Sponge

What is Sponge?

Sponge is a financial infrastructure platform built for the AI agent economy and lets AI agents to autonomously hold, spend, invest, and earn both fiat currency and cryptocurrency without human intervention. It offers two core products: Sponge Wallet, which gives agents their own accounts for payments, transfers, and investments, and Sponge Gateway, which lets businesses accept direct payments from agents by uploading an API spec. Sponge is backed by Y Combinator (Winter 2026 batch) and was built by a team of ex-Stripe engineers based in San Francisco. It targets developers building agent-powered applications and businesses that want to sell services directly to AI agents.

Key Features

• Sponge Wallet: Gives AI agents dedicated accounts to deposit funds, make payments, execute transfers, and invest in fiat and crypto, all without requiring a human to authorize each action.
• Sponge Gateway: Lets businesses upload an API spec (such as OpenAPI) to automate agent onboarding and payment acceptance, removing the need for human-held credit cards or manual API key entry.
• Multi-Currency and Multi-Chain Support: Handles fiat alongside cryptocurrencies, including EVM and Solana transfers, on-chain swaps on Base and Solana, deBridge bridging, and SPL token support.
• Spending Controls: Developers can configure per-agent budget limits, such as a daily spending cap or per-transaction maximum, and restrict spending to approved domains.
• TypeScript SDK: A developer SDK for integrating Sponge wallets, payments, and controls into any agent stack.
• Audit Logs: Tracks all transactions for review with a record of agent spending activity.

Use Cases

• AI agent developers: Developers integrate Sponge Wallet into their agent stacks to give agents autonomous purchasing power, such as paying for web scraping APIs or external data services, without manual approval at each step.
• Businesses selling to agents: Service providers connect Sponge Gateway by uploading their API spec to accept payments directly from agents, replacing manual onboarding and billing processes.
• Autonomous investment and data workflows: An agent can purchase a financial report (such as a 10-K filing) via a paid API and then execute a stock trade if specific conditions are met, all within a single autonomous workflow.
• Agent-to-human or agent-to-agent payments: Agents can send money to vendors or other agents for completed work, such as transferring $150 for a design deliverable, with the transaction logged automatically.
• Budget-controlled deployments: Finance and operations teams configure spending limits per agent to keep costs predictable when running agents at scale.

Strengths and Weaknesses

Strengths:

• Ease of use is frequently cited, with an intuitive design and low-friction onboarding.
• Multi-chain crypto support reduces blockchain dependency for agent payment workflows.
• Designed specifically for machine-to-machine transactions, which most existing payment platforms do not natively support.

Weaknesses:

• Pricing is not publicly disclosed on the website, requiring direct contact with the team to evaluate costs.
• The platform is newly released and in beta, meaning features and availability may change.
• Published information on integrations and supported platforms is limited and is difficult to assess compatibility before signing up.

Pricing

Sponge's pricing is not publicly listed on paysponge.com. Interested developers and businesses should contact the Sponge team directly for pricing details. The platform is currently in beta.

FAQ

What is Sponge (paysponge.com)?

Sponge is a financial infrastructure platform that allows AI agents to autonomously hold and spend money using fiat currency and cryptocurrency. It provides wallets for agents and a payment gateway for businesses selling services to agents.

Who built Sponge?

Sponge was founded by ex-Stripe engineers and is part of the Y Combinator Winter 2026 batch, based in San Francisco.

What is Sponge Wallet?

Sponge Wallet is an account system for AI agents so them to store funds, make payments, send transfers, and execute investments in fiat and crypto without human involvement.

What is Sponge Gateway?

Sponge Gateway is a tool for businesses that want to sell directly to AI agents. By uploading an API spec, providers can automate agent onboarding and accept payments without requiring human credit cards or manual API key setup.

What blockchains does Sponge support?

Sponge supports EVM-compatible chains, Solana, and Base. It also supports on-chain swaps, deBridge bridging, and SPL tokens.

What developer tools does Sponge offer?

Sponge provides a TypeScript SDK that developers can use to integrate wallets, payments, and spending controls into their agent applications. A RESTful API with endpoints for transfers, swaps, and bridging is also available.

What integrations does Sponge support?

Sponge integrates with Claude, Steel (browser automation), and Amazon (in beta). It also supports OpenAPI specs for the Gateway product.

Can Sponge agents make autonomous investment decisions?

Yes. An example use case is an agent purchasing a financial data report via a paid API and then executing a stock trade if specific revenue conditions are met, all without human approval.

How much does Sponge cost?

Sponge's pricing is not publicly disclosed. You would need to contact the team directly at paysponge.com for current pricing information.

Is Sponge free to use?

No free tier has been confirmed for paysponge.com. Pricing details are not publicly available.

Who is Sponge designed for?

Sponge is built for two main groups: developers building AI agent applications who need their agents to make payments autonomously, and businesses that want to accept payments directly from AI agents.

Is Sponge available now?

Sponge is currently in beta. The platform is live but may evolve as it is newly launched.

What are the alternatives to Sponge?

Sponge is a niche product targeting AI agent payments specifically. There are no widely documented direct competitors indexed for this exact use case at the time of writing, though general payment APIs like Stripe could be used with custom agent integrations.

Does Sponge support spending limits for agents?

Yes. Developers can configure daily budget caps, per-transaction limits, and domain allowlists to control how much and where an agent can spend.