Adam Cazes Demonstrates How Nexus Powers GeroWallet and Tracks Cardano Activity

Adam Cazes, co-founder and CEO of A.D. Labs, demonstrated the infrastructure behind GeroWallet during Cardano Developers Office Hours. His presentation focused on Nexus, the data and transaction platform originally built for the wallet and now available to other developers.

Cazes showed how Nexus delivers portfolio information, finds swap routes and monitors selected blockchain activity. He also discussed its use of Yaci Store, the team’s work on AI agent infrastructure and the challenges of supporting applications across multiple chains.

How Nexus Supports GeroWallet and Other Applications

A crypto wallet brings together information from several sources before a user sees a balance, transaction history or swap quote. It needs to retrieve records from the blockchain, identify the assets associated with an account and connect them with market information.

Cazes explained that GeroWallet previously relied on repeated requests to backend services for this information. As the number of users grew, the team faced increasing network and maintenance costs. A.D. Labs developed Nexus to organize data in its backend and deliver it to the wallet.

To illustrate the workload, he displayed a wallet with approximately 840 transactions. Each record can contain multiple pieces of information, including metadata, scripts, collateral and unspent transaction outputs, or UTXOs. On Cardano, UTXOs represent available outputs that can be used to construct new transactions.

Nexus supports data access for Cardano, Midnight and Bitcoin. Cazes explained that Midnight needs its own index because its architecture includes features such as proofs and DUST generation. Indexing organizes blockchain information so applications can retrieve the records they need.

The platform also combines market data with a decentralized exchange aggregator. In a demonstration application, Cazes entered an ADA swap amount and displayed a proposed route, other available trading venues and the estimated price impact.

He identified SongMarketCap as a Nexus partner that uses the platform’s market data and decentralized exchange aggregator. Other potential users he listed included wallets, developers building applications and AI agents.

A separate transaction-building demonstration produced an unsigned transaction in CBOR format, a way of encoding data. The transaction must then be signed by the user’s wallet or application before submission.

Blueprints Stream Cardano Transactions Through WebSockets

Cazes also demonstrated how developers can follow specific blockchain activity without repeatedly asking whether anything has changed.

One common method, known as polling, sends requests at regular intervals. If no relevant transaction has appeared, the request returns without a new result. Applications that check frequently can therefore generate large numbers of requests even during quiet periods.

Nexus offers a second approach through WebSockets, connections that allow applications to subscribe to events and receive updates as they arrive. Its Blueprints feature lets developers define the activity they want to follow.

During the session, Cazes created a subscription for transactions associated with a token policy on Cardano mainnet. He explained that developers can also filter activity using an address, staking credential or script hash, depending on the application. Results can be delivered at the transaction level or for individual UTXOs.

Cazes presented FluidTokens, a Nexus design partner, as an example of how the system can be used for a lending application. His case study covered one script associated with 115 addresses and showed that only a small portion of the blocks examined contained activity relevant to the application.

In a separate polling demonstration involving the NIGHT token, Cazes reported that approximately 80% of requests returned without new information. The number of requests an application can avoid depends on its polling frequency and the level of activity it monitors.

Developers also asked how a streaming system handles a rollback, an event in which previously observed chain history is replaced. Participants explained that rollback events can be delivered to subscribers, while the receiving application is responsible for updating its own records accordingly.

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Yaci Store, AI Agents and Expansion Plans

Nexus primarily uses Yaci Store to index Cardano data. Cazes explained that A.D. Labs runs a modified version based on Yaci Store 3.0 Beta 5 and has submitted its changes to the upstream project.

The system can also use other data providers as fallbacks. Cazes identified Koios as one source Nexus can consult when information is unavailable from its primary infrastructure.

During a comparison presented in the session, Cazes reported that Nexus had a median lead of approximately two seconds over Blockfrost in delivering newly observed blocks in his test. He linked the result partly to the Nexus architecture and its use of Yaci Store.

Beyond blockchain data, Nexus includes an MCP server, which provides a way for AI agents to connect with supported tools and information. One participant suggested adding an x402 facilitator, a component described during the session as handling transaction submission and status tracking for agents.

Cazes responded that A.D. Labs had already begun building infrastructure for an agent mode in GeroWallet. The x402 facilitator was discussed as a possible future service, with no launch announced during the presentation.

The team is also considering support for additional networks, including EVM chains and Solana. Cazes connected that work with GeroWallet’s roadmap and the goal of making interactions across blockchains easier for users.

At the time of the session, Nexus offered a seven-day trial and an introductory plan priced at $9 per month. Asked about a free tier, Cazes confirmed that the team had considered one but had not introduced it under its existing business model.

Disclosure: SongMarketCap uses a swap widget powered by Gero Nexus and receives a share of the swap fees generated through the widget.