Builder's Block #009 - Open House 2026 Locations & ArbOS Dia Upgrade
🧑💻 Open House starts bigger than ever
⚙️ New features with ArbOS Dia Upgrade
🦀 Rust SDK v0.10.0 is live
📣 Announcements
Key updates from the Arbitrum ecosystem and Foundation.
Open House 2026 Launches Globally
Arbitrum's Open House is back, bigger than ever: $800K in prizes, four cities worldwide, designed for serious founders ready to ship real products. First edition: NYC. The online phase starts on January 29th.
ArbOS Dia Upgrade Goes Live
The latest ArbOS Dia upgrade is here, bringing smoother fees during spikes, foundations for massive throughput, passkey onboarding, new interop tokens, and Ethereum Fusaka support. Unlocking faster, more efficient building on Arbitrum.
➡️ Dive into the Upgrade Details
📚 Learn & Build
New learning drops and hands-on resources from across the Arbitrum ecosystem.
Build Your First App on Arbitrum
Hands-on guide for newcomers: Learn step-by-step how to deploy your first Arbitrum app using Vibecoding, specifically for devs who are beginning their journey using the ecosystem's powerful tools.
➡️ Start Building Now
x402 v2: Production-Ready Enhancements
Unlock pay-per-use models: New changes to x402 introduce v2 for agentic payments
- Standardized Network Identity (CAIP-2)
- Inspectable Infrastructure (/supported): Facilitators are no longer "black boxes" that builders must trust blindly.
- Header-First Negotiation: To avoid breaking middleware, proxies, or application logic, payment metadata has moved out of the JSON body, following RFC-6648.
- Strict Idempotency and Verification
- Settlement Lifecycle Hooks: V2 uses EIP-712 typed data for explicit settlement signing
StylusSaturdays: Why learn Stylus in 2026?
Unlock Stylus in 2026: Migrate Solana contracts to Arbitrum effortlessly using StylusPort's handbook.
➡️ Migrate from Solana to Arbitrum
Hardhat + Stylus Support in Development
Unified workflows incoming: CoBuilders is integrating Hardhat with Stylus for seamless Solidity and Rust handling, no more tool-switching for cleaner developer experiences.
🔦 Ecosystem Highlights
Fresh launches and standout threads from around the Arbitrum ecosystem.
Explore Arbitrum Tools on Chain.Love
Discover and compare infra easily: Chain.Love's Arbitrum Toolbox organizes RPCs, indexers, oracles, faucets, and more.
➡️ Upgrade Your SDK Today
Arbitrum Audit Program Open for Applications
Gear up for secure launches: The Arbitrum Audit Program is still live, offering early support for teams planning audits to ship with confidence. Perfect for kicking off 2026 strong.
➡️ Apply for Audit Support Now
ArbiFuel Gas Sponsorship Program
Fuel your builds without the gas hassle: ArbiFuel sponsors fees for early-stage teams to test, deploy, and onboard users.
➡️ Get your gas sponsored
🛠️ Dev Tooling & Infra
Updates to SDKs, CLIs, and developer workflows across the stack.
Stylus Rust SDK v0.10.0 Released
Level up your Rust workflows: The new Stylus Rust SDK introduces stylus-tools for programmatic deployments, activations, and verifications, making CI, tests, and multi-contract pipelines a breeze.
➡️ Check the release details
Erigon Nitro Sepolia Node with ArbOS 51 Dia
Massive efficiency boost: Erigon's stable Nitro Sepolia node supports ArbOS 51 Dia with minimal storage (234GB), concurrent fetching, and snapshots.
➡️ Check the last update
🧵 Forum & Community Discussions
What builders are debating and proposing this week.
DevRel Engineer Roles Open at Arbitrum
Join the team: Arbitrum is hiring DevRel Engineers, including APAC and LATAM-focused positions, for those passionate about supporting builders and creating technical content.
➡️ Apply or Share the Opportunity
Audit Program Transparency Report
Inside the numbers: A detailed look at the Arbitrum Audit Program's first phase, with 11 projects approved from 81 total applications.
➡️ Explore the Report
Arbitrum is Going All In on Youtube and TikTok
In 2026, Arbitrum is expanding beyond the scope of crypto Twitter and bringing you, our community, a variety of much-needed video content on YouTube and TikTok.
In these videos, you can expect insights into ecosystem projects, stablecoins, RWAs, Arbitrum protocol upgrades, and many other exciting topics!
That’s all from Builder’s Block #009. Thank you for reading, and keep building. Arbitrum Everywhere.