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The BoltzPay SDK ships with a built-in directory of 25 verified paid API endpoints across two payment protocols (x402 and L402). All endpoints were confirmed live as of February 2026.
The directory is static and bundled with the SDK. Entries may become outdated as endpoints go online or offline. Use the discover command or sdk.discover() method to probe endpoints in real-time and get live pricing.

Directory entries

x402 (USDC on-chain)

Crypto Data

NameURLPriceDescription
Invy — Token Holdingshttps://invy.bot/api$0.05Token holdings lookup across Base, Ethereum, and Solana
x402-tools — Polymarket Trendinghttps://x402-tools.vercel.app/api/polymarket/trending$0.01Trending prediction markets from Polymarket
Einstein AI — Top Tokenshttps://emc2ai.io/x402/bitquery/top-tokens$0.55Top tokens by market cap via Bitquery
Einstein AI — Whale Intelhttps://emc2ai.io/x402/bitquery/whale-intel/raw$0.85Whale wallet intelligence and tracking
Silverback — DeFi Top Protocolshttps://silverback-x402.onrender.com/api/v1/top-protocols$0.01Top DeFi protocols by TVL with multichain data
x402scan — Top Merchantshttps://x402scan-j55w7ornb-merit-systems.vercel.app/api/data/merchants$0.01Top x402 merchants by transaction volume
OttoAI — Token Security Audithttps://x402.ottoai.services/token-security$0.01Token security scan — honeypot, rug pull, proxy detection
Zapper — Token Rankinghttps://public.zapper.xyz/x402/token-ranking$0.01Trending tokens ranked by swap activity and adoption velocity
Zapper — DeFi Balanceshttps://public.zapper.xyz/x402/defi-balances$0.01DeFi positions (LP, lending, yield) for wallet addresses
Zapper — Transaction Historyhttps://public.zapper.xyz/x402/transaction-history$0.01Transaction history with interpretations for wallet addresses

Utilities

NameURLPriceDescription
x402-tools — Concertshttps://x402-tools.vercel.app/api/concerts$0.01Event and concert discovery
Auor — Public Holidayshttps://api.auor.io/open-holidays/v1/public$0.01Public holiday calendar by country and year
SocioLogic — Cryptographic RNGhttps://rng.sociologic.ai/random/int$0.01Cryptographically secure random integer
Grapevine — IPFS Gatewayhttps://gateway.grapevine.fyi/x402/cid/bafkreib7s7xuwc57wri43lyauwjeyfx3zqyc4ue34td5o7ab6wxp7sbqhm$0.01IPFS content retrieval via x402 payment gateway

Research

NameURLPriceDescription
PubMed Trendshttps://pubmed.sekgen.xyz/api/v1/trends$0.01Academic publication trends from PubMed
Hugen Scout — Intelligence Reporthttps://scout.hugen.tokyo/scout/report$0.01Multi-source intelligence report from HN, GitHub, npm, PyPI

Dev Tools

NameURLPriceDescription
Creative-Tim — Shadcn Blockshttps://x402.creative-tim.com/shadcn-blocks/user-payment$0.01View Shadcn UI component source code after payment

Demo

NameURLPriceDescription
Nickel Joke (Testnet)https://nickeljoke.vercel.app/api/joke$0.005 (testnet)Joke API on Base Sepolia testnet — useful for E2E testing
Hello Worldhttps://hello-world-x402.vercel.app/hello$0.01Returns “Hello World” after payment — simplest x402 sanity test
BoostPass Pinghttps://boostpass.qrbase.xyz/api/x402/ping$0.01Simple ping with payment confirmation and sender address
SkillfulAI — Demo Premiumhttps://api-dev.agents.skillfulai.io/api/x402/demo/mainnet/premium$0.01Demo premium endpoint with payment verification details

L402 (Bitcoin Lightning)

Crypto Data

NameURLPriceDescription
Satring — Analyticshttps://satring.com/api/v1/analytics100 satsBitcoin and Lightning network analytics (90 services, categories, pricing)
Satring — Service Reputationhttps://satring.com/api/v1/services/lightning-faucet-fortune/reputation100 satsDetailed reputation report for L402 services (replace slug in URL)

Categories

The directory organizes endpoints into 5 categories:
CategoryDescriptionx402L402Total
crypto-dataBlockchain data, token analytics, DeFi, whale tracking10212
utilitiesHolidays, RNG, IPFS, events404
demoTest and demo endpoints (often on testnet)404
researchAcademic and intelligence reports202
dev-toolsUI components and developer resources101

Programmatic access

API_DIRECTORY

The full directory as a readonly array of ApiDirectoryEntry objects.
import { API_DIRECTORY } from '@boltzpay/sdk';

for (const entry of API_DIRECTORY) {
  console.log(`${entry.name}: ${entry.url} (${entry.pricing})`);
}

ApiDirectoryEntry

interface ApiDirectoryEntry {
  readonly name: string;
  readonly url: string;
  readonly protocol: string;
  readonly category: string;
  readonly description: string;
  readonly pricing: string;
  readonly chain?: string;
  readonly status?: "live" | "testnet";
}

getDirectoryCategories()

Returns all distinct categories present in the directory.
import { getDirectoryCategories } from '@boltzpay/sdk';

const categories = getDirectoryCategories();
// ["crypto-data", "utilities", "demo", "research", "dev-tools"]

filterDirectory(category?)

Filter the directory by category. Returns the full directory if no category is provided.
import { filterDirectory } from '@boltzpay/sdk';

const cryptoApis = filterDirectory('crypto-data');
// Returns 12 entries in the crypto-data category

const all = filterDirectory();
// Returns all 25 entries

Live discovery

The static directory gives you a starting point, but endpoints can go offline. Use discover for real-time probing.

SDK

const entries = await sdk.discover({ category: 'crypto-data' });

for (const entry of entries) {
  if (entry.live.status === 'live') {
    console.log(`${entry.name}: ${entry.live.livePrice} (${entry.live.protocol})`);
  }
}
Results are sorted by status: live first, then offline, error, and free.

CLI

# Discover all endpoints
boltzpay discover

# Filter by category
boltzpay discover -c crypto-data

# JSON output for scripting
boltzpay --json discover -c utilities

MCP

AI agents can call the boltzpay_discover tool:
Use boltzpay_discover with category "crypto-data" to find blockchain data APIs.

Probe timeout

Each endpoint probe has a 5-second timeout (DISCOVER_PROBE_TIMEOUT_MS = 5000). Endpoints that do not respond within 5 seconds are marked as offline with reason "Timeout". You can pass an AbortSignal to cancel all probes early:
const controller = new AbortController();
setTimeout(() => controller.abort(), 10_000); // 10s total budget

const entries = await sdk.discover({
  category: 'crypto-data',
  signal: controller.signal,
});