Alacritty

sudo pacman -S alacritty

This is my config file located in $HOME/.config/alacritty/alacritty.yml.

window:
  opacity: 0.94
  startup_mode: Maximized
font:
  size: 10.5
shell:
  program: /bin/zsh
  args:
    - -l
    - -c
    - tmux new-session -A -s dev

You can find  config file from github, or click download here and download the latest version of the alacritty.yml.

• -l, stands for login shell. This tells Alacritty to start the shell that is specified in the $SHELL environment variable.
• -c, stands for command. This tells Alacritty to run the specified command after the shell has been started.