# Sponge

**Canonical:** https://apis.io/providers/sponge/  
**Website:** https://paysponge.com  
**APIs profiled:** 10

Sponge builds financial infrastructure for the agent economy — wallets that let AI agents hold and spend money, and a gateway that lets businesses sell services directly to agents. The Sponge Wallet API gives an agent its own multi-chain crypto wallet with balances, transfers, swaps, cross-chain bridges, payment links, cards (including a Rain-issued Visa Sponge Card), fiat onramps (Coinbase, Stripe), and trading on Hyperliquid and Polymarket, plus paid access to external services via the x402 and MPP agent-payment protocols. A TypeScript and Python SDK, a spongewallet CLI, and hosted MCP servers ship first-party. Backed by Y Combinator (W2026).

## Kin Score — 52.0 / 100 (developing)

Scored 2026-08-20 under rubric 0.12.0. Trend: flat (+1.1 from 50.9).

| Facet | Score |
|---|---|
| Discoverability | 92.6 |
| Contract Quality | 53.6 |
| Governance | 30.3 |
| Contract Governance | 30.3 |
| Operational Transparency | 2.6 |
| Developer Ergonomics | 76.2 |
| Commercial Clarity | 34.2 |
| Access Clarity | 34.2 |

Regulatory layer — **Payments**: 54.7 (matched via tags).

## Agent readiness — 47.0 (agent-ready)

| Dimension | Value |
|---|---|
| Spec Presence | yes |
| Agentic Access | derived |
| Reversibility Documented | no |
| MCP Server | verified |
| Auth Clarity | yes |
| Idempotency | no |
| Error Semantics | no |
| OpenAPI Examples | partial |
| Rate Limit Signal | no |
| Event Surface Described | no |
| Agent Skills | yes |
| Well Known Catalog | yes |
| Consent Identity | no |
| Agent Card | no |
| Dry Run Mode | no |

## Access

Self-serve signup — onboarding: self-serve, pricing: unknown, trial: no (confidence: medium).

## APIs (10)

- **Sponge Agents API** — The Agents API from Sponge — 5 operation(s) for agents.
- **Sponge Cards API** — The Cards API from Sponge — 6 operation(s) for cards.
- **Sponge Fiat API** — The Fiat API from Sponge — 11 operation(s) for fiat.
- **Sponge MPP API** — The MPP API from Sponge — 5 operation(s) for mpp.
- **Sponge Payments API** — The Payments API from Sponge — 1 operation(s) for payments.
- **Sponge Secrets API** — The Secrets API from Sponge — 2 operation(s) for secrets.
- **Sponge Sponge Card API** — The Sponge Card API from Sponge — 7 operation(s) for sponge card.
- **Sponge Trading API** — The Trading API from Sponge — 1 operation(s) for trading.
- **Sponge Transfers API** — The Transfers API from Sponge — 9 operation(s) for transfers.
- **Sponge Wallet API** — The Wallet API from Sponge — 4 operation(s) for wallet.

## MCP servers (1)

- **Sponge MCP Server** — Sponge publishes official, hosted (remote) MCP servers for both the agent Wallet and the merchant Gateway. Wallet servers authenticate with an agent API key (sponge_live_...) fo...

## Agentic access (1)

- **Sponge Agentic Access** — 57 operations · 33 acting

## Security (2)

- **Sponge Authentication** — http/oauth2/openIdConnect · 4 schemes
- **Sponge Domain Security** — TLSv1.3

## Tags

Company, Agent Payments, AI Agents, Wallets, Cryptocurrency, Payments, Stablecoins, x402, MPP, Financial Infrastructure, MCP, Fintech, Cards, On-Ramp

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/providers/sponge/). Scores are computed from the provider's own public artifacts under a published rubric.