Fireblocks and 30+ founding members launched the Open Transaction Layer (OTL) on May 28, 2026 — an open-source protocol stack designed to standardize identity, messaging, compliance, and settlement coordination across onchain finance. The initiative brings together retail brokerages (Robinhood, e...
"Regulated institutions have to build bespoke connections to orchestrate their digital asset operations end-to-end. The result is integration sprawl and parallel systems that don't reconcile." — Idan Ofrat, Co-Founder and Chief Product Officer, Fireblocks
Fireblocks and 30+ founding members launched the Open Transaction Layer (OTL) on May 28, 2026 — an open-source protocol stack designed to standardize identity, messaging, compliance, and settlement coordination across onchain finance. The initiative brings together retail brokerages (Robinhood, eToro), payment processors (Checkout.com, MoonPay), banking infrastructure (Cross River Bank, SoFi), market makers (Wintermute, B2C2, FalconX), wallet providers (MetaMask, WalletConnect, Zengo), and six blockchain foundations (Solana, Stellar, Polygon, TON, Sui, Monad).
OTL addresses a structural problem: as institutions entered onchain finance, each built proprietary coordination layers for counterparty discovery, compliance verification, and settlement orchestration. The result is duplicated infrastructure across dozens of firms, each maintaining incompatible bilateral integrations. OTL proposes a shared, open standard that sits above chain-specific protocols and below application logic — comparable to what TCP/IP accomplished for networking but applied to financial transaction coordination.
The specifications are publicly available under an open-source license at otl.network. Reference implementations are expected to follow. Notably absent from the founding alliance are major exchanges (Coinbase, Binance, Kraken) and leading stablecoin issuers (Circle, Tether).
Institutional adoption of onchain finance accelerated through 2025-2026: Fireblocks alone reached an $8 billion valuation after its $550 million Series E, serving hundreds of institutional clients. DTCC deployed blockchain-based infrastructure under $114 trillion in custody. Paxos received SEC registration as the first blockchain clearing agency. Stablecoins crossed $323 billion in market capitalization.
Yet each institution entering this space built its own coordination stack. A regulated exchange needing to transact with a non-custodial wallet must independently solve:
According to Fireblocks, this produces "integration sprawl and parallel systems that don't reconcile." Each bilateral integration is custom-built. When Robinhood needs to settle with MetaMask users, that coordination logic differs entirely from how Robinhood settles with eToro or SoFi. Multiply this across 30+ counterparties and six blockchain networks, and the infrastructure cost becomes material.
The parallel in traditional finance is instructive. Before SWIFT standardized messaging in 1973, banks maintained separate telex procedures with each correspondent. Before ISO 20022, payment messages lacked structured data. OTL positions itself as the equivalent standardization layer for onchain finance — though it remains to be seen whether the industry coalesces around it or competing approaches emerge.
OTL organizes its protocol stack into five layers:
Layer 1 — Identity The foundation layer. Every subsequent function depends on verifiable counterparty identification. OTL uses W3C Decentralized Identifiers (DIDs) to establish cryptographically verifiable identities without relying on a central registry. This allows institutions, wallets, and autonomous agents to authenticate each other across chains and jurisdictions.
Layer 2 — Session Manages authenticated connections between parties. Once identities are established, sessions create persistent, encrypted communication channels for the duration of a transaction lifecycle. Sessions can span multiple messages and transactions.
Layer 3 — Transport Handles secure message delivery between participants. The transport layer is designed to be agnostic — messages can traverse different networks and infrastructure without requiring all participants to use the same underlying communication system.
Layer 4 — Messaging Defines structured data formats for transaction coordination. OTL incorporates IVMS101 (InterVASP Messaging Standard) for compliance data and ISO 20022 for payment information. CAIP-19 (Chain Agnostic Improvement Proposal) provides cross-chain asset identification.
Layer 5 — Applications The business logic layer where specific use cases are implemented. Applications compose elements from the four layers below to solve coordination problems. Two reference applications ship with the initial specification.
The decision to incorporate existing standards rather than invent new ones reduces migration friction. Institutions already implementing IVMS101 for Travel Rule compliance or ISO 20022 for payment messaging can extend those implementations into OTL rather than replacing them.
The founding alliance spans five categories, representing approximately $50+ billion in combined enterprise value:
Retail Brokerages & Exchanges: Robinhood, eToro
Payment & Commerce Infrastructure: Checkout.com, MoonPay, Cross River Bank, Taptap Send, Tazapay, Triple-A, Xendit, Coins.ph
Market Makers & Trading Firms: Wintermute, B2C2, FalconX, Zerocap
Wallet & Identity Providers: MetaMask, WalletConnect, Zengo, Privy + Bridge (Stripe-owned)
Tokenization & Compliance: Securitize, zerohash, SoFi, Orbital
Blockchain Foundations (via Blockchain Payments Consortium): Solana Foundation, Stellar Development Foundation, Polygon, TON Foundation, Monad Foundation, Sui Foundation, Mysten Labs
The composition reveals OTL's strategy: assemble the counterparties that actually need to coordinate with each other. When Robinhood sends funds to a MetaMask wallet, both are founding members. When Wintermute settles with Cross River Bank, both are present. When SoFi's stablecoin (launched on Solana in May 2026) transacts with Checkout.com's payment infrastructure, the coordination standard already covers both parties.
The notable absences — Coinbase, Binance, Kraken, Circle, and Tether — suggest either competitive positioning (Coinbase operates its own L2 Base with separate infrastructure ambitions) or that negotiations continue. The absence of Circle, which operates the second-largest stablecoin (USDC at ~$60 billion), leaves a significant gap in the payments coordination picture.
OTL ships two reference applications demonstrating how the five-layer stack solves real coordination problems.
Universal Deposit
Universal Deposit standardizes authenticated payment coordination between any counterparty pair — custodial or non-custodial, institutional or retail, human or AI agent. The protocol ensures that before funds move onchain, both parties have:
This pre-transaction coordination eliminates the current pattern where funds are sent to an address with no pre-verification, followed by manual reconciliation when something goes wrong.
Wallet Attribution
Wallet Attribution provides a decentralized mechanism to verify which entity controls a given blockchain address. Today, each institution maintains its own attribution database — compiling address-to-entity mappings through KYC processes, blockchain analytics, and third-party data providers. These databases don't interoperate.
OTL's Wallet Attribution creates a shared verification protocol where an institution can query whether an address is controlled by a compliant entity without revealing the identity to unauthorized parties. This directly supports Travel Rule compliance, which requires knowing the beneficiary's identity before processing transactions above threshold amounts.
OTL's timing coincides with accelerating Travel Rule enforcement globally. According to FATF data:
The "Sunrise Issue" — when a compliant VASP transacts with a counterparty in a non-compliant jurisdiction — remains the primary implementation challenge. OTL's cross-jurisdictional design directly addresses this by establishing a shared identity and compliance layer that functions regardless of whether both counterparties' home jurisdictions have implemented the rule.
For institutions, the economic calculation is straightforward: build proprietary Travel Rule compliance for each counterparty relationship (estimated at hundreds of thousands of dollars per bilateral integration), or adopt a shared standard that reduces the problem to a single implementation. The GENIUS Act's 48-day countdown to stablecoin regulation in the U.S. adds urgency — institutions need compliance infrastructure before rules take effect.
OTL enters a market with existing, partial solutions:
IVMS101: The InterVASP Messaging Standard covers Travel Rule data exchange between VASPs but does not address identity establishment, session management, or pre-transaction coordination.
SWIFT/ISO 20022: The dominant standard for traditional payment messaging, now adopted by 97% of global payments. OTL incorporates ISO 20022 rather than competing with it, suggesting complementary positioning. However, SWIFT has conducted its own blockchain interoperability trials with UBS, Citi, HSBC, and Chainlink.
W3C DIDs: Provide decentralized identity infrastructure but don't define how financial institutions should use them for transaction coordination.
Notabene, Chainalysis, Elliptic: Commercial solutions for Travel Rule compliance and blockchain analytics. These firms are not founding members, suggesting potential competitive tension with OTL's open-source approach to similar problems.
OTL's differentiation is scope: it attempts to combine identity, compliance, messaging, and coordination into a single integrated stack. Whether this breadth is an advantage (one standard to rule them all) or a liability (too ambitious to achieve adoption) depends on implementation execution and industry coordination.
For Fireblocks: OTL positions Fireblocks as the de facto infrastructure standard-setter for institutional onchain finance. As the initiative's founder and the firm whose $8 billion platform already serves as custody and transfer infrastructure for hundreds of institutions, successful OTL adoption cements Fireblocks' network effects. This follows the playbook of companies that commoditize complements — by open-sourcing the coordination layer, Fireblocks makes its own custody and wallet management platform more valuable.
For Blockchain Foundations: Six foundations joining signals that L1 protocols recognize coordination infrastructure as a prerequisite for institutional adoption. Solana, Stellar, and Polygon have each invested in payments use cases. A shared coordination standard above the chain layer reduces fragmentation and potentially increases total addressable market for all participating chains.
For eToro: The company's stock rose 5.32% on the announcement date, according to TradersUnion, reflecting market interpretation that OTL participation strengthens eToro's institutional positioning as the firm recently IPO'd on NASDAQ.
For the Absent Parties: Coinbase's absence is most notable. Its Base L2 network launched its own MCP Agent Gateway on May 26 — two days before OTL's announcement — with its own approach to AI-agent-to-DeFi coordination. Whether these initiatives eventually converge or compete remains unclear.
OTL represents the first serious attempt at an industry-wide coordination standard for onchain finance — one that bridges custodial and non-custodial wallets, centralized and decentralized finance, and human and AI-agent participants under a single protocol stack. The founding alliance's breadth suggests genuine industry demand for the standard.
The critical question is execution. Standards succeed through adoption, not announcement. SWIFT took years to reach critical mass. ISO 20022 migration began in 2004 and reached 97% adoption only in 2025. OTL faces the additional challenge of an open, permissionless ecosystem where participants can fork, modify, or ignore standards without contractual penalty.
The absence of major exchanges and stablecoin issuers is a gap, not a fatal flaw — SWIFT launched with 239 banks and grew to 11,000+. If OTL's reference implementations prove functional and the founding members actually adopt them in production, network effects may compel the absent parties to join.
For the onchain finance ecosystem, the economic question is whether coordination costs remain high enough to justify standardization. With Travel Rule enforcement accelerating across 85 jurisdictions, stablecoin regulation imminent in the U.S., and institutional transaction volumes growing, the economic case for shared infrastructure appears strong. Whether OTL captures that demand or merely demonstrates it exists will become clear over the next 12-18 months.