A guide for finding paid online APIs and paying to use them through 402 Index. An API is a service that accepts a request from software and returns a result; the listed payment methods include Lightning, stablecoins, and machine payments.

Searching the 402 Index, comparing available paid APIs, handling HTTP 402 payment requests, paying through a supported method, and consuming the result.

It helps an agent obtain capabilities it does not already have, including services that charge per request.

402index — Skill for Claude Code and Codex by ryanthegentry

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent

npx skills add ryanthegentry/402index --skill 402index

Clone the repo

git clone --depth 1 https://github.com/ryanthegentry/402index

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/ryanthegentry/402index/402index/github.svg)](https://agentmods.dev/skills/ryanthegentry/402index/402index)

Your own site

<a href="https://agentmods.dev/skills/ryanthegentry/402index/402index"><img src="https://agentmods.dev/badge/skills/ryanthegentry/402index/402index/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/ryanthegentry/402index/402index"><img src="https://agentmods.dev/badge/skills/ryanthegentry/402index/402index.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 98 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 5,367 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00098	$0.05367
Opus 5.5	$0.00039	$0.02147
Sonnet 5.5	$0.00020	$0.01073
Haiku 4.5	$0.00010	$0.00537

Measured 2mo ago against content hash 140da9a7534c, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

402index scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2mo ago.

The scan reads SKILL.md. This mod also ships 18 executable files (scripts/backfill-embeddings.mjs, scripts/backfill-snapshots.mjs, scripts/backfill-unprobeable.mjs, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl -s "https://402index.io/api/v1/services?q=image+generation&health=healthy&protocol=MPP&sort=price&limit=5" | jq '.services[] | {name, url, protocol, price_usd, health_status}'

SKILL.md · 416 lines

How it starts

The opening of the file, as written. The whole thing — 416 lines — stays where its author put it; the contents beside it link to each section on GitHub.

402 Index — Discover and Pay for APIs

402 Index is a protocol-agnostic directory of thousands of paid API endpoints across three payment protocols: L402 (Lightning Network), x402 (Coinbase/EVM stablecoins), and MPP (Stripe/Tempo machine payments). This skill teaches you to discover APIs you need, select a payment method, and execute the payment — no API keys, no signups, just pay-per-request.

Live directory: https://402index.io API docs: https://402index.io/api-docs OpenAPI spec: https://402index.io/api/v1/openapi.json

When to Use This Skill

Use this skill when:

You need a capability you don't have (image generation, specialized models, real-time data)
The user asks you to find or use a paid API
You encounter an HTTP 402 Payment Required response
The user mentions 402index, L402, x402, MPP, or Lightning payments

Agent Behavior Notes

Run payment commands synchronously. Do NOT background lnget or mppx calls. Image generation takes 60-90s — wait for the result inline.
--no-pay only works for L402 endpoints, NOT for MPP. To preview MPP costs, check the price in the 402index listing before paying. Do not use --no-pay with --prefer-scheme payment.
If search returns errors, skip to the known-good endpoints below. Do not retry with different query variations — use the Quick Start or category-based search instead.

Quick Start

1. Discover  →  Search 402 Index for what you need (MCP or REST)
2. Evaluate  →  Check health, price, protocol
3. Detect    →  What payment tools are installed?
4. Pay       →  Execute payment with the right tool
5. Consume   →  Parse and use the response

Known-good endpoints (fallback)

If search_services returns errors, use one of these verified endpoints instead. Last verified: 2026-04-24. For current status, check each listing on 402index.io.

Table order: one endpoint per protocol, plus one dual-rail example (llm402 Kimi-K2.6) showing an endpoint that accepts both L402 and x402 payments against the same URL — a pattern 402 Index tracks natively.

Read the full file on GitHub · 416 lines

Files

What ships with it

18 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

2mo ago First seen · 416 lines · 98 tokens per session scan A 140da9a7534c

Subscribe to this mod's changes

402index is a skill published in the GitHub repository ryanthegentry/402index (1 stars, last pushed 6d ago), licensed MIT. It adds 98 tokens to every session and 5,367 once invoked, about $0.0004 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

Building agents Finance and fintech

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402index