Powering Decentralized Applications: UDF’s Pull Model Explained

Editor’s Note (March 2025): This article covers the Pull Model before the UDF Marketplace launch. For the most up-to-date architecture and developer guides, see our latest article called: UDF Marketplace: Revolutionizing Push and Pull Oracle Services.

1. Introduction

Every transaction, every decision is built on speed and trust. Real-time, verifiable data fuels dApps, keeping lending protocols sharp with instant asset pricing and gaming platforms synced with live events. Whether it’s a lending protocol requiring up-to-date asset prices or a gaming platform needing consistent event information, timely and trusted data underpins the entire user experience.

Universal Data Feeds (UDF) addresses this challenge by providing a next-generation oracle system that leverages Layer 2 (L2) scaling of the Entangle Interoperable Blockchain (EIB), and robust cryptographic proofs. By combining on-chain verification with decentralized publishing, UDF delivers near-instant (200ms frequency) data updates across EVM and non-EVM networks, empowering dApps to pull the latest verified data on demand.

Note: This article covers UDF’s Pull Model as currently implemented. A new version powered by dedicated marketplace contracts, offering subscription options and Pay-As-You-Go (PAYG), is launching shortly. We’ll cover it in our upcoming article on the UDF Marketplace.

2. Pull Model Features

Real-Time On-Demand Verification

UDF’s Pull Model enables data verification during the transaction execution. In practice, the process typically looks like this:

1. Fetch Off-Chain Update Data:
   • You can retrieve the latest oracle update from a Finalized Data API, such as https://udfsnap.ent-dx.com/last_votes?feedKeys=BTC/USD, to get the most recent oracle votes, signatures, and feed details.
   • Alternatively, you can install the @entangle-labs/udf-sdk library (via yarn add --dev @entangle-labs/udf-sdk) and use its built-in methods like sdk.getCallData(["BTC/USD"]) which returns an encoded payload containing the latest signed oracle update ready to pass on-chain.
2. Embed Verification Data in Your Transaction:
   • Pass the off-chain data (e.g., updateData) as a bytes calldata parameter to your consumer smart contract.
   • With the upcoming UDF Marketplace release, developers should integrate directly with the new PullMarketplace contract using:
     • verifyWithFee(updateData, feedKey) for Pay-As-You-Go (PAYG) usage
     • verifyAsSubscriber(updateData, feedKey) for subscription-based access

These methods provide real-time, in-transaction oracle verification using cryptographically signed updates.

For complete examples and code snippets, refer to the latest UDF Developer Guides.

3. Real-Time Contract Verification:
   • The contract parses and verifies these signatures in real time, ensuring only valid data is used for your transaction.
   • If the data is invalid or outdated, the transaction reverts, preserving security.

By embedding the latest oracle updates directly into each transaction, the feed is as fresh as the aggregator’s most recent consensus. This drastically reduces data staleness, critical for time-sensitive operations like derivatives trading or automated liquidations.

Low-Cost Updates with Customizable Access

Because the Pull Model defers on-chain updates to when they’re needed, dApps can be highly selective:

• Fine-grained control: Only retrieve data for the specific assets or parameters relevant to each transaction.
• Single-transaction verification: Everything occurs in one atomic call, preventing partial or outdated updates from slipping through.

Developers can refer to the UDF Pull Model Developer Guide for:

• Hardhat setup (initializing a project, installing dependencies)
• Sample PullConsumer contract implementation (note: the example will soon be replaced in the new marketplace)
• Deployment and usage instructions (scripts to fund the contract and submit real-time data)

3. Decentralized Infrastructure

EIB: A Specialized Oracle Chain

UDF runs on the Entangle Interoperable Blockchain (EIB), a specialized oracle chain that orchestrates and secures data for cross-chain consumption. The EIB provides:

• High-speed aggregation: Multiple transmitters collect off-chain data points, sign them, and finalize a consensus.
• Robust security: EIB’s Byzantine Fault Tolerant (BFT) consensus ensures no single transmitter can compromise the feed.
• Cross-chain bridging: Finalized snapshots are bridged to target chains, enabling a truly omnichain approach.
• L2 Scalability: As highlighted in our previous article Introducing UDFv1.1, the EIB leverages Layer 2 rollups to parallelize aggregator operations, drastically reducing latency (200ms update frequency), and increasing throughput.

By offloading data aggregation onto a dedicated chain, UDF unburdens dApps from needing to handle large or frequent on-chain updates themselves. This architecture delivers real-time data without congesting the underlying L1 network.

Omnichain Functionality

Beyond EVM-based ecosystems, UDF’s design extends to other networks. UDF facilitates data for multiple blockchains. Whether it’s an EVM chain, Cosmos, Solana, Ton, or another chain, UDF ensures a universal feed for reliable data. To see which networks and assets are currently supported, visit our Data Endpoints page.

4. Developer Benefits

Flexibility

The Pull Model grants full control over when and which data is verified. If your app needs data once a week, you only include the feed in that weekly transaction. If it needs updates on every user interaction, you can fetch them every transaction. This also supports custom data feeds, letting you register specialized data sources for real-world assets, gaming stats, or any other domain-specific metrics. The upcoming PullMarketplace will retain this flexibility while simplifying integration and offering billing mechanisms (subscriptions or per-use fees) directly via the marketplace UI.

Scalability

As your dApp or user base grows, UDF’s decentralized aggregator network scales to meet demand, without forcing you to manage more frequent or heavier on-chain pushes. The overhead remains proportional to your actual usage, and the EIB’s L2 solutions provide ample room for horizontal expansion.

Cost-Efficiency

Since verification happens on-demand within the user transaction, there is no recurring overhead for data you don’t actually consume. The new PullMarketplace will maintain this on-demand architecture while introducing transparent fee structures via the UI and smart contracts. You simply pay for the transaction fees on your target chain for the verification process.

Extensibility via Custom Data Feeds

One of UDF’s most powerful advantages is how easily you can add new data feeds. Whether it’s real-world assets (RWAs), synthetic assets, or specialized gaming stats, you can engage the UDF team or follow our Custom Data Feeds guide to request or define your own feed type. This ensures your dApp remains agile in an ever-evolving Web3 landscape.

5. Future Vision

UDF’s roadmap includes expanding cross-chain integrations, enhancing aggregator throughput, and expanding the new UDF Marketplace, our soon-to-launch interface and protocol upgrade that brings Push and Pull services under one roof. With monetization tools, usage dashboards, and simplified access via PullMarketplace and PushMarketplace contracts, it’s built to power scalable oracle consumption across ecosystems and we're excited for developers to start building with it. The core focus remains technical excellence, delivering real-time, trust-minimized data feeds that power the next generation of dApps.

Additionally, we’re proud to see our data feeds being adopted by partners like quaimark and shadowforge.ai, who leverage UDF respectively for DeFi and AI decentralized applications.

6. Get Started with the UDF Pull Model

For an in-depth walkthrough, from initializing a Hardhat project to deploying your PullConsumer contract, head over to the official UDF Pull Model Developer Guide. There you’ll find:

• Code examples for verifying updated prices or data
• Guidance on bridging data across various networks
• Troubleshooting tips for common integration pitfalls

Looking for unique data feeds or want to propose something new? Explore our Custom Data Feeds documentation. We’re always open to collaboration, if you need something special, we’ll help you integrate it.

To prepare for the UDF Marketplace launch, explore the latest documentation and bookmark the Marketplace UI, going live soon with fully integrated Push and Pull data access.