There are 2 repositories under payoff-graphs topic.
A software to shortlist and find the best options spread available for a given stock and help it visualise using payoff graphs.
An option payoff visualizer that allows you to add and customize strategies and visualize their payoffs. Site built with React, Material UI and D3.
Free WordPress Plugin: Free online credit card calculator that provides valuable information to users, including how to minimize debt and a credit payment calculator with recommended payment amounts. www.calculator.io/credit-card-payoff-calculator/