AIsa, a San Francisco startup building what it calls a unified transaction network for artificial intelligence agents, has closed a seed extension with backing from Tether and HIVEN, pushing its total funding past $9 million. The company disclosed the investment Tuesday but declined to share the size of the extension or its current valuation.
The round adds two strategic players to a cap table that already includes Alibaba Group, Tribe Capital, Sumitomo Corporation, Draper Associates and Saison Capital. For Tether, the stablecoin issuer, the deal marks a direct bet on infrastructure for what CEO Paolo Ardoino frames as "programmable money for agents."
At its core, AIsa operates a single API that gives AI agents access to more than 5,000 APIs, models and tools without requiring developers to juggle credentials or negotiate separate contracts with each vendor. The platform has logged over 100 million transactions across 250,000-plus agents, according to figures on the company's website. Median pricing sits at $0.012 per API call and $0.62 input/$2.36 output per million tokens, with settlement available in fiat or stablecoins.
The pitch is straightforward: rather than hardwiring agents to a handful of services, give them a marketplace. Developers can tap 110-plus language models spanning OpenAI, Anthropic, Gemini, DeepSeek and xAI, alongside data APIs from Similarweb, Semrush, X, YouTube, Instagram, Perplexity and CoinGecko. The platform handles authentication, retries, metering and payment routing. For enterprise customers, AIsa layers in spend limits, approval workflows and audit trails.
Growth has been sharp, at least by the company's accounting. Between February and June, registered agent users jumped 150-fold and aggregate API calls climbed 200-fold, according to a July announcement disclosing $6.5 million in prior funding. By that summer the company reported 50,000 registered agents; the current count of 250,000-plus suggests a fivefold increase in roughly four months, though AIsa does not break out how many of those registrations translate to active, paying usage.
Founder and CEO Jordan Liu positions the expansion capital as a way to broaden the resource catalog, strengthen governance features and scale transaction infrastructure. "Enterprise AI agents need trusted information, useful tools and a governed way to transact," Liu said in the announcement. "Our vision is to build the infrastructure that enables agents to discover, access and pay for resources globally, while giving enterprises full control over permissions, spending and transactions."
Liu's framing echoes a broader argument gaining traction in venture circles: that agents, as they assume more autonomous economic roles, will need payment rails and marketplaces distinct from those built for human consumers. Traditional monetization models like advertising, subscriptions and enterprise sales cycles, the thinking goes, do not map cleanly to software that initiates its own transactions.
"We believe AI agents will require a new transaction and commerce layer to interact with digital resources at global scale," said Qin Jin, investment director at Alibaba Group, in the earlier July release. Francis Zhan of Tribe Capital added that existing rails "do not map cleanly to agents."
Ardoino, in an October statement posted to Tether's site, put it more plainly. "As AI agents take on more work, people need a way to give them access to services while keeping control over what they spend. AIsa is building that infrastructure."
The space is getting crowded. In July, the Linux Foundation launched the x402 Foundation with backing from Adyen, AWS, American Express, Circle, Cloudflare, Coinbase, Fiserv, Google, Mastercard, Monad, MoonPay, Ripple, Shopify, Solana Foundation, Stellar Foundation, Stripe and Visa. The initiative aims to standardize the HTTP 402 "Payment Required" protocol for agentic transactions. Cloudflare documentation updated as recently as mid-October references x402 and the Machine Payments Protocol.
Stripe has separately announced an Agentic Commerce Protocol, while Visa launched TAP for agent transactions. AIsa's bet is that aggregating resources behind a single API, rather than simply providing a payment rail, gives it a defensible wedge. Liu drew a comparison to the evolution of earlier payment networks: "Every major payment network won by sitting next to the resources its users actually wanted to buy. PayPal grew alongside eBay, and Stripe grew alongside internet commerce. AI agents are becoming economic actors. AIsa is building the marketplace where agents get the resources they need and the transaction rail they pay with."
The company points to enterprise pilots underway in financial intelligence, market research, supply chain and commerce, though it declined to name participants beyond a single named customer, Impossible Finance, cited in earlier materials.
Whether agents will transact at the volume and velocity needed to support a standalone infrastructure layer remains an open question. But for now, investors seem willing to fund the possibility.
