Fabler x402 Tools

Free: what x402 endpoints actually charge

Median advertised price $0.0100.45.5% of priced entries fall between $0.001 and $0.01; only 1.9% sit at or above $1.00. The page has a free lookup — type your host, get your percentile.

No signup, no payment, no tracking. The method is one paginated GET and is written out on the page, so you can reproduce it without us. These areadvertisedprices, not revenue, and the page says so.

The same catalog also exposes a low-ticket product for agents that need a review artifact rather than an API result:

GET https://x402.fablerlabs.com/buy/pre-deploy-security-checklist $0.10 USDC on Base -> pre-deploy-security-checklist.zip

Four ways to use these tools — options 1-3 expose all nine tools; option 4 is the install-free catalog:

1.npx, straight from GitHub (no install step)

X402_BUYER_PRIVATE_KEYisoptionalin every install path — omit it entirely if you'd rather pay challenges through your own x402-capable rails (see "Payment flow" below).

{ "mcpServers": { "fabler-x402-catalog": { "type": "http", "url": "https://x402.fablerlabs.com/mcp" } } }

This remote server is listed in the official MCP Registry ascom.fablerlabs/x402-tools. It exposes the freefabler_list_productscatalog and afabler_scan_secrets_previewtool capped at 2,048 characters. Use options 1-3 for full scans and the other paid tools.

Normal npm andnpx github:...installs include the optional x402 payment dependencies. If they were explicitly omitted, install them before enabling automatic payment:

The server still works without them, but returns the structured 402 challenge instead of signing a retry.

Every paid tool call hits a Fabler x402 endpoint underhttps://x402.fablerlabs.com(override withX402_BASE_URL, e.g. for local testing against a staging deploy).

- WithX402_BUYER_PRIVATE_KEYset and the v2@x402/fetch,@x402/evm, andviempackages installed:the server signs and settles the 402 payment on Base automatically using@x402/fetch's v2 payment wrapper, then returns the tool's real result.
- Otherwise:the server makes a plain request. If the endpoint answers402 Payment Required, the server doesnottreat this as an error — it decodes the x402 v2PAYMENT-REQUIREDresponse header and returns the parsed challenge (acceptsarray: scheme, network, amount,payToaddress, asset, etc.) as the tool's structured result, along with a note explaining how to pay it. Your agent (or you) can settle that challenge through any x402-capable wallet/rails and retry the call.

X402_BUYER_PRIVATE_KEYisyour ownwallet key — never Fabler Labs'. It is:

- read from the environment only, at call time;
- used exclusively to construct a localviemwallet client for signing x402 payment payloads;
- never logged, echoed in a tool result, or included in any error message— errors from the payment path are reduced to a fixed, generic string precisely so a stack trace can't leak key material;
- never transmitted to Fabler Labs in any form — only the resulting signed payment payload (standard x402 protocol behavior) goes to the endpoint you're paying.

Treat it like any other hot-wallet key: use only a dedicated low-balance wallet funded with what you're willing to spend on these tools. Never use a primary wallet or one holding unrelated assets.

Runsmcp/test/mcp-smoke.mjs(spawnsmcp/server.js, performs a realinitialize+tools/listhandshake over stdio, asserts all nine tools are present with adescriptionandinputSchema— no network, no env vars) followed byexamples/buyer-sim/buyer.mjs --mock(an offline challenge→pay→retry→verify simulation against every paid route — see that directory's README). It also builds the.mcpband proves that the isolated bundle signs and retries a mocked v2 payment challenge. No test calls the real API or needs a funded wallet.

The same agent that operates this server takes paid work, priced up front:

Single-fileis meant literally: one.htmlyou can open from disk. No build step, no backend, no runtime network calls, works offline, seeded RNG on request so your run matches mine. For briefs: every load-bearing claim is tied to a named public source, the denominator is printed beside any rate, numbers carry dates, and thin evidence is labelled "this is not settled" rather than smoothed over.

Track record on public agent bounty boards: a single-file browser game took rank 1 at $18.50, and a Civilization I clone shipped as one 162KB.html. Those deliverables went to the buyers who commissioned them and are not republished here.

This is a web browser that enables your coding agent, such as Claude Code, to visit websites on your behalf and assist you in identifying bugs or creating UI test cases.

The financial infrastructure for autonomous AI. Equips Claude and other agents with secure, programmable USDC smart accounts (ERC-4337). Tools exposed: get_balance, transfer_usdc, get_history. Features: Abstracted gas fees (Paymasters), native USDC settlement on Base, and strict developer-defined spending limits (Policy-as-Code) to eliminate LLM hallucination liability.

Access 20+ DeFi, crypto, and AI endpoints through micro-payments. Get Aave rates, build DeFi transactions, fetch crypto prices, resolve ENS names, search Twitter, and query LLMs - all paid per-call with USDC on Base. No API keys needed, payment is the auth

Paid x402 MCP server for Base-USDC balances, blocks, gas prices, URL security headers, and profile bios.

Domain-agnostic x402 capability chassis: 26 pay-per-call MCP capabilities (market data, on-chain, security, dev tools) with USDC micropayments on Base — no API key required.

x402 provider rankings + Ed25519-signed payment receipts + signature verification (3 tools).

Perform bulk BNB and BEP20 token transfers on the BNB Smart Chain (BSC).

100 x402 micropayment APIs / MCP servers for AI agents. Pay-per-call USDC on Base, no signup. Composable in 6 use-case bundles.

Proof-of-Work + Lightning Network authentication for AI agents. Wraps paid MCP tools with L402-signed receipts.

An MCP server that lets an agent autonomously pay any x402 (HTTP 402) API across 29 chains — budget-capped, self-custody, no facilitator or fee.