Halliday: The First Workflow Protocol

As blockchain has scaled, a mass proliferation of infrastructure, chains, and on-chain services has ensued.

Large acquisitions have paved the way for enterprise adoption of public blockchains.

Strong AI is a reality now, with its effects rippling through industries. The launch of reasoning models make it inevitable that AI agents will perform important actions on our behalf.

But this explosion of progress has created a wall of complexity. It’s too difficult to ship blockchain products. The thousands of chains and services coming online have burdened developers with unending plumbing work. Building smart contracts, or as we call them application-specific integrated protocols (ASIPs), for every new use case is no longer tenable — there’s a better way.

Smart contracts are obsolete

Smart contract development is slow, expensive, and dangerous. Unlike traditional software, once you deploy a contract on-chain, it’s difficult to iterate:

• 6–12+ months to add functionality.
• Expensive audits required, even for minor changes.
• Non-battle-tested contracts are susceptible to deadly exploits.

Whenever a customer requests something new, you’re stuck saying “Wait months for an audited update” — often losing deals in the process. This is the cost of building ASIPs.

Integrations never end

The current stack is overwhelming. Developers are faced with unending integration work. In building Halliday, we were tasked with integrating ninety components (DEXs, bridges, networks, customer protocols, etc.). An integration optimistically takes three weeks, adding up to five years of engineering time — time diverted from building core business logic.

Composing existing integrations is difficult

Moving data between heterogeneous protocols is hard and building the supporting infrastructure for reliable execution is even harder.

This requires a system that is fault-tolerant under failure modes. Errors like gas fee spikes, bridge outages, or arbitrary contract reverts are common when working with numerous components. Maintenance also demands constant time and effort: protocols migrate from V1 to V2, data APIs change formats, etc.

Building multi-chain adds significant complexity

In recent years, it has become essential to support alt-VMs, such as Solana, TON, and SUI. Even though there are fewer VMs than on-chain services, each new VM can add 6–12+ months of development time and a maintenance burden.

Handling hundreds of chains makes all of the above more complicated. You need deployment ops, data systems, reliable execution, and monitoring on every chain. Augmenting a system to handle this adds 12+ months. Halliday solves this automatically — no new code required.

Operationalizing AI with on-chain assets is hard

You can’t just hand over your keys and/or assets to an AI system. That is neither safe nor compliant. However, to make AI useful for blockchain apps agents need to be able to work with user assets and perform actions on-chain. You also need to be sure that the AI can’t lose funds, steal assets, or make consequential mistakes. Businesses need to have oversight and control over the scope of actions an agent can perform. For AI to be integrated into real crypto businesses, we need robust safety infrastructure for AI.

This requires a trustless workflow protocol that enables users to leverage AI safely. You need to be able to define tasks and set guardrails that are enforced on-chain. This is a frontier research problem, requiring thousands of hours of R&D and engineering.

We built a workflow engine once, so you never have to write smart contracts again

Everyone thinks you should write smart contracts for every on-chain application. However, most developers aim to stitch together protocols into workflows for specific use cases. Much like how most web2 developers solve problems in high-level scripting languages like JavaScript, the vast majority of web3 use cases don’t require low-level contract code. For most production needs — especially multi-chain/multi-service scenarios — this is especially true.

The cost of working in low-level code is lost customers. We were in a deal discussion and a potential customer asked if we could handle recurring payments across networks. At the time, we supported one-time payments but our smart contracts didn’t support subscriptions. In a high-level programming environment this would have been a trivial addition. Because we were stuck having to re-write smart contracts, we told them we couldn’t support the request for over 6 months. We lost the deal.

What if there was a better way? What if you could outsource most of the work of making a multi-service application? What if a zero-trust platform could integrate, compose, and automate existing protocols on your behalf obviating the need to build custom glue and reliability logic over and over again?

While others focused on liquidity optimizations, we saw that smart contracts were the core issue. Our insight was to build a workflow engine once and never write a smart contract again. An engine eliminates the need to write new smart contracts per use case by handling protocol integration, composition, and automation out of the box.

This workflow engine was the perfect foundation for agents. With it, agents could transform user intention into on-chain action, orchestrate processes, and interact with smart contracts easily. However, to trust agents with crypto assets, there needs to be a way to implement guardrails that guarantee safe task completion.

That’s why we’re excited to introduce the first workflow protocol: a platform that lets you define tasks with immutable guardrails that enables autonomous systems, such as agents or software, to do work for you.

ASIP vs Workflows side-by-side

The first workflow protocol

An workflow is a sequence of tasks with immutable guardrails that lets autonomous systems do work for you.

The workflow protocol saves you 10+ years of engineering time. No need to perform countless integrations. No need to build reliable execution logic. No need to manage complex data systems. Simply put, avoid building over a decade of plumbing infrastructure.

Halliday features a unified programming model, allowing you to write workflows as code. Define workflows in your favorite language and deploy them to Halliday Protocol for guaranteed execution. You only need to learn one protocol, instead of navigating multiple project docs and manually stitching together rigid ASIPs, which is time consuming and error prone.

The protocol is zero-trust which uniquely enables the safe delegation of partial or entire workflows to agents. Guardrails and task objectives are immutable and enforced on-chain. No party, not even Halliday or AI, can circumvent guardrails placed on a task. This is an essential unlock for blockchain businesses who have been eager to integrate AI into their applications.

For the vast majority of work, you’ll never have to write a smart contract again. Workflows can handle a wide variety of tasks, including advanced scheduled and event based actions. Furthermore, Halliday is a general-purpose platform, allowing you to define any flow you’d like.

Define the following with ease:

• A one-time contract call.
• A cross-chain swap.
• A multi-chain recurring payment with smart routing and up-to-date price information.

The magic of all of this is that each workflow, irrespective of the complexity, requires no infrastructure from you.

Workflows are forward-composable. As new protocols, VMs, and chains launch, you do not need to perform integration and infrastructure work to use them. The platform will handle all this work for you. No changes to your code base. No re-architecture. No lost months. Co-evolve with the market.

Build breakthrough apps in hours, not years

Halliday lets you build breakthrough apps in hours not years. Matter of fact, we invite you to re-create many of the core features of our first party product, Halliday Payments, in hours not the years it took us.

Rest easy knowing the technology is already battle-tested. We’ve used a proprietary version of our workflow engine in production for over a year to power payments flows for ApeChain, Avalanche’s Core Wallet, Shrapnel, DeFi Kingdoms, Metis, and more. And, we have upcoming launches with Frax, Lens, Story Protocol, and more leading projects.

With Halliday, there are many use cases that would take years to build as an ASIP that you can now build in hours as a workflow. Build the following in hours, not years:

• Recurring payments
• Liquidity & bridge aggregator
• Event-based or scheduled solver rebalancing
• Cross-chain NFT checkout
• Treasury management
• Yield optimizer

Furthermore, workflows empower you to safely integrate AI into your blockchain business for the first time, enabling agents to perform actions tailored to your app. With Halliday Protocol, maintain full control, observability, and ship agentic blockchain products.

The era of agentic blockchain is now

The blockchain industry has been relatively isolated from AI, until now. It is readily apparent that agents will power the next evolution of software products irrespective of the technology vertical, be it big data, cloud computing, or blockchain.

Don’t stay stuck in two year development cycles as the agentic era dawns. Those who adopt AI in a safe, compliant, and efficient manner will offer superior experiences to their users. The rest of tech has gotten the message and has whole-heartedly embraced AI. Before we know it, the most used products will all be AI-powered or disrupted by AI-native businesses. It’s about time blockchain catches up. Halliday is here to assist, providing the guardrails and protocol needed for a safe and easy integration of AI on blockchain.

Ready to never write a smart contract again?

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Halliday’s Workflow Protocol is rolling out to early access this quarter. Sign up here.

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Try Halliday Payments

To try out our first party product, Halliday Payments, built on the Workflow Protocol, please visit this page or schedule a time to meet with us.

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About Halliday

Halliday is the first Workflow Protocol. Halliday enables you to create breakthrough applications in hours, not years. Halliday Payments, the first-party application built on top of the protocol, streamlines onboarding by enabling users to seamlessly acquire any asset on your chain with just a single click, creating a frictionless user experience.

Backed by a16z and #Hashed, we have partnered with prominent developers such as ApeChain, Story Protocol and DeFi Kingdoms. Our team comes from Stanford, Harvard, and Carnegie Mellon, and has years of experience at the most recognized Web2 and Web3 brands in the world, including Alphabet, Meta, Netflix, Stripe, Compound and more.