CMT Digital and Lightspeed Faction co-led the round, announced September 3, 2026. The raise is more than five times the roughly $1.82 million the company had raised across all prior equity rounds through 2019, and follows a $2.9 million European Union research and development grant the firm received in 2022.

Diameter Pay is not a consumer product. It sells application programming interfaces (APIs) to banks and regulated financial institutions, allowing them to offer clients cross-border transfers that settle either through conventional correspondent banking channels or, increasingly, through on-chain stablecoin corridors. The company says it has processed over $10 billion in payments to date. The new capital is specifically earmarked to expand the stablecoin settlement side of that business.

The company has a longer history than its current identity suggests. It started out in 2017 as SendFriend, a consumer remittance app built at MIT, with early support from Techstars and the Barclays Accelerator. After pivoting toward business-to-business infrastructure and acquiring regtech solutions provider DigiPli, it rebranded as Diameter Pay in April 2023.

David Lighton, the company's founder and CEO, framed the mission plainly at the time of the rebrand: "Diameter Pay is a response to today's global marketplace, which desperately needs safe international fund transfers but often fails emerging, fast-growing regions for arbitrary risk or geopolitical reasons."

The compliance layer matters as much as the technology. In July 2025, Diameter Pay partnered with AML monitoring firm Flagright to add real-time transaction screening, automated risk scoring, fraud detection, case management, and regulatory reporting to its APIs.

That is not a minor addition. East Africa and South Asia sit among the most heavily scrutinised jurisdictions for financial crime compliance, and correspondent banks have been known to pull back from those corridors rather than absorb the oversight cost. Diameter Pay's approach bakes that compliance infrastructure directly into its API product, lowering the burden on smaller financial institutions that lack in-house screening capacity.

The macro environment supports the bet. Stablecoin-settled real payments reached an estimated $400 billion in 2026, a roughly 733% increase year over year, according to OpenFX and Stablecoin Insider. The global stablecoin market cap now exceeds $300 billion. The growth is no longer primarily speculative or concentrated in decentralised finance; an increasing share is business-to-business cross-border settlement. The IMF has described stablecoins as having "transformed from niche technology into a meaningful cross-border payments channel, enabling rapid transactions for unbanked populations with internet access," according to PYMNTS reporting in 2026.

The regional stakes are high. In Sub-Saharan Africa, stablecoins now account for roughly 43% of all crypto transaction volume, according to the Milken Institute. Nigeria alone has absorbed approximately 60% of sub-Saharan Africa's total stablecoin inflows since 2019. A 2026 survey found 95% of Nigerian respondents prefer to receive payments in stablecoins over naira, yet 42% of middle-market Nigerian companies have only discussed stablecoins without acting, and just 13% have moved to actual usage, leaving substantial room for infrastructure providers.

Sending $200 through conventional channels to sub-Saharan Africa costs around 9% in fees on average; stablecoin corridors reduce that cost materially, though precise savings vary by corridor and provider.

In South Asia, India recorded an estimated $89 billion in stablecoin volume from domestic addresses in 2024 alone, and the broader region posted an 80% increase in stablecoin-driven payment volumes through mid-2025, per cross-border payments platform Tazapay. Regulatory friction is real and should not be underplayed. India's Reserve Bank has actively restricted private stablecoin products while advancing its own digital rupee pilot.

Across Africa, exchange control laws in Nigeria, South Africa, Kenya, and Ethiopia represent the primary structural barrier to scaling stablecoin payment volumes, and those laws predate crypto by decades. Diameter Pay's bank-facing model may offer a more durable path through these constraints than consumer apps have managed, but it is still threading a narrow needle.

The investors bring relevant connections. CMT Digital, a Chicago-based crypto venture firm with a portfolio spanning over 150 blockchain businesses, protocols, and tokens, is an existing backer of Circle, the issuer of USDC, currently the second-largest stablecoin by market capitalisation. That relationship could prove useful if Diameter Pay leans into USDC liquidity for its settlement corridors, particularly in markets like Nigeria and Kenya where USDC has established trading depth.

Lightspeed Faction, the blockchain-focused fund launched jointly by Lightspeed Venture Partners and Faction, closed its debut $285 million fund in July 2023, surpassing an original target of $250 million, with a portfolio that includes Crossmint, Lens Protocol, Matter Labs (zkSync), Narya.ai, and Skip.money.

For banks and fintechs in Emerging Asia and Africa watching this space, the practical implication is this: Diameter Pay is not asking institutions to rebuild their payments stack. It is offering a licensed, compliance-equipped API layer that adds stablecoin settlement as one more option alongside existing wire and correspondent banking flows. Whether that quiet approach reaches meaningful scale depends largely on how quickly regulators in its target markets create room for institutions to use it.