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Randcast Playground Upgrade: Multi-Chain, Low-Latency Randomness with Verifiable Draw, Roll, and Gacha Modes

Verifiable randomness is a core primitive for many Web3 applications, from community lotteries and giveaways to games, NFT drops, and probabilistic mechanics. Over the past months, we’ve been iterating on Randcast Playground to make decentralized randomness easier to try, easier to understand, and easier to build with.

Randcast is an on-chain verifiable randomness service that leverages the ARPA Network to generate decentralized, verifiable randomness. Randomness requests are handled by multiple ARPA Network nodes performing BLS threshold signature tasks. The resulting signature is verified on-chain by the Randcast Adapter contract and then used as input for randomness generation.

The Randcast Playground provides a public interface for interacting with deployed Randcast consumer contracts, allowing users to submit randomness requests and observe on-chain results without deploying contracts themselves.

Recent Updates to the Randcast Playground

The Randcast Playground has recently been upgraded to support a broader range of networks and use cases. A new version of the Playground frontend is now live at https://www.arpanetwork.io/play, making it easier to interact with Randcast across different environments. The Randcast product page has also been updated to make the Playground entry easier to discover at https://www.arpanetwork.io/en-US/randcast.

Alongside the frontend update, new versions of the Playground consumer contracts have been deployed on multiple major blockchain networks, including BSC, Ethereum mainnet, Base, Optimism, Taiko, and the Ethereum Hoodi testnet. These deployments allow users to interact with the Playground directly on their preferred chain while using the same underlying randomness flow and contract logic.

In practice, the Playground is designed to remain lightweight and responsive. Randomness requests are typically fulfilled within around ten seconds, which makes it suitable for live community activities such as lotteries or draws. The cost model is intentionally simple: users pay only for the randomness request transaction, while response callbacks from the trial subscription are free. This helps lower the barrier for experimentation and repeated use.

The upgraded Playground also supports multiple randomness modes that reflect common real-world scenarios. Users can roll dice, draw winners from a pool of tickets, or perform gacha-style weighted draws. These modes are designed to cover a wide range of community lotteries and gaming mechanics without requiring custom contract deployment.

Each randomness request can include an optional message. In practice, this message is often used to store a Merkle root of a ticket list or participant dataset. While the full list remains off-chain, committing its Merkle root on-chain allows results to be publicly verified after the draw, helping improve transparency and fairness in community use cases.

All of the Playground’s consumer logic is open source and available at https://github.com/ARPA-Network/Randcast-User-Contract. This allows developers to audit the contracts, understand how Randcast is integrated in practice, and reuse or adapt the code for their own applications.

SharedConsumer: A Deployed Randomness Consumer Contract

At the center of the Randcast Playground is a contract called SharedConsumer. SharedConsumer is a ready-to-use randomness consumer built on Randcast and deployed across all supported Playground networks.

The contract is intended to serve two purposes. For communities, it provides an immediate way to run fair lotteries or random draws without deploying custom contracts. For developers, it acts as a reference implementation that shows how Randcast can be integrated into a consumer contract in practice.

SharedConsumer is open source and available at: https://github.com/ARPA-Network/Randcast-User-Contract

Rather than abstracting away implementation details, the contract exposes how randomness requests are submitted, how fulfillment callbacks are handled, and how subscriptions are managed across different request types.

Supported Randomness Workflows

SharedConsumer supports three primary randomness workflows that reflect common patterns in community and gaming applications.

The first workflow is ticket drawing. In this mode, a specified number of winners is selected from a pool of tickets, with an upper limit of 1,000 total tickets. This pattern is commonly used for community giveaways, airdrops, and contest-style selections. Once a request is made, the contract emits an on-chain event recording the parameters of the draw, followed by a result event that includes the winning ticket indices after randomness is fulfilled.

The second workflow is dice rolling. This allows multiple dice rolls to be performed in a single request, with configurable dice sizes. Up to 100 rolls can be included in one request, making this mode suitable for simple games, simulations, or general-purpose random number generation. The results are returned as indexed values and emitted on-chain for later inspection.

The third workflow is gacha, which introduces weighted random selection with rarity tiers and upper limits. Each request defines a set of weights that determine how often each tier is selected, along with index ranges that map to specific items. For each draw, the contract emits both the selected tier and the final item index, allowing the randomness process to be verified and audited.

To align with user expectations, indexing starts from 1 across all modes. Across all three workflows, requests and results are linked by a request ID, ensuring a one-to-one correspondence between each randomness request and its fulfillment. Together, these design choices help maintain consistency between displayed results and on-chain events, enabling users to independently verify outcomes on-chain.

Subscription Handling and Cost Model

SharedConsumer supports both trial subscriptions and user-provided subscriptions. In the context of the Randcast Playground, a trial subscription is used so that users only need to pay for the randomness request transaction. The gas cost associated with randomness verification and callback execution is covered by the trial subscription.

This setup is intended to demonstrate how Randcast’s subscription mechanism works while keeping the Playground accessible for experimentation and repeated use. Developers integrating Randcast into their own contracts are not limited to this model and can manage subscriptions directly based on their application’s requirements.

Contract Design and Architecture

From an architectural perspective, SharedConsumer is designed to handle multiple randomness request types within a single consumer contract. It builds on the Randcast consumer base and incorporates standard upgradeability and access-control patterns.

The contract is upgradeable using the UUPS pattern and includes ownership-based administrative controls. It also demonstrates how to dynamically estimate callback gas requirements and handle fulfillment logic in a way that is compatible with Randcast’s two-phase request and fulfillment lifecycle.

For developers, this makes SharedConsumer a practical reference not just for randomness usage, but also for structuring consumer contracts that need to handle asynchronous callbacks and subscription-based costs.

Using the Playground in Practice

For communities, the Randcast Playground provides a way to run transparent randomness processes without deploying custom contracts. Users can select a network, choose a randomness mode, submit a request through the Playground’s command-style interface, and observe the result once it is fulfilled.

For developers, the Playground offers a live environment where deployed contracts, real transactions, and on-chain events can be observed. Studying how SharedConsumer behaves in production-like conditions can help inform design decisions when building custom consumer contracts.

A recent example of community usage is the RaveDAO Genesis Rewards Raffle, which used Randcast Playground on BNB Chain to run a gacha-style weighted draw. The raffle relied on on-chain verifiable randomness to ensure that selections were transparent and could not be influenced or manipulated, including by the organizers themselves. The execution was publicly shared by the community for verification.

https://x.com/RaveDAO/status/2002306760552702427?s=20

In this raffle, every Genesis NFT holder was automatically included. Each NFT represented one raffle entry, with selection odds weighted by tier. Higher tiers received higher weights, while all tiers remained eligible. Members holding passes across multiple tiers participated independently in each eligible tier.

The selection followed a two-step weighted randomness model. First, a weighted draw determined which tier would receive a prize. Second, a winner was randomly selected from within that tier. This structure matches the weighted randomness pattern supported in the Randcast Playground’s gacha mode, where category selection precedes final result selection and outcomes can be audited on-chain.

Closing Thoughts

Randomness is one of those primitives that often fades into the background until something goes wrong. In decentralized systems, getting it right is not just about producing a number, but about making the entire process transparent, verifiable, and understandable to anyone who chooses to look closer.

The Randcast Playground is not designed to hide this complexity. Instead, it aims to make it easier to engage with directly. By working with real contracts, real transactions, and real on-chain results across multiple networks, the Playground offers a practical way to observe how verifiable randomness behaves in live environments rather than in abstract examples.

For some, the Playground may simply be a convenient way to run a transparent draw or community lottery. For others, it may serve as a first step toward understanding how verifiable randomness can be integrated into more complex applications and systems. In both cases, the intent is the same: to reduce the distance between learning, experimenting, and building responsibly on-chain.

As always, users are encouraged to read the code, understand the assumptions being made, and test thoroughly. The Playground is not meant to be an endpoint, but a place to explore, one that reflects how Randcast operates in practice and where clearer designs, better questions, and more informed decisions can begin.

About ARPA

ARPA Network (ARPA) is a decentralized, secure computation network built to improve the fairness, security, and privacy of blockchains. The ARPA threshold BLS signature network serves as the infrastructure for a verifiable Random Number Generator (RNG), secure wallet, cross-chain bridge, and decentralized custody across multiple blockchains.

ARPA was previously known as ARPA Chain, a privacy-preserving Multi-party Computation (MPC) network founded in 2018. ARPA Mainnet has completed over 224,000 computation tasks in the past years. Our experience in MPC and other cryptography laid the foundation for our innovative threshold BLS signature schemes (TSS-BLS) system design and led us to today’s ARPA Network.

Randcast, a verifiable Random Number Generator (RNG), is the first application that leverages ARPA as infrastructure. Randcast offers a cryptographically generated random source with superior security and low cost compared to other solutions. Metaverse, game, lottery, NFT minting and whitelisting, key generation, and blockchain validator task distribution can benefit from Randcast’s tamper-proof randomness.

For more information about ARPA, please contact us at contact@arpanetwork.io.

Learn about ARPA’s recent official news:

Twitter: @arpaofficial

Medium: https://medium.com/@arpa

Discord: https://dsc.gg/arpa-network

Telegram (English): https://t.me/arpa_community

Telegram (Turkish): https://t.me/Arpa_Turkey

Telegram (Korean): https://t.me/ARPA_Korea

Reddit: https://www.reddit.com/r/arpachain/

Dear ARPA community,

As we settle into the new year, the momentum at ARPA Network continues to accelerate. This winter has been defined by the strategic expansion of our Verifiable AI Framework, significant technical upgrades to the Randcast Playground, and a deepening of our ecosystem partnerships. From launching major privacy-preserving frameworks to maintaining billions in TVL, ARPA is steadfast in its mission to build a more secure, verifiable, and decentralized future. Thank you for your continued support! Here is what we have been building and launching since our previous update.

Tech Upgrades: Strengthening the Foundation

This winter brought crucial enhancements across the ARPA stack, focusing on developer experience and network robustness:

Randcast Playground Enhancements: We have significantly improved the Randcast Playground to better serve developers. Updates include the addition of a Gacha Action Type, improved support for Weighted Draw and Merkle Roots, and a more seamless Network Switch experience.

Network & Protocol Updates: The BLS-TSS-Network has been adapted to Alloy from Ethers-rs, optimizing performance and compatibility. We also added support for HTTP Polling for listening to contract events, streamlining integration for dApps.

Expanded Testnet Support: To support broader testing environments, we have officially rolled out support for the Hoodi Testnet and Taiko Hoodi Testnet.

ARPA AVS Growth Metrics

Total Value Locked (TVL): $4.9 Billion

Number of Stakers: 68.8K

Number of Operators: 14

Strategic Integrations & Ecosystem Partnerships

We have strengthened our ecosystem through high-impact collaborations that leverage ARPA’s verifiable infrastructure for real-world utility:

Launch of Verifiable AI Framework: A major milestone this season was the official launch of our Verifiable AI Framework using Zero-Knowledge Proofs (ZKPs). This initiative brings trustless, privacy-preserving AI verification to sectors like identity, analytics, and gaming.

Featured on Coinmarketcap and Business Insider.

ARPA x PredX: We partnered with PredX, a Solana-native AI prediction market, to provide verifiable randomness and secure computation. This collaboration extended into a community challenge centered on the theme “What’s Verifiable AI to You?” to engage the ecosystem in critical conversations.

New Partnership with Vapor: We are excited to partner with Vapor, a leading non-custodial Ethereum staking platform, to explore how ARPA’s privacy-preserving computation can enhance the next wave of AI-powered DeFi services.

Ongoing AVS Collaborations:

Blockscape Partnership: We continue to cooperate closely with our AVS operator Blockscape. As ARPA rolls out various updates, Blockscape maintains robust and secure operations.

Nodes.Guru Partnership: As we implement upgrades, Nodes.Guru continues to ensure high-performance operations while exploring synergies to strengthen the decentralized infrastructure layer.

EigenYields Partnership: Our close partnership continues to fortify AVS stability, decentralization, and operator performance as we roll out technical enhancements.

Randcast Powers RaveDAO: ARPA Randcast powered the RaveDAO Genesis Rewards Raffle, bringing verifiable, on-chain randomness to the world’s first on-chain entertainment network.

Thought Leadership & Media

Our leadership and research teams have been active in driving the global narrative around Zero-Knowledge technology and Verifiable AI:

OpEd on CoinDesk: Our CEO Felix Xu published an OpEd titled “Zero-Knowledge Tech Is the Key to Quantum-Proofing Bitcoin,” breaking down why ZK tech is essential for safeguarding Bitcoin against future threats.

Read it here on Coindesk

Hackernoon Feature: Felix also explored trustless inference and algorithmic proofs in his piece “Why AI Must Learn to Verify Itself,” highlighting ARPA’s role at the forefront of verifiable AI research.

Check it out on Hackernoon

Educational Guides & Articles:

Crucial Role of Privacy in Web3: We offer an analysis of how the concept and importance of privacy has evolved over time from Web1 to Web3. Through an overview of privacy preservation technologies and networks, this guide demonstrates why privacy-preserving blockchains are a comprehensive solution for future internet users.

Evolution of Privacy-Preserving AI: We published an overview on the evolution of privacy preservation technology during the age of AI. It analyzed the paradigm shift of privacy from Web2 to Web3, and also provides a forecast of major shifts that will occur in 2026 in regards to privacy technology.

ZKML Guide for Beginners: We released a newcomer-friendly guide to Zero-Knowledge Machine Learning, explaining where cryptography and AI converge to redefine trust in Web3.

Privacy-Preserving AI: Our latest article dives into how privacy AI and zk-SNARKs combine to create trustworthy, verifiable AI systems. It also delves into an outlook on privacy tech going into 2026.

Research Series: We published deep dives into demonstrating AI model accuracy through Zero-Knowledge Proofs and ZK-SNARK Verifiable Machine Learning.

Demonstrating AI Model Accuracy: Showcased how zero knowledge proofs can be used to prove AI models and often can perform better than direct computation.

ZK-SNARK Overview: Deep research piece delving into the programmability and composition of ZK-SNARKs, including their potential application in verifiable machine learning.

Looking Ahead

As we move further into 2026, ARPA Network is poised for continued growth. With the launch of our Verifiable AI Framework and a robust suite of partnerships, we are more committed than ever to powering the infrastructure of a decentralized, privacy-preserving world. Thank you to our partners, our operators, and most importantly our community for continuing to be a part of this journey!

About ARPA

ARPA Network (ARPA) is a decentralized, secure computation network built to improve the fairness, security, and privacy of blockchains. The ARPA threshold BLS signature network serves as the infrastructure for a verifiable Random Number Generator (RNG), secure wallet, cross-chain bridge, and decentralized custody across multiple blockchains.

ARPA was previously known as ARPA Chain, a privacy-preserving Multi-party Computation (MPC) network founded in 2018. ARPA Mainnet has completed over 224,000 computation tasks in the past years. Our experience in MPC and other cryptography laid the foundation for our innovative threshold BLS signature schemes (TSS-BLS) system design and led us to today’s ARPA Network.

Randcast, a verifiable Random Number Generator (RNG), is the first application that leverages ARPA as infrastructure. Randcast offers a cryptographically generated random source with superior security and low cost compared to other solutions. Metaverse, game, lottery, NFT minting and whitelisting, key generation, and blockchain validator task distribution can benefit from Randcast’s tamper-proof randomness.

For more information about ARPA, please contact us at contact@arpanetwork.io.

Learn about ARPA’s recent official news:

Twitter: @arpaofficial

Medium: https://medium.com/@arpa

Discord: https://dsc.gg/arpa-network

Telegram (English): https://t.me/arpa_community

Telegram (Turkish): https://t.me/Arpa_Turkey

Telegram (Korean): https://t.me/ARPA_Korea

Reddit: https://www.reddit.com/r/arpachain/