Tidal Observation Card

Each player receives twelve Tidal Observation Cards per day, and the set refreshes on a daily cycle. A card's reward stays hidden until the player pays the observation cost to flip it. Once the content is shown, the player decides whether to pay the redemption cost to take the reward or to give it up and keep nothing from that card. The two steps are separate, so a revealed reward can still be a poor trade once its redemption price is counted.

The mod is built around that two-step decision rather than a plain daily lottery. Observation cost and redemption cost are configured independently, which lets a modpack designer choose different resource sinks for each step. Two kinds of voucher exist, split into five tiers each; a valid voucher is consumed before the original currency item when a cost is paid. Costs, currencies, reward pools, compensation and tier values can all be changed in the config file.

The card system is a NeoForge mod built for 1.21.1 – 1.21.11 and is released under All rights reserved, so the code is not open source. A server running it needs every connecting player to have it too. Public links exist for the source code, issue tracker and wiki.