Insomnia — это программа для тестирования REST API.

https://insomnia.rest/

Установка Insomnia на Ubuntu/Debian:

# Add to sources
echo "deb https://dl.bintray.com/getinsomnia/Insomnia /" \
    | sudo tee -a /etc/apt/sources.list.d/insomnia.list

# Add public key used to verify code signature
wget --quiet -O - https://insomnia.rest/keys/debian-public.key.asc \
    | sudo apt-key add -

# Refresh repository sources and install Insomnia
sudo apt-get update
sudo apt-get install insomnia

Другие ОС: https://support.insomnia.rest/article/23-installation