macOS: How to install a local SSL certificate in macOS

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You’ve written an app that should use HTTPS, but it’s not working: you’re getting a warning when you try to access it using HTTPS, even though you created a local certificate.

That’s because by default the browser does not trust local certificates.

We need to install it!

I assume you use Chrome in this section

Click the “Not Secure” box near the address bar, and a little panel should show up:

Click the Certificate item in the box, and you should see another panel show up, with the certificate details:

Now drag the certificate icon from there to the desktop, or any other folder you want. Literally drag and drop using the mouse.

Once you do so, find the file in the Finder, and double-click it.

You should see a prompt to install it:

Where you see the Keychain: option, instead of login, choose System:

Press Add, now you should see the certificate in the System keychain, listed as localhost:

Now double-click that, and this window should show up:

Click the arrow near Trust, and you should see this window, make sure you change “When using this certificate” to “Always Trust”.

That’s it! Now close the Keychain app (cmd-Q) and try reloading your Chrome tab, it should work!

And it should now work across any browser you use.

Lessons in this unit:

0: Introduction
1: How to use the macOS terminal
2: Productivity gains of using a Mac and an iOS device
3: A way to set up automations in macOS easily
4: How to hide a file or folder in macOS Finder
5: ▶︎ How to install a local SSL certificate in macOS
6: Reverting a file to a previous version, on a Mac
7: Take screenshots as JPG on macOS
8: Convert an image or resize it using macOS Shortcuts
9: Concatenating videos on macOS
10: Fix files creation date in macOS
11: Freeing space on a Mac
12: How to add an “Open in Terminal” icon in macOS Finder
13: How to add an “Open in VS Code” icon in macOS Finder
14: How to find the bundle ID of a Mac app
15: How to Fix the "Your CLT does not support macOS 11" error in macOS
16: How to play a sound from the macOS command line
17: How to remove the shadow from window screenshots in macOS
18: Removing all Homebrew stuff
19: Run a Node.js script from your macOS menu bar