Why this thread
This is the first entry in a thread we will keep updating with each meaningful contribution we make to Arbitrum, so the community has a single place to follow our work.
Who is CoBuilders
Founded in 2024, CoBuilders is a Web3 studio that builds and runs experienced, blockchain-native, interdisciplinary teams that help the most impactful decentralized finance projects turn their vision into reality. We have delivered work for and alongside teams like Arbitrum, the Nomic Foundation, OpenZeppelin, CoW Protocol, Tools for Humanity (World), and ZetaChain, among others. On Arbitrum, our focus has been on Stylus tooling. The technology works, but the developer experience around it is still thin, and that is the gap we keep working on.
More about us at cobuilders.xyz.
Our track record on Arbitrum
Two contributions are already live, and two more are in progress.
Live:
- Stylus Cache Manager: an open-source GUI for Arbitrum’s Stylus Cache Manager with automated bidding, monitoring, and notifications. Dedicated entry below.
- Hardhat plugin suite for Stylus: brings the full Stylus lifecycle into Hardhat 3, shipped to npm. Dedicated entry below.
In progress:
We will add dedicated entries here as each one ships.
Beyond code:
- We co-organized Arbitrum Bridge LATAM, a Devconnect side event officially recognized by the Argentine government.
- We have supported Arbitrum’s business development in LATAM, connecting the team with regulators, institutions, and founders across the region. Together with @SeedGov, we convened a private executive dinner during Devconnect that put senior decision makers from Argentine banking, fintech and payments in the room with the Arbitrum team.
Team
The CoBuilders team behind our Arbitrum work:
- Lautaro Solé, CEO, Co-Founder and Product Lead.
- Augusto Collerone, hands-on CTO and Co-Founder.
- Ignacio “Nacho” Fernández Quesada, Blockchain Researcher and Software Engineer.
- JoaquĂn Paz Marchese, Program Manager.
- Leonardo Caniglia, Web3 Finance and Ecosystem Research.
What’s next
We are committed to growing the Arbitrum and Stylus tech stack and to sharing our progress here as we ship. We will keep this thread updated with each new contribution, and we are always open to feedback and collaboration from the community.
Follow us on X (Twitter) at CoBuilders (@cobuildersxyz) / X and on LinkedIn at CoBuilders | LinkedIn.
1 Like
A GUI for the Stylus Cache Manager
TL;DR
During the Stylus Sprint, we designed, built, and deployed to mainnet an open source GUI for Arbitrum’s Stylus Cache Manager. It combines on chain bidding automation, a monitoring and notifications backend, and an analytics frontend, so teams can keep their Stylus contracts cached without babysitting the process. Live at stylus.cobuilders.xyz.
The problem
Stylus contracts can be cached onchain to execute cheaply. The Cache Manager governs that cache through a bidding mechanism: contracts bid for cache slots, and when a slot is reclaimed, one or more contracts can be evicted, after which calling them costs significantly more gas. Staying cached is ongoing operational work: teams have to monitor their contracts, watch for evictions, and rebid at the right time. Done manually, it is easy to forget, and users pay for it in gas.
What we built
We turned that low-level mechanism into a full product:
- A monitoring and notifications backend that tracks the on-chain state of every Stylus Cache Manager contract, persists per user data, and sends alerts (for example on eviction) through Slack, Telegram, and webhooks.
- On chain bidding automation: a smart contract that automates re bidding, with automation agents and a custom Escrow (adapted from OpenZeppelin’s) that handles user funds safely, supporting partial withdrawals and authorized calls.
- An analytics frontend with a dashboard, a bid explorer, manual bidding, automation controls, and notification preferences.
Validation
We hardened it with a public beta, gathering feedback from real users and shipping the improvements that mattered most before the mainnet release.
Status: shipped and live on mainnet
Try it
1 Like
Bringing the full Stylus lifecycle into Hardhat
TL;DR
We shipped @cobuilders/hardhat-arbitrum-stylus. A Hardhat 3 plugin suite that brings the entire Stylus lifecycle (compile, test, deploy, local node) into Hardhat. It auto-detects contract type (EVM vs WASM) and lets Solidity and Stylus contracts compile, deploy, and test together in the same project. Available on npm.
The problem
Today, Stylus development requires separate tooling (the cargo-stylus CLI plus nitro-devnode) that lives outside the standard Solidity and Hardhat workflow. For teams building mixed Solidity + Rust projects, this creates four concrete problems:
- A fragmented developer experience across two toolchains.
- Harder CI/CD integration.
- Higher onboarding friction for Solidity teams.
- Audit and reproducibility pain for security reviewers, who face an unfamiliar pipeline.
What we built
A plugin suite built on Hardhat 3, following the same pattern ashardhat-toolbox-viem: one main plugin that bundles four composable sub-plugins, installed with a single import. It exposes a unified, namespaced command surface:
arb:node starts a local Arbitrum nitro-devnode (Docker) with Stylus infrastructure pre-deployed and pre-funded accounts.arb:compile runs dual compilation, Solidity via solc and Rust via cargo-stylus. Stylus contracts are auto-detected by scanning for a Cargo.toml with Stylus dependencies.arb:deploy Deploys both EVM bytecode and Stylus WASM and handles Stylus activation automatically.arb:test Orchestrates the full flow (start node, compile, deploy, test) and runs cross-VM tests where Solidity and Stylus call each other.
How it works under the hood
Compilation produces a manifest.json. That tags every contract as EVM or WASM. The deploy step reads that manifest to auto-select the right deployment path, which is what makes mixed Solidity + Stylus deployments work in a single command. Stylus contracts also need on-chain activation after deployment: the plugin does this automatically (deploy the WASM, call the activation step, wait for confirmation), so it stays invisible to the developer. It is all wired through Hardhat 3’s hook system, network hooks extend network.connect() with Stylus helpers, and config hooks validate and resolve the stylus, arbNode, and arbTest config sections. The suite is a pnpm monorepo published to npm under the @cobuilders scope.
Why it matters
The suite enables cross-VM testing from Hardhat, enabling teams to adopt Stylus incrementally by adding a single performance-critical Rust contract without requiring developers to adopt an entirely new workflow. Same commands, same config, same test suite. And because the pipeline stays familiar, audits and reproducibility get easier for security reviewers too. It lowers the barrier to Stylus for the entire Hardhat community.
Try it
Built with support from the Arbitrum DAO Grants Program. Feedback welcome; this is built for the community.
2 Likes
nice work shipping a Hardhat‑native Stylus lifecycle this is the kind of DX work that actually moves adoption. Next step I’d love to see is hard numbers and case studies: who is using it in production, how it fits into CI/CD, and what auditors think. That evidence will turn this from “great tooling” into a clear DAO public good.
