Those two goals are the reason the indexer exists alongside the publishers themselves.
Who Should Run CMN Synapse?
CMN Synapse suits developers who build applications that query the CMN network. A local indexer gives your app a source of discovery results you control, instead of depending on an outside service for every lookup. Developers who want to study how signed manifests are processed will also find the open source Rust code useful.
Community operators form a second group. A team that cares about a particular set of CMN content might run an instance so its members can search a shared index. Because instances sync over Nostr, several operators can exchange data and keep one another's indexes useful. A small group might run a single instance on a home server or a rented machine.
The project is less suited to people who want a polished app for daily use. Expect to work from a terminal and configuration files, since that is how a reference indexer is typically run. If your goal is simply to read and post on Nostr, a client such as Gossip or Amethyst will serve you better.
How Federated Indexing Keeps Discovery Working
A single search index is a single point of failure. If it goes offline or its operator stops maintaining it, everyone relying on it loses discovery. Federation spreads that risk. Each Synapse instance holds its own copy of the index, and instances exchange data with one another, so the network does not depend on any one node staying online.
Nostr provides the messaging layer for this exchange. Instances share updates over Nostr rather than connecting to a central server, which fits the decentralized design of CMN. In practice, an instance that has been offline can refresh its view from peers once it reconnects.
Federation also has trade-offs. Each operator decides which peers to trust, so an index is only as reliable as the sources it syncs from. Results can differ between instances connected to different peers. Treat peer selection as an important decision, read the release notes when you update, and keep your copy current.
Key features
Signed Manifest Ingestion
Indexing of Spores and Myceliums
Discovery Queries
Instance Sync Over Nostr
Supported coins
Synapse's sync layer runs over Nostr, the network its documentation names for communication between instances. It is an indexer within the Nostr ecosystem, so it does not store, send or hold coins.
How to install CMN Synapse on Windows
- 1
Open the Official Repository
Go to the project's GitHub repository at https://github.com/cmnspore/cmn-synapse and open the Releases page. Look for v0.3.0 and check whether it includes a Windows build. Download only from the official website or its GitHub Releases page.
- 2
Verify the Download
Calculate the SHA-256 checksum with PowerShell using Get-FileHash -Algorithm SHA256, then compare the result with the value published on the release page. If a signature is provided, verify it too. Do not run a file whose checksum does not match.
- 3
Install or Build
If a Windows build is provided, extract it to a folder you choose and run it from there. If only source code is available, install the Rust toolchain with rustup and build the project with cargo, following the repository instructions. Rust is needed for the build step only, not to run the finished program.
-
Confirm the Installation
Run the help or version command described in the repository README to confirm the program starts. Note the version number so you can compare it with future releases when you update.
How to use CMN Synapse
Using CMN Synapse is mostly a matter of configuring a node and pointing your tools at it. The steps below follow the general flow of running a reference indexer.
- Read the README and configuration documentation in the repository before you start.
- Choose a data directory on a drive with enough free space for the index.
- Set the basic configuration, including which Nostr relays and peer instances the node should use.
- Start the indexer from a terminal and watch the first output for errors.
- Send discovery queries to the local instance from your application or script.
- Review logs regularly, and update to new releases after checking the release notes.
Pros & cons
- Free and open source, with the code published on GitHub
- Written in Rust, a language known for performance and memory safety
- Ingests signed manifests, so indexed entries can be traced to their sources
- Syncs across instances over Nostr rather than a single central server
- Recent code update in August 2026 shows active development
- Windows support is listed as likely rather than clearly confirmed, so check the Releases page first
- Aimed at developers and operators, not everyday users
- Version v0.3.0 suggests an early stage, so interfaces may change between releases
Is CMN Synapse safe?
CMN Synapse is an indexer, not a wallet or miner, so it does not hold your coins or keys. It still handles signed data and runs as a network-facing service, so treat it with care. Download only from the official GitHub repository, compare the SHA-256 checksum with the published value, and verify signatures when they are offered. Be cautious with mirrors, forks, or builds shared in chats, since a modified program could index or serve content you did not intend. The last code update on August 5, 2026 shows the project is current, but that does not replace your own verification. Check the latest version on the official website before you deploy it.
- Official source only. Download from github.com/cmnspore/cmn-synapse. Ignore ads and lookalike domains.
- Check the SHA-256. Compare the installer hash with the value the developer publishes before running it.
- Never share your seed phrase. No developer, support agent or website — including CryptApps — will ever ask for it.
Alternatives
Most programs in this group are Nostr clients. Amethyst, Coop, Gossip and Vega are for reading and posting, and Blockcore Notes is an installable web app for following people. NAK and Nostr Commander RS are command-line tools, so they are closer to CMN Synapse in how you work with them, but they focus on sending and querying Nostr events rather than indexing a separate network. Nostr VPN takes a different route, building a mesh VPN on Nostr signaling. CMN Synapse is an indexer for CMN, designed to run as a service that other tools can query.
Specifications
- Price
- Free
- Type
- Open source
- License
- —
- Latest version
- v0.3.0
- Last update
- 5 Aug 2026
- Windows support
- Likely (builds for Windows; check releases)
- Source code
- github.com/cmnspore/cmn-synapse
Frequently asked questions
Yes, CMN Synapse is free and open source, and its source code is published on GitHub. The main cost is the time and hardware needed to run an instance. Check the repository for license terms before you redistribute the software.
It is likely, since the project builds for Windows, but confirm it on the Releases page for v0.3.0 before you plan around it. If no Windows build is available, you can compile the Rust source code yourself after installing the toolchain.
It can be, if you take normal precautions. Download it from the official GitHub repository, compare the SHA-256 checksum with the published value, and verify any signature. Because it is an indexer rather than a wallet, it does not manage coins, but keep it updated because it runs as a network service.
An indexer collects and organizes network data so others can search it, while a client is the app a person uses to read and post. CMN Synapse plays the indexer role. Clients such as Gossip or Amethyst display content to people, while Synapse answers the queries that other tools send to it.
No, not if a ready-made build is available for your system. Rust is only needed if you compile the project from source, which means installing the toolchain with rustup and building with cargo. Rust is a build-time dependency, not a requirement for running the finished program.
Instances sync with each other over Nostr, the decentralized protocol the documentation names for this purpose. One instance can share index data with peers without relying on a central server. Operators choose which peers to connect to, so review that setting carefully.
No. CMN Synapse is an indexer for the CMN network, so it does not store coins, keys or seed phrases and does not mine. Its job is ingesting signed manifests, indexing content and answering discovery queries, and it should be kept updated like any network service.
Verdict
CMN Synapse is a strong choice for developers and community operators who want to run a discovery node for the CMN network. It is free, open source, written in Rust, and actively updated. It is not a desktop app for everyday users, and Windows support should be confirmed on the Releases page before you commit. If you mainly want to browse Nostr, pick a client instead. If you want to help keep CMN content discoverable and resilient, Synapse is worth running once you have verified the download.