Sui's Hashi protocol, whose name references the Japanese word for "bridge," launched its public testnet on July 22, 2026, marking the first open testnet access for developers, custodians, and DeFi applications to test a system that lets Bitcoin holders borrow against their holdings without converting or moving their BTC to another chain. The protocol's devnet first went live in March 2026, giving some builders early access before this public opening.

The launch is a significant step for the broader Bitcoin finance category, which now secures tens of billions of dollars in value according to eco.com's BTCfi analysis from mid-2026, and it arrives as Bitcoin's market capitalization sits above $1 trillion.

Hashi works by generating a two-of-two multisig deposit address on the Bitcoin network. When a user sends BTC to that address, Sui validators running Hashi nodes confirm the deposit and mint a corresponding token called #BTC on Sui. That token can then be used as collateral inside Sui-based lending protocols. When the user repays their position, the original BTC is released back to them through a cryptographic process called MPC threshold Schnorr signatures. The BTC never moves to Sui and no centralized custodian holds it. A secondary layer called the Guardian runs inside a secure enclave and acts as a final checkpoint before any Bitcoin release, specifically to reduce the risk of validator collusion or systemic compromise.

If the Guardian goes offline, a taproot-style time-lock mechanism returns funds to the validator committee automatically, so availability is not sacrificed for security.

The contrast with existing wrapped Bitcoin products is meaningful. Solutions like WBTC require a central custodian to hold the underlying BTC and issue a tokenized version on another chain. Roughly 72 percent of WBTC locked in DeFi is sitting in lending protocols, which confirms strong demand for using Bitcoin as collateral. But the custodian model concentrates trust. Hashi replaces the custodian with validator-level cryptographic consensus, which changes the risk profile significantly for institutional users and potentially for individuals as well.

The testnet launches with more than 25 confirmed participants, part of a broader coalition of more than 30 partners across custody, trading, DeFi, security, and wealth management. BitGo, Ledger, and Fordefi are handling custody infrastructure. FalconX, Bullish, Cumberland, and Erebor Bank are covering liquidity and trading. DeFi protocols on Sui including Suilend, Navi, Scallop, and AlphaLend are participating. Security firms Certora and OtterSec are among those handling audits.

Wave Digital Assets, an SEC-registered investment advisory firm, is named as a day-one institutional partner and plans to issue secured, rated bonds collateralized by Bitcoin using the Hashi system. Paul Kremsky, Global Head of Business Development at Cumberland, framed the opportunity plainly: "Bitcoin is the world's most liquid digital asset, but without native utility, it remains off-chain."

For developers in South Asia and Sub-Saharan Africa, the testnet opening represents a direct on-ramp that the broader protocol design does not yet fully address. India ranks first globally in crypto adoption according to the 2026 Global Crypto Adoption Index. Nigeria ranks second. Pakistan ranks eighth. Sub-Saharan Africa now has four countries in the global top 20, including Ethiopia, Kenya, and Ghana alongside Nigeria, up from two such countries in 2024.

Sub-Saharan Africa recorded stablecoin growth of more than 180 percent year-over-year, driven by remittances, merchant payments, and people protecting savings against local currency depreciation.

In those contexts, a system that lets a Bitcoin holder borrow stablecoins without selling their BTC functions as something close to a credit facility for populations without access to traditional lending. Approval barriers in conventional banking across these regions remain high. Bitcoin lending platforms currently offer faster processing with fewer documentation requirements, and Hashi's non-custodial architecture reduces the custodial risks that centralized alternatives carry.

None of the named launch partners are custodians or lending platforms with established operations in India, Nigeria, or Kenya. Regulatory frameworks for crypto lending remain unsettled in all three countries. India's central bank has maintained a cautious posture toward crypto credit products. Nigeria's SEC licensing process is still evolving. Kenya's capital markets regulator is running a sandbox program. Institutional product launches in these markets will require regulatory clarity that does not yet exist. Sui's own DeFi ecosystem has also contracted sharply, from a peak TVL of roughly $2.6 billion in October 2025 to approximately $570 million in July 2026, tracking the broader pullback from alternative layer-one networks. Rebuilding that liquidity base will be necessary before a robust Bitcoin-backed lending market can function on the network at scale.

Sui has processed 4.5 billion cumulative transactions as of July 21, with roughly 1.2 million daily active wallets. Mainnet is scheduled for later in 2026. The testnet phase will determine whether the protocol's security assumptions hold under real builder stress before those numbers are asked to support a live Bitcoin collateral market.