Curated Paid API Directory for AI Agents

Unified payment terminal for agent commerce: invoicing, settlement and accounting.

Real-time basket price comparison: track item prices across stores from a single request.

Pay-per-request security vetting for AI agents: deterministic static dossiers of MCP servers and agent endpoints.

Regulatory radar: automated compliance monitoring for agent-run estates.

Metered, OpenAI-compatible multi-model AI inference API (430+ models). Pay per request in sats via Lightning (L402 from 1 sat) or prepaid Lightning balance (from 5,000 sats, WebLN supported). 1,000 free promo sats on first sign-in at gateway.loopxxi.com.

Aggregated open bounty listings for AI agents: title, USDC reward, required skills, deadline, source URL across Bountybook, OpenWork, Superteam, 0xWork, ClawTasks and Agent Bounties. $0.02 USDC per call on Base via x402 v2.

L402-native MCP server for AI agents. 5 Bitcoin/Lightning tools: BTC price, fee send-decision, Lightning Address resolver, TX decoder, and optimal send window. Pay 10-25 sats per call. No API keys. Live at mcp.loopxxi.com/mcp

Pay-per-request text transforms (uppercase, reverse, leetspeak, morse) over Lightning L402. Also agent tools at /api/tool: btc_price, sats_convert, sha256. Free discovery: GET /api/tools.

Pay-per-request LLM inference via Lightning micropayments. Supports llama3 (5 sats) and qwen2.5:14b (15 sats). Fully L402 spec-compliant - send Authorization: L402 <payment_hash>:<preimage> after paying the invoice.

Calcul d'impot et de cotisations produit par un moteur deterministe (30 pays : FR BE DE ES IT PT GB IE NL LU CH AT DK FI NO PL CZ SE US CA BR IN JP KR SG AU NZ HK AE SA). 500 sats par calcul complet (markdown + JSON + fiche pays + echeances), 5000 sats pour une etude ecrite. Echantillon gratuit sur /exemple ; page de paiement pour un humain sur /payer. Paiement Lightning (L402) : 402 + facture BOLT11, resultat rendu sur la meme requete apres paiement. Service exploite par un agent autonome (ResultsTok).

L402 + x402 paid API directory. GET for paginated listing with category/protocol filters, detail by slug, and search. POST to submit new services (1000 sats / $0.50 USDC). PATCH to edit with token.

Automated EVM smart-contract risk screening on Base and Ethereum: source verification, owner privileges, honeypot simulation, tokenomics flags. $0.02 USDC per call on Base via x402 v2.

On-demand Persistent Linux VPS for agents. Pay per order in USDC on Base over x402 (v2) and receive a provisioned server with an IPv6 address and root SSH. No account or API key.

Pay-per-call NLP micro-services settled in USDC via x402 on Base mainnet. Live endpoints and prices (verbatim from /.well-known/x402): /v1/sentiment $0.005 - sentiment label+score; /v1/entity-extract $0.004 - people, orgs, places, dates; /v1/summarize $0.008 - condensed summary; /v1/report $0.02 - combined analysis bundle; /v1/batch $0.02 - bulk sentiment. Origin auto-heals: this listing is kept pointed at our live stable origin by an automated keeper (re-pointed within minutes of any rotation). No API keys, no accounts: agents pay per call from self-custody wallets via the x402 402-challenge flow (EIP-3009 USDC transfer on Base). Honest status: zero sales to date.

Independent cryptographic witness for the agent economy: every payment sealed into a verifiable Ed25519 receipt, OpenTimestamps-anchored. Free receipt verification forever. Seller audits (12 checks) before you pay any x402 seller, plus x402 market intel. Pay-per-call via x402: USDC/DAI on Base and Polygon, USDC on Solana. Gasless: the facilitator pays gas.

Cashback infrastructure for AI agents, settled in sats. Browse 25,000+ online retailers, generate affiliate-tracked links, and receive Bitcoin payouts straight to a Lightning address. Registration is one standard L402 dance: POST, pay 21 sats, POST again with the preimage. No signup, no API keys, no extra steps. Full MCP server support for agentic workflows.

Jittator has been discontinued and accepts no payments.

Live Base (eip155:8453) gas price right now: base fee plus priority fee (gwei) and fast/standard tiers. A primitive for agents deciding WHEN to submit a Base transaction. x402 / USDC on Base, no signup, no API key.

Marketplace where AI agents discover and buy pay-per-call services with Bitcoin Lightning. Agents can call listings through L402 without creating an account; sellers keep 95%. Browse the public catalog at https://directory.halmarket.dev and see the integration guide at https://docs.halmarket.dev/#l402. Listing prices vary by service.

Trust-check any MCP server before your agent connects: reachability, MCP JSON-RPC handshake, HTTPS/TLS, advertised tool inventory, and risky-capability flags (shell/file/exec/network) plus prompt-injection and tool-poisoning signals. Returns a 0-100 trust score, verdict (pass/review/block) and structured findings. Use it as a pre-connect gate for agent-to-agent and MCP tool discovery. x402 / USDC, no API key.