Hey Cardanians! Welcome aboard the Weekly Cardano Digest #145!

We've filtered through all the noise to distill crucial updates into a breezy, 5-minute read. No need for you to sift through endless info ,we've got you covered. Ready to delve into this week's top Cardano news? Let’s dive in.

Here are the topics of the week:

• 🚀 RealFi Goes Live on Cardano Mainnet

• ⛽ Petrobras Puts Renewable Fuel Proofs on Cardano

• 🌙 Permissionless Smart Contracts Go Live on Midnight Mainnet

• Weekly Development Report

• & More!

🚀 RealFi Goes Live on Cardano Mainnet

 RealFi went live on Cardano mainnet, hitting the date it set back in September. The launch opens what the team calls Voyager Season at app.realfi.co, and it arrives with more than 3,000 verified wallets and tens of thousands of test actions behind it from the public testnet phase.

What makes this launch different from most mainnet days is that the surrounding infrastructure was already built. RealFi shipped with integrations live in Lace, Liqwid and SundaeSwap on day one, so users reach it from wallets and DEXs they already run rather than a standalone app nobody has bookmarked. Lace 2.4 landed the same week with RealFi features built directly into the wallet, including a swap review screen that spells out what leaves your wallet, the fee, where the order goes and what is held as collateral.

Sundae V4, which also went live October 1, built a pool type for it: Linear Swaps, where the USDrf/USDCx pair holds a fixed 1:1 price with zero slippage at any size as long as the pool has depth. The USDrf/sUSDrf pair runs on a Stableswap pool whose peg rises on-chain as sUSDrf earns yield. An expansion to EVM networks is planned next. For #Cardano it means the real-world-asset stablecoin layer landed with its plumbing already connected.

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⛽ Petrobras Puts Renewable Fuel Proofs on Cardano

Cardano Foundation announced that Petrobras — Brazil's state-controlled energy giant — is piloting two blockchain traceability applications on Cardano, with researchers from PUC-Rio on the project.

The first covers sustainable aviation fuel (SAF) using a book-and-claim model, where the environmental attributes of the fuel travel separately from the physical barrels. That separation is what makes the accounting work: an airline buying SAF credits for a route it flies out of Frankfurt does not need the molecules to have been in that specific plane, but it does need certainty that nobody else claimed the same reduction. The system can issue digital certificates down to an individual passenger's itinerary. The second application tracks Diesel R, Petrobras' renewable diesel, across production, transport and use, building a continuous lifecycle record that supports Scope 3 emissions reporting back through suppliers and logistics providers.

Both remain research-and-development projects rather than commercial rollouts, which is worth stating plainly. But the reason a public chain is the right venue is structural: the data has to be trusted by parties who do not trust each other and who are not on each other's systems. "The energy transition will depend as much on trust as it does on new fuels," said Rafael Fraga, the Foundation's LATAM business development lead. #Cardano is being used here as neutral ground, not as a database.

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🌙 Permissionless Smart Contracts Go Live on Midnight Mainnet

Midnight opened its mainnet to permissionless smart contract deployment. Developers no longer need a mandatory security review on Preprod before shipping to production, and contracts can now programmatically deploy other contracts — the pattern that factories, account abstraction and most composable DeFi depend on. Teams can also deploy on behalf of end users, which removes one of the sharpest edges in onboarding.

This closes out the controlled launch phase Midnight has run since March 2026. The network launched with a gate on who could deploy, which is a reasonable way to start a privacy chain and an impossible way to grow one: every new application had to wait on someone else's calendar. Removing the gate is the difference between a network that ships what its team approves and one that ships whatever its builders write. Midnight still recommends testing on Preprod first, which is advice rather than a checkpoint.

The same State of the Network report lists OpenZeppelin — now owned by S&P Global — continuing to build libraries for Midnight, Ura Labs piloting fee sponsorship through Relay Club, and Google Cloud supplying dedicated testnet infrastructure and NIGHT faucets. A Korea hackathon closed with a $6,000 prize pool, and a VIA Labs sprint put 37 developers to work producing five payment applications on USDM.

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Essential Cardano’s weekly development report