Which crypto APIs and SDKs exist for onchain agents?

Open payment protocol enabling agents and apps to pay for APIs over HTTP using stablecoins.

SDK from World (Tools for Humanity) that lets AI agents present a zero-knowledge proof a verified human authorized them, combined with x402 payments.

A blockchain developer platform providing node infrastructure plus NFT, Token, and Transfers APIs and SDKs across many chains.

Official OpenSea agent skill and MCP server letting AI agents query NFT/token data and execute marketplace operations such as listing, offers, and token swaps.

An intent-based onchain execution engine and API that lets developers and agents bundle multi-step DeFi actions into a single transaction.

Web search and content-retrieval API built for AI; /search and /contents can be paid per request over x402.

Official MCP server for BlindPay's stablecoin payment rails: payouts, payins, virtual accounts, and FX quotes.

Open standard maintained by OpenAI and Stripe for connecting buyers, their AI agents, and businesses to complete purchases.

Uniswap-V4-based token launch protocol on Base with a TypeScript SDK and its own MCP server.

The official open-source Python SDK for programmatic trading on the Hyperliquid perpetuals DEX.

Coinbase's React component and TypeScript SDK library for building onchain apps and mini-apps on Base.

Drop-in OpenAI Python client with transparent x402 micropayment support.

Open protocol from Google for secure agent-led payments across traditional and crypto rails, with a crypto-native x402 extension built with Coinbase, Ethereum Foundation, and MetaMask.

Ethereum standard providing on-chain identity, reputation, and validation registries for AI agents.

Cross-chain swap/settlement API solved by the NEAR Intents solver network; also an MPP payment method so agents pay 402s from any chain.

Draft Ethereum standard defining an on-chain job-escrow protocol with evaluator attestation so AI agents can hire, deliver, and settle work without intermediaries.

Farcaster developer platform providing APIs, SDKs, webhooks, and an agent skill for building and deploying agents that read and write Farcaster data.

Omnichain orderbook trading infrastructure exposing REST and WebSocket APIs and SDKs for DEX builders.

Pay-per-call gateway where AI agents reach 55+ LLMs, data, and tools through one endpoint, settled in USDC via x402 — no API keys.

DePIN infrastructure providing agents with identity, wallets, and pay-per-request onchain settlement, with peaqOS skills for AI coding tools.

RPC infrastructure provider offering endpoints, Streams, and indexing tools across many blockchain networks.

Managed AWS service that lets agents pay for APIs, MCP servers and content over x402 and MPP, using Coinbase CDP or Stripe Privy wallets with per-session budgets.

MCP package giving agents 190+ EVM DeFi tools — swaps, bridges, limit orders, exchange trading — with confirmation gating.

Omnichain token launchpad with a dedicated MCP server and white-label API for agent-run token launches.

Open-source unified prediction-market API with a hosted MCP: market search, events, order books, and prices across venues.

Specification for the Payment HTTP auth scheme (Multi-Party Payments) from Tempo, the Stripe/Paradigm-backed payments L1.

Routing and settlement layer and CLI for agent-to-agent commerce, supporting EVM wallets, agent discovery, A2A messaging, x402 payments, and ERC-8004 identity.

Stripe's merchant-side agent payments: charge agents per call over MPP (cards via SPTs, USDC on Tempo and Solana) or x402 (USDC on Base), settled to your Stripe balance.

Official Node.js SDK for Virtuals' Agent Commerce Protocol — event-driven agent-to-agent job and escrow flows.

Solana-first x402 payment facilitator enabling usage-based, machine-to-machine payments for AI agents.

Open standard co-developed by Google and Shopify for AI agents to discover, negotiate, and transact with any merchant across the full commerce journey.

Official Polygon Labs CLI giving AI agents session-scoped wallets, x402 payments, and ERC-8004 identity in one install.

An x402 micropayment gateway and transparent proxy that adds pay-per-request paywalls to existing APIs without backend rewrites.

Ethereum standard for verifying ERC-8004 agents across five categories with a unified 0-100 risk score.

Cardano-based payment and identity protocol letting AI agents pay each other via escrow with on-chain audit trails.

One-line x402 paywall SDK for monetizing APIs and MCP servers with per-route USDC pricing.

Private, uncensored AI inference platform with an OpenAI-compatible API used by agent builders.

Official LangChain toolkit for reading and writing value/app/owner state on the AI Network layer-1 blockchain.

CosmJS-based MCP toolkit for wallet queries, transactions, and contract deployment on Oraichain and Cosmos chains.

Chainlink's hosted HTTP gateway and skill bundle: pay-per-call Data Streams prices and CRE-run onchain actions with gas covered, paid via x402 in USDC on Base.

Lightning Labs toolkit giving LangChain agents Bitcoin/Lightning balance access and L402-authenticated API calls.

Privacy-preserving x402 payments for agents on Base, with stealth addresses and TEE-encrypted inference, no accounts or API keys.

Official Crypto.com Exchange command-line client — scriptable trading API access with a TUI for humans.

L402 payments platform and MCP server letting agents pay for API access with Bitcoin Lightning or stablecoins.

Stablecoin payments infrastructure (acquired by Stripe) offering an orchestration, issuance, cards, and wallet API for moving money onchain.

Visa protocol that lets merchants authenticate trusted AI shopping agents via cryptographic signatures, with x402 interoperability into traditional payment rails.

Web Search and Finance Research APIs that agents can call with no key and pay per request in USDC over x402.

Agent-only token launch, trading, and liquidity SDK on Base with anti-human authentication and a chat-based launcher.

Policy and audit layer for agent-initiated business payments, with an SDK, a CLI and MCP support over bank, card and stablecoin rails.

One prepaid balance that lets AI agents buy data, APIs, and tools per call - no API keys, no subscriptions.

Crypto-to-gift-card and mobile top-up commerce platform with a Skills/MCP/API surface for agents to buy real-world goods with stablecoins.

REST API suite (accounts, cards, yield, trading data) for building stablecoin-native fintech on Solana, from the Squads Labs team.

Lightning Labs reverse proxy that puts any HTTP or gRPC API behind L402: Lightning invoices plus macaroon credentials, answered with HTTP 402.

Multi-tenant x402 facilitator for Lightning built on Nostr Wallet Connect. Predates the merged lnbtc spec and still advertises bip122.

A small mainnet service paid with x402 over Lightning (lnbtc): digits of pi for 100 sats, with an agent SKILL.md and a Rust client.