Keydex is a free, open source Nostr key management application for Windows, built for people who want more control over the keys behind their Nostr identity. If you publish notes or follow accounts on Nostr, your identity depends on a pair of cryptographic keys, and how you store and handle them matters a great deal.
This page covers what Keydex does, how to install it from the official sources, how to use it with care, and how it compares with other Nostr tools in this catalog. The project is released under the MIT license, its source code is public on GitHub, and the latest release is v1.0.1-37. Because Nostr keys are simple strings that grant full control, small habits make a big difference. Read the safety section before you import or paste any private key into Keydex for Windows.
What Is Keydex and Who Is It For?
Keydex is a key management tool, so its natural audience is people who already use Nostr and want a dedicated place to handle the keys behind their identity. Think of someone who posts from several clients and wants to keep the underlying key material organized rather than scattered across notes and files.
Developers and technically curious users also benefit. Because the project is open source, people who build Nostr applications can study how key handling is implemented, test ideas and contribute fixes. Developers who want to build Keydex from source should follow the project's own instructions on GitHub.
If you are new to Nostr, start by learning the basic model before using any key manager. Understanding the difference between a public identifier and a private signing key will help you make better decisions about what to store and where.
How Nostr Keys Work: npub and nsec Explained
A Nostr identity is a key pair. The public key, usually shown in bech32 form beginning with npub, is what other people and apps use to find and follow you. The private key, usually shown as nsec, is used to sign your events so that others can verify they really came from you.
The practical consequence is simple: whoever holds your nsec can act as you. Nostr has no central company that can reset a password or freeze an account for you, so the private key is the single most important secret in the system. Losing it can mean losing control of the identity, and exposing it can mean someone else gains control.
A key manager exists to reduce those risks. It gives you one place to see which keys you hold, which ones you have backed up and which ones you can retire. Keydex is built around that job, so understanding the npub and nsec distinction is the first step to using it well.
Why Open Source Matters for a Key Manager
Software that handles private keys asks for trust. An open source license changes the conversation, because the code can be inspected by anyone who wants to check how keys are stored, displayed and transmitted. For Keydex, the MIT license and the public GitHub repository mean that claims about the app can be checked rather than accepted on faith.
Open source also helps the community catch problems. Researchers and users can open issues, suggest fixes and compare behavior across versions. A small project with an engaged codebase is easier to scrutinize than a closed program, although that does not replace your own care.
Finally, the license gives you freedom. You can fork the project, adapt it for a specific workflow or keep a copy of a version you trust. Those options are rarely available with closed key tools, and they are a real reason to choose open software in this category.
Key features
Free and open source
Windows build or installer
Built with Dart and Flutter
Focused on Nostr keys
Supported coins
The project documentation mentions Bitcoin (BTC) and Nostr, so those are the networks to review first. Keydex is centered on Nostr identity, and Bitcoin appears in the documentation as a related network. Check the documentation for the current details before relying on the app for any Bitcoin-related keys.
How to install Keydex on Windows
- 1
Get the Windows file from GitHub
Open the Releases page for the project at github.com/mplorentz/keydex and download the Windows build or installer for the latest version, v1.0.1-37. Use only the official download source for the project, and do not accept copies from forums, file mirrors or messages.
- 2
Verify the download
Compare the SHA-256 checksum of the file you downloaded with the value published on the release page. If no checksum is listed, look for a signature where the release provides one. Do not run any file whose hash does not match the published value.
- 3
Run the installer
Double-click the installer and follow the on-screen prompts. If the release you downloaded is a portable build rather than an installer, extract it to a folder you control and launch the executable from there. Keep the file in a location you can find again when updating.
-
Complete the first launch
Open Keydex, read the on-screen prompts and confirm the app is working before you add any sensitive key. Make sure your Windows account and session are secured, since anyone with access to your unlocked computer may be able to view what the app displays.
How to use Keydex
Keydex is simple to start with, but treat every key you load as sensitive. Work through the steps below in a calm moment, and avoid using a shared or public computer.
- Install Keydex from the official source and verify the file as described in the installation section.
- Launch the app and read the main screen before adding any key, so you know where your keys are displayed.
- Start with a test key if you have one, so you can learn the workflow without risking your main identity.
- Record your private key in a password manager or an offline notebook before making any changes.
- Close Keydex when you are not using it, and lock your Windows session when you step away from the computer.
- Review your stored keys from time to time and remove any you no longer need.
Take your time with each step. If something looks unfamiliar, stop and check the project documentation before continuing.
Pros & cons
- Free to use
- Open source under the MIT license
- Source code publicly available on GitHub
- Windows build or installer available
- Recent code update, so the project is active
- Narrow scope: it manages keys rather than acting as a full Nostr client
- The 1.0.x release line is early, so expect changes between versions
- A key manager is only as safe as the habits around it, and mistakes with private keys are hard to undo
Is Keydex safe?
Keydex handles private keys, which grant full control over a Nostr identity, so safety matters more here than with a typical desktop utility. Download the program only from the official GitHub Releases page for the project, and verify the SHA-256 checksum or signature before running the file. Never enter an nsec or a seed phrase on a third-party website, and be wary of any site or message that asks for your key in exchange for a service.
Antivirus tools may flag new or unsigned software. If that happens, investigate the warning and check the file hash rather than turning protection off. Keep a secure offline backup of your private keys. Before updating, check the latest version on the official website.
- Official source only. Download from github.com/mplorentz/keydex. 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
Keydex sits in a different place from most entries in this Nostr category. Vega and Notedeck are desktop clients for browsing and posting on Nostr, while Keydex focuses on the keys that sign your activity. Nostrid offers a client across several platforms, so it is the closer match for people who want a single app to read and post.
Bold Bitcoin Wallet uses MPC over Nostr for device pairing and transaction signing, which is a different design from a dedicated key manager. If you need a client, start with Vega or Nostrid. If your priority is managing the keys behind any of them, Keydex is the more relevant choice.
Specifications
- Price
- Free
- Type
- Open source
- License
- MIT
- Latest version
- v1.0.1-37
- Last update
- 26 Aug 2026
- Windows support
- Yes (Windows build or installer)
- Source code
- github.com/mplorentz/keydex
Frequently asked questions
Yes. Keydex is free, and its source code is released under the MIT license, which allows you to use, study, modify and redistribute it. Free software still requires careful handling of your keys, so read the safety section before you start.
It can be, if you get it from the official GitHub Releases page, verify the checksum and keep your private keys backed up offline. Because Keydex handles keys, a compromised download or a phishing site could expose your identity. Check each file, avoid entering keys on third-party websites and keep Windows updated.
Go to the project's Releases page on GitHub at github.com/mplorentz/keydex and choose the Windows build or installer for the latest version, v1.0.1-37. Verify the file's SHA-256 checksum before running it. The installation section walks through each step in order.
Yes. Keydex is open source under the MIT license, and its code is hosted on GitHub at github.com/mplorentz/keydex. You can read how the app works, report issues or build it yourself. Most users simply install the ready-made Windows program and never need the source code.
The project documentation mentions Bitcoin (BTC) and Nostr. Keydex is primarily a Nostr key management application, so Nostr is its core focus. Before relying on it for Bitcoin-related keys, read the documentation and test with a non-essential key first.
A Nostr identity is a key pair. The public key, usually shown as an npub, is what others use to find and follow you. The private key, usually shown as an nsec, proves you control the identity and signs your posts. Anyone who holds the nsec can act as you, so it should stay private.
No. Dart and Flutter are build-time tools that developers use to compile the app. If you install the ready-made Windows build or installer, you do not need to install them. You only need them if you plan to build Keydex from its source code on GitHub.
Verdict
Keydex is a good fit for Windows users who already use Nostr and want a dedicated, open source tool for managing their keys. It is free, MIT licensed and actively maintained. It is not a full social client, so pair it with a client such as Vega or Nostrid if you also want to read and post. Treat your private key like the password to your entire identity, keep a secure offline backup and verify every download before you run it.