The Open House NYC online Buildathon ran from February 5 to February 26, 2026, functioning as the first phase of a four-city global competition with an $800,000 total prize pool across editions in New York, Dubai, London, and Singapore, a figure previously reported in earlier coverage of the series. Three teams took home awards from the NYC phase: Tilt Protocol ($15,000), Fangorn ($10,000), and EqualFi ($5,000). The competition then moved to an in-person Founder House held March 6 to 8, which offered up to $340,000 in additional prizes and grants.

Grant Program and Sponsor Lineup

The Arbitrum DAO committed $6.75 million through its DDA 3.0 program (also referred to in Arbitrum governance forums as the D.A.O. Grant Program Season 3; the full expanded program name has not been independently confirmed at time of publication), structured across five categories: New Protocols, Dev Tooling, Gaming, Education and Events, and Orbit Campaigns (each receiving $1.5 million except Orbit Campaigns, which received $750,000). The $6.75 million figure appeared in Arbitrum's official announcement, though an independently confirmed completed governance vote was not available in public records at time of writing; readers should treat the commitment as reported pending final DAO confirmation. Orbit refers to Arbitrum's framework for building customized Layer 2 or Layer 3 chains on top of Arbitrum's technology.

Sponsors for the NYC buildathon included Robinhood Chain, LayerZero, OpenZeppelin, Alchemy, GMX, Fhenix, and Dune. Robinhood Chain's participation carries specific significance: the company launched a public testnet for its Arbitrum-based blockchain on February 10, 2026, five days after the buildathon opened. The testnet recorded four million transactions in its first week and supports tokenized versions of equities including Tesla, Amazon, Palantir, Netflix, and AMD as test assets. Robinhood has committed $1 million in prizes spread across all four Open House cities. The company has described its goal as accelerating the development of onchain financial services, with the Arbitrum Orbit stack enabling EVM compatibility and custom gas token support. No mainnet launch date has been announced.

Fhenix, another sponsor, develops fully homomorphic encryption (FHE) tools for the EVM. FHE allows smart contracts to compute on encrypted data without decrypting it at any point, a property with applications in private DeFi and compliant financial products. Fhenix's CoFHE coprocessor is already live on Ethereum mainnet and Arbitrum, including Arbitrum Sepolia, grounding these capabilities in deployed production infrastructure rather than theory alone. Fhenix has raised $22 million in funding, including a $15 million Series A.

Client Diversity and Uniswap Integration

On the infrastructure side, the Arbitrum Foundation confirmed that Nethermind successfully synced the Arbitrum Nitro plugin on Arbitrum Sepolia (a test network) in archive mode. Archive mode stores the complete history of blockchain state, which is essential for data indexers and analytics providers. The sync supports Stylus execution, Arbitrum's multi-language smart contract environment, and all upgrades through ArbOS Dia (the latest ArbOS release, which introduces fee smoothing during network congestion spikes, passkey-based onboarding, new interoperability token standards, and Ethereum Fusaka compatibility). Arbitrum has historically depended on a single Geth-based client; adding Nethermind and Erigon as alternatives reduces the risk that a bug in one piece of software could affect the entire network.

Uniswap Labs deployed its Continuous Clearing Auctions (CCA) tool on Arbitrum One. The standard approach to launching a new token involves creating a liquidity pool and opening trading immediately, which creates an opening for automated bots that purchase tokens ahead of regular users and resell at a markup (a practice called MEV, or maximal extractable value). CCA replaces that process by accepting bids capped at a maximum price and clearing them block by block, gradually establishing a fair market price before automatically seeding liquidity on Uniswap V4. The tool is free and permissionless. Uniswap Labs described the mechanism as providing "onchain-native market creation, more fair and gradual price discovery, as well as automatic liquidity seeding on Uniswap V4." Platforms including HuddlePad have already adopted it as a default launch tool.

Also notable from this period, Privara, a privacy-payments application, launched on testnet. The project fits within a broader pattern of privacy-focused infrastructure development on Arbitrum, alongside Fhenix's FHE coprocessor work described above.

Market Context

ARB, Arbitrum's governance token, traded at approximately $0.10 as of mid-March 2026, with a market capitalization of roughly $620 million and a circulating supply of about 5.2 billion of 10 billion total tokens. These figures are drawn from data dated March 9 to 13, 2026, and are highly time-sensitive; current values should be verified via CoinGecko before publication. The token posted a 7-day gain of approximately 4.8 percent against a broader market move of around 0.5 percent. Total value locked (TVL) on Arbitrum stood at approximately $2 billion in early March 2026, based on data dated March 9, 2026, and should be verified via DefiLlama before publication.

TVL declined sharply from a reported peak of $16.6 billion in November 2025. That decline reflects a combination of broader DeFi market contraction, intensifying competition from other Layer 2 networks including Base, and potentially methodological differences in how TVL is measured across different time periods. That last factor is a relevant caveat for any comparison drawn from a single API snapshot rather than a consistent longitudinal methodology.

Regional Implications

For builders in South Asia and Africa, several of these updates carry direct relevance. The $1.5 million Education and Events category within DDA 3.0 is a primary candidate for funding regional developer programs, based on the category's stated mandate, though the Arbitrum Foundation has not made a direct public statement linking those funds to specific regional pipelines. Arbitrum's HackerBoost programme, run by DeFi Africa with Arbitrum grant support, trained more than 450 builders across the continent and produced seven minimum viable products on Arbitrum Sepolia, two of which reached production-ready status. Arbitrum's fee structure held at a median of $0.20 during a market event that caused $220 billion in liquidations, compared to $8.66 on Ethereum mainnet and $0.61 on competing Layer 2 networks during the same period. That cost advantage makes the network viable for low-value transactions including remittances common in these markets. The CCA tool addresses a specific pain point for smaller token projects in emerging markets, where MEV bot activity at launch can be particularly damaging relative to available liquidity; that pattern is an editorial inference drawn from the tool's design rationale rather than a directly cited empirical finding.

South Asia has also seen sustained Foundation engagement. The Bengaluru IRL Hacker House produced three prize-winning projects: Orbital AMM Protocol, Shinobi.Cash, and GuardChain.ai. Aditi Chopra, Arbitrum Foundation India Regional Growth Lead, has spoken publicly about the Foundation's commitment to the Indian developer ecosystem, and the appointment of a dedicated India regional lead reflects an ongoing organizational investment in the region rather than episodic event sponsorship.

The Singapore Open House edition, scheduled for later in 2026, will offer the next direct on-ramp for South and Southeast Asian founders into the broader competition series.