Test API endpoint with netcat

Do you need a simple way to validate that an API endpoint is responsive, but you don't want to use curl?
There is a simple way to validate the endpoint with nc, producing an output that can be redirected to a logfile and parsed later:

URL=$1
PORT=$2

while true; do
    RESULT=$(nc -vz $URL $PORT 2>&1)
    DATE=$(date)
    echo $DATE $RESULT

    sleep 1
done

You can all this script with the API URL as first parameter, and API port as the second.
netcat will be accessing to that endpoint and will report the results, detecting when the API is down. We also can output the date to have a reference when failures are detected.

The produced output will be something like:

vie jun 26 08:19:28 UTC 2020 Ncat: Version 7.70 ( https://nmap.org/ncat ) Ncat: Connected to 192.168.111.3:6443. Ncat: 0 bytes sent, 0 bytes received in 0.01 seconds.
vie jun 26 08:19:29 UTC 2020 Ncat: Version 7.70 ( https://nmap.org/ncat ) Ncat: Connected to 192.168.111.3:6443. Ncat: 0 bytes sent, 0 bytes received in 0.01 seconds.
vie jun 26 08:19:30 UTC 2020 Ncat: Version 7.70 ( https://nmap.org/ncat ) Ncat: Connected to 192.168.111.3:6443. Ncat: 0 bytes sent, 0 bytes received in 0.01 seconds.
vie jun 26 08:19:44 UTC 2020 Ncat: Version 7.70 ( https://nmap.org/ncat ) Ncat: Connection refused.

You can simply watch it on your terminal, or redirect the output to a file or to some log processing system for later consumption.