What Are Rollups-as-a-Service and Appchains?
Written by Vinny Mullin
Reviewed by Alchemy
Introduction
Customized blockchains have evolved from a theoretical concept of Ethereum’s scaling roadmap into a core product option for web3 apps and chains looking to grow within the EVM ecosystem.
When choosing to build within the EVM ecosystem, web3 projects are increasingly choosing to deploy a customized blockchain. Customized blockchains enjoy the decentralization and security benefits of Ethereum, while providing increased performance and scalability that isn’t available when building directly on Ethereum.
Within customized blockchains, infrastructure providers often offer two approaches: appchains and rollups. Although appchains and rollups are similar in concept, providers, and tech stack, there are essential considerations that a project should consider before choosing an approach and provider.
This guide will provide a thorough understanding of the benefits and tradeoffs of deploying an appchain or a rollup, outline the technical requirements to launch a customized blockchain, and explore the different approaches that web3 teams can take when choosing a provider for their customized blockchain infrastructure.
Custom Blockchains 101: Understanding Appchains and Rollups-as-a-Service (RaaS)
Appchains
An appchain is a blockchain built specifically to support a single application, rather than hosting many apps like a general-purpose public blockchain.
By design, appchains give web3 developers full control over their app’s infrastructure. They can customize the economic model, governance system, and consensus algorithm to fit their exact needs. In contrast, apps built on shared public blockchains must compete with others for limited resources like compute and storage.
This independence allows projects to fine-tune every layer of their stack—from performance and gas efficiency to developer permissions and community engagement. The result is often better performance and a stronger, more aligned user base.
Appchain customizations may include higher Transactions Per Second (TPS), increased gas throughput (measured in Mgas/s), tailored security models, and permissioned access for developers or users. Projects like dYdX and Secret Network have boosted performance by migrating to their own appchains.
When choosing between an appchain and a rollup, the key question is whether your chain should be purpose-built for your app alone, or flexible enough to support multiple apps, developer teams, or communities.
Keep in mind: ‘appchain’ is a broad term. It can refer to various setups across different ecosystems. One appchain might be a sovereign Layer 1 built with the Cosmos SDK, while another could be an app-specific rollup deployed through Alchemy’s Rollups-as-a-Service (RaaS) platform.
Rollups-as-a-Service (RaaS)
A rollup is a type of customized blockchain that enhances Ethereum’s scalability by shifting computation and data storage offchain. This significantly improves throughput and reduces latency on Ethereum’s base layer. Unlike appchains, rollups are not limited to a single application—they can support multiple apps and user groups within a shared ecosystem.
Rollups can also be app-specific, effectively serving as a type of appchain. Depending on the project’s technical requirements or preferred blockchain stack, a team may choose to launch an app-specific rollup using a Rollups-as-a-Service (RaaS) provider.
Rollups-as-a-Service (RaaS) providers streamline the rollup deployment process. By offering pre-built frameworks, SDKs, and managed infrastructure, RaaS platforms allow teams to focus on ecosystem development rather than the complexities of chain deployment.
Key benefits of rollups include:
Custom chain configuration — fine-tune block time, gas throughput, transactions per second (TPS), and more
Sequencer control — implement shared or decentralized sequencing to give the rollup’s community more economic ownership
Monetization potential — capture transaction volume and turn it into revenue
Expanded block space — allocate dedicated block space to your ecosystem, keeping user gas costs low
When launching a rollup, developers must choose the right deployment framework. Options like Optimism’s OP Stack, Arbitrum Orbit, and zkSync’s ZK Stack each offer unique technical advantages and tradeoffs.
While both rollups and appchains enable customization beyond what’s possible on public blockchains, the choice depends on your goals—whether you want a general-purpose environment or something app-specific.
In either case, teams without deep infrastructure experience should strongly consider using a provider to ensure a secure, scalable, and reliable deployment.
Next, we’ll explore the technical components required to launch either an appchain or a rollup.
The Essential Toolkit to Deploy and Grow a Custom Blockchain
Custom blockchains share similar infrastructure requirements as public blockchains like Ethereum, Base, ZKsync and others. If you’re interested in deploying your own custom chain, you’ll need to have reliable solutions for each of the following:
Scalable RPC Node Infrastructure
A Remote Procedure Call, or RPC, Node, is a lightweight software communication protocol for users to read and write from your blockchain. RPC Nodes must scale continuously with your app or chain in order to maintain performance. It is possible to run your own RPC node but this choice comes with engineering and knowledge requirements.
High-Availability Sequencer
A sequencer is an entity responsible for ordering and bundling user transactions into batches before submitting them to the Layer 1 (L1), parent blockchain. Sequencers take on additional responsibilities depending on the type of rollup, such as generating and publishing state roots in optimistic rollups, or using separate sequencers for ordering transactions and generating validity proofs in ZK-rollups. Rollup designs are increasingly moving toward decentralized sequencer networks rather than single entities to improve security and censorship resistance. Sequencing is a critical element in the appchain/rollup toolkit, with significant performance and security downside if it stops functioning properly.
Smart Wallets to Secure Assets
Smart wallets are applications built on top of your chain that leverage Account Abstraction to create better user experiences while maintaining security. Unlike traditional EOA wallets, smart wallets can offer features like social recovery, session keys, batched transactions, and gasless interactions. They provide a web2-like login experience to simplify onboarding new users, while still securing users' funds with blockchain-native security. Adding mart wallet support to your appchain or rollup is an essential differentiator that can help improve adoption and retention by blurring the lines between web2 and web3 experiences.
Block Explorer
A block explorer is a tool to provide easy, transparent access to your appchain or rollup’s data. Providing an always-on explorer where users can intuitively discover information about your customized blockchain is critical to maintaining a healthy, trusting user base.
Bridges, On/Off-Ramps and Tools for Cross-Chain Interoperability
When launching a new blockchain, you'll need to provide secure, usable tools that grow onchain liquidity and allow users to move funds. While traditional bridges have enabled asset transfers, they also represent significant security risks. (Over $2 billion has been lost in bridge hacks since 2021!) Native interoperability protocols have helped fix these issues, especially when backed by rigorous security audits. Additionally, fiat on/off-ramps are crucial for mainstream adoption. While the Layer 2 ecosystem continues to evolve interoperability standards, providing secure bridges or other cross-chain tools will allow your chain's liquidity to safely grow.
Testnets, Faucets and Other Developer Tool Solutions
The ‘toolkit’ of the customized blockchain toolkit. Testnets, faucets and other developer tools are essential for testing your blockchain, integrating new projects and builders before a mainnet launch, driving user growth, and more. Testnets provide a risk-free environment for developers to build and test applications before deploying to mainnet. Faucets distribute testnet tokens to developers, enabling them to test transaction flows without real financial risk. These tools are often an afterthought, but require consistent maintenance in order to function properly.
How Alchemy Supports & Deploys Appchains and Rollups
We support and deploy both appchains and rollups through Rollups, our RaaS offering. For more details about our complete RaaS offering, click here.
We help developers deploy and scale enterprise-grade appchains and rollups, providing a complete solution for teams that need more than a self-serve devnet or testnet. With our scalable infrastructure and built-in developer tools, we deliver a white-glove builder experience that handles your chain’s requirements end-to-end.
Deploying your chain through Rollups immediately enables our reliable, scalable RPC Node infrastructure and 10+ APIs, Smart Wallets, and more, all instantly installed on your chain. Your customized blockchain’s performance benefits from:
Subgraphs – enabling powerful data indexing for your users
Multi-Chain Data APIs – powering token history, NFT calls, and transaction simulations
Custom Webhooks – delivering real-time data on any event across any blockchain
We’ve spent over 7 years running chain infrastructure for the biggest projects in web3, and developers interested in either an appchain or rollup can leverage this same infrastructure and expertise for their customized blockchain.
Whether you’re building an onchain gaming app with ultra-high performance requirements or a DeFi protocol optimizing monetization, choosing between an appchain and a rollup is a critical decision.
By partnering with providers specializing in customized blockchain deployments, teams can focus on growing their ecosystems while ensuring their infrastructure scales effectively.
Getting Started with Custom Solutions from Alchemy RaaS
If you're ready to deploy a production-grade appchain or rollup, contact our team. Our Product and Engineering teams will collaborate closely with you to define your specifications, customize solutions, and optimize infrastructure choices.
FAQ
What is Rollups-as-a-Service (RaaS)? RaaS providers manage the entire rollup deployment process by building and managing a rollup’s infrastructure stack, allowing teams to focus on ecosystem development rather than chain complexity.
What is the difference between an appchain and a rollup? An appchain is a blockchain built specifically for a single application with full control over governance and infrastructure, while a rollup enhances Ethereum's scalability by shifting computation offchain and can support multiple apps.
When should I choose an appchain versus a rollup? This nuanced question depends on whether your chain should be purpose-built for your app alone (appchain) or flexible enough to support multiple apps, developer teams, or communities (rollup). Teams can also choose from an app-specific rollup (often referred to as an appchain) rather than launching a custom L1 or sidechain. If you’re not certain, ask your RaaS provider for advice.
What are the benefits of using RaaS instead of building from scratch? Teams without deep infrastructure experience can ensure secure, scalable, and reliable deployment through a RaaS provider, enabling customization beyond public blockchains without the complexity of building from scratch.
