mkcert is a simple tool for making locally-trusted development certificates. It requires no configuration.
$ mkcert -install Created a new local CA 💥 The local CA is now installed in the system trust store! ⚡️ The local CA is now installed in the Firefox trust store (requires browser restart)! 🦊 $ mkcert example.com "*.example.com" example.test localhost 127.0.0.1 ::1 Created a new certificate valid for the following names 📜 - "example.com" - "*.example.com" - "example.test" - "localhost" - "127.0.0.1" - "::1" The certificate is at "./example.com+5.pem" and the key at "./example.com+5-key.pem" ✅
Using certificates from real certificate authorities (CAs) for development can be dangerous or impossible (for hosts like
127.0.0.1), but self-signed certificates cause trust errors. Managing your own CA is the best solution, but usually involves arcane commands, specialized knowledge and manual steps.
mkcert automatically creates and installs a local CA in the system root store, and generates locally-trusted certificates. mkcert does not automatically configure servers to use the certificates, though, that's up to you.
rootCA-key.pemfile that mkcert automatically generates gives complete power to intercept secure requests from your machine. Do not share it.
On macOS, use Homebrew
brew install mkcert brew install nss # if you use Firefox
sudo port selfupdate sudo port install mkcert sudo port install nss # if you use Firefox
On Linux, first install
sudo apt install libnss3-tools -or- sudo yum install nss-tools -or- sudo pacman -S nss -or- sudo zypper install mozilla-nss-tools
Then you can install using Homebrew on Linux
brew install mkcert
or build from source (requires Go 1.13+)
git clone https://github.com/FiloSottile/mkcert && cd mkcert go build -ldflags "-X main.Version=$(git describe --tags)"
or use the pre-built binaries.
For Arch Linux users,
mkcert is available on the official Arch Linux repository.
sudo pacman -Syu mkcert
On Windows, use Chocolatey
choco install mkcert
or use Scoop
scoop bucket add extras scoop install mkcert
or build from source (requires Go 1.10+), or use the pre-built binaries.
If you're running into permission problems try running
mkcert as an Administrator.
Supported root stores
mkcert supports the following root stores:
- macOS system store
- Windows system store
- Linux variants that provide either
update-ca-trust(Fedora, RHEL, CentOS) or
update-ca-certificates(Ubuntu, Debian, OpenSUSE, SLES) or
- Firefox (macOS and Linux only)
- Chrome and Chromium
- Java (when
To only install the local root CA into a subset of them, you can set the
TRUST_STORES environment variable to a comma-separated list. Options are: "system", "java" and "nss" (includes Firefox).
-cert-file FILE, -key-file FILE, -p12-file FILE Customize the output paths. -client Generate a certificate for client authentication. -ecdsa Generate a certificate with an ECDSA key. -pkcs12 Generate a ".p12" PKCS #12 file, also know as a ".pfx" file, containing certificate and key for legacy applications. -csr CSR Generate a certificate based on the supplied CSR. Conflicts with all other flags and arguments except -install and -cert-file.
Note: You must place these options before the domain names list.
mkcert -key-file key.pem -cert-file cert.pem example.com *.example.com
mkcert automatically generates an S/MIME certificate if one of the supplied names is an email address.
For the certificates to be trusted on mobile devices, you will have to install the root CA. It's the
rootCA.pem file in the folder printed by
On iOS, you can either use AirDrop, email the CA to yourself, or serve it from an HTTP server. After opening it, you need to install the profile in Settings > Profile Downloaded and then enable full trust in it.
For Android, you will have to install the CA and then enable user roots in the development build of your app. See this StackOverflow answer.
Using the root with Node.js
Node does not use the system root store, so it won't accept mkcert certificates automatically. Instead, you will have to set the
NODE_EXTRA_CA_CERTS environment variable.
export NODE_EXTRA_CA_CERTS="$(mkcert -CAROOT)/rootCA.pem"
Changing the location of the CA files
The CA certificate and its key are stored in an application data folder in the user home. You usually don't have to worry about it, as installation is automated, but the location is printed by
If you want to manage separate CAs, you can use the environment variable
$CAROOT to set the folder where mkcert will place and look for the local CA files.
Installing the CA on other systems
Installing in the trust store does not require the CA key, so you can export the CA certificate and use mkcert to install it in other machines.
- Look for the
- copy it to a different machine
$CAROOTto its directory
Remember that mkcert is meant for development purposes, not production, so it should not be used on end users' machines, and that you should not export or share