6 posts tagged with "utxorpc"

This is part two of a two-part series on building a presale on Cardano. Part one covered the on-chain contract - how a purchase receipt is enforced so a participation is only recorded if the buyer really paid. This post is about the app on top of it.

Standing up a presale used to mean wiring a sale contract, an indexer, a payment flow, and a UI before you could take a single order. With the EffectStream preorder launchpad, creating a campaign on Cardano comes down to two steps: clone and publish. This post walks through the app built on top of that contract - and the piece that makes the Cardano side genuinely fast: UTxORPC.

A presale (a launchpad / preorder) sells a catalog of items before they exist: a buyer commits funds now, and the project records who bought what so it can fulfil later. The thing you actually want to guarantee is simple to say and surprisingly subtle to enforce: a participation should only be recorded if the buyer really paid for it — the right amount, to the right address, while the sale is open, and (optionally) crediting whoever referred them.

This post is about doing that guarantee on-chain on Cardano, with a small Aiken minting-policy validator that issues a "purchase receipt" only when the payment rules are met — and about where the rest of the presale logic (catalog, prices, conversion rates) lives so the whole thing stays deterministic. The same app also runs the EVM flow, and the Cardano contract is built to be compatible with that EVM presale — same catalog, same referral model, same recorded state — which we'll come back to once the Cardano picture is clear.

When we set out to connect Cardano to game state, we started from the obvious place: write an indexer task. Each new use-case got its own custom Carp module, its own SQL schema, its own glue code. After the third one - stake-pool delegation, projected NFTs, native-asset transfers - it was clear we'd been writing the same scaffold three times. EffectStream now ships those scaffolds as Cardano Primitives: a shared architecture that turns Dolos/UTxORPC streams into typed, queryable state machine events, with five concrete primitives delivered out of the box.

Users want to use their NFTs in applications (games, DeFi, social platforms) without giving up ownership. Projected NFTs solve this: lock an NFT on Cardano L1 and use a representation in your application. The NFT never leaves your wallet in any meaningful sense; it's locked in a smart contract you control, and you can unlock it at any time.

A step-by-step walkthrough of how the EffectStream cardano-delegation template works internally. We'll trace the full path from raw Cardano blocks to application state, covering the config, primitive, grammar, state machine, database, and API layers.

Cardano's stake pool ecosystem has millions of ADA delegated across hundreds of pools, but delegation has always been a one-way relationship: delegators earn rewards, and that's it. What if games and apps could react to where you delegate? What if stake pool operators could offer in-game benefits to their delegators? EffectStream now makes this possible with a new PoolDelegation primitive that streams delegation changes in real-time.