TL;DR Test APIs behind a firewall or on development machines using
1. Download ngrok
The first step is to download a program to expose
another url behind a firewall to the Internet. We'll use ngrok which is a
program can be downloaded for free and
available for all major operating systems.
Download and unpack ngrok.
$ unzip /path/to/ngrok.zip
2. Start ngrok
The next step is to expose your web service. If your web service is on
localhost, simply run the following on the command-line:
$ ngrok http 3000
If you need to point
ngrok to another host behind a firewall
(e.g. inside an intranet), use the full host instead of a port only:
$ ngrok http internal.host:8099
You should see a line that looks something like this:
Forwarding http://7e9ea9dc.ngrok.io -> 127.0.0.1:3000
Forwarding http://7e9ea9dc.ngrok.io -> internal.host:8099
*.ngrok.io URL to your clipboard or write it down.
Testing a host that is not
If the web service you are trying to test is using another host that's
localhost, for example
can make a tunnel by customizing the
ngrok command using the
-host-header command-line flag:
./ngrok http -host-header=rewrite private.behind-firewall.com:80
3. Create a web service in Assertible
Next, create a web service in the Assertible dashboard.
Use the ngrok URL obtained in step 2 as the host of your Assertible
web service (e.g.
4. Start testing!
Assertible will automatically run a test once when you create a new API to help you get oriented with the results.
You should see a similar output in
ngrok (although you may not have
From this point, you are completely setup and free to configure Assertible to test various aspects of your API or web app. Have fun!
Resources and documentation
:: Christopher Reichert
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