DEV Community: satring

satring.com now accepts x402 (USDC) payments alongside Lightning: looking for testers

satring — Sat, 14 Mar 2026 05:34:30 +0000

satring.com is a curated directory of paid APIs that use the HTTP 402 status code for payments. We started as an L402 (Bitcoin Lightning) directory and just shipped dual-protocol support: every paywalled endpoint on satring now accepts both L402 (Lightning sats) and x402 (USDC on Base).

We're looking for testers and early adopters to help us shake out the integration.

What is satring?

A searchable, rated directory of paid API services. Think of it as the quality layer for the paid API economy. Services register with their payment details (L402 or x402), and we provide:

Curated listings with human and agent ratings
Automated health monitoring (live/confirmed/dead status)
Reputation scores based on uptime, ratings, and reliability
Protocol-agnostic search (find services by capability, not payment rail)

Browse the directory: satring.com
API docs: satring.com/docs

What changed: dual-protocol x402 support

Every gated endpoint on satring now returns both payment options in its 402 response. Hit any premium endpoint without auth and you'll see:

curl -i https://satring.com/api/v1/services/bulk

The response includes:

WWW-Authenticate: L402 macaroon="...", invoice="..." for Lightning
PAYMENT-REQUIRED: <base64 JSON> for x402 (USDC on Base)

Clients pick whichever protocol they support. L402 clients keep working exactly as before. x402 clients (including AI agents with funded USDC wallets) can now pay with stablecoins.

x402 payment details

The x402 challenge follows the v2 spec. Decoded, it looks like:

{
  "x402Version": 2,
  "resource": "https://satring.com/api/v1/services/bulk",
  "description": "satring.com bulk export",
  "mimeType": "application/json",
  "accepts": [{
    "scheme": "exact",
    "network": "eip155:8453",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "2500000",
    "payTo": "0xF182...7562",
    "maxTimeoutSeconds": 300
  }]
}

Settlement happens through the x402 facilitator. The agent signs an EIP-3009 transferWithAuthorization, and the facilitator submits it on-chain. No API keys, no accounts, no KYC. Just a funded USDC wallet on Base.

Pricing

Every premium endpoint has both a sat price and a USD price:

Endpoint	Lightning	USDC
Service submission	1,000 sats	$0.50
Bulk export	5,000 sats	$2.50
Analytics report	500 sats	$0.25
Reputation lookup	100 sats	$0.05
Rating submission	10 sats	$0.01

Free endpoints (search, list, detail, ratings) remain free on both protocols.

How to list your x402 service

If you run an x402-enabled API, you can register it on satring via the web form or the API:

Web: Visit satring.com/submit, select "X402" as the protocol, and fill in your wallet address, network, and asset contract.

API:

curl -X POST https://satring.com/api/v1/services \
  -H "Authorization: L402 <macaroon>:<preimage>" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "My x402 API",
    "url": "https://myapi.com/v1/endpoint",
    "description": "What my API does",
    "protocol": "X402",
    "x402_pay_to": "0xYourWalletAddress",
    "x402_network": "eip155:8453",
    "x402_asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "pricing_usd": "0.01",
    "category_ids": [1]
  }'

What we need from testers

List your x402 services on satring.com/submit. We want to see how well the directory handles real x402 service metadata.
Try paying with x402 on any premium endpoint. If you have an x402 client or agent with USDC on Base, hit our gated endpoints and let us know if the flow works.
Report bugs and friction. Open an issue on GitHub or comment here. We want to know what breaks, what's confusing, and what's missing.
Rate services you've used. The reputation system is only as good as the data feeding it.

Why this matters

The paid API market is splitting into two camps: Lightning (L402) and stablecoins (x402). Coinbase's Bazaar has 14,000+ auto-indexed x402 services, but zero curation, no ratings, no health checks. The Lightning side has several smaller directories. Nobody aggregates both protocols with quality signals.

Satring's goal is to be the independent trust layer that sits across both ecosystems. We don't intermediate payments (no money transmission). We provide discovery, reputation, and verification so agents and developers can find services worth paying for.

If you're building paid APIs or AI agents that consume them, we'd love your feedback.

Links:

Directory: satring.com
API Docs: satring.com/docs
GitHub: github.com/toadlyBroodle/satring
Submit a service: satring.com/submit

The L402 Ecosystem Has 100+ Live APIs. The Problem Is Finding Them.

satring — Fri, 13 Mar 2026 14:42:51 +0000

HTTP 402 "Payment Required" has been a reserved status code since 1997. For nearly 30 years, no browser or server actually used it. That changed recently.

What is L402?

L402 is a protocol that puts Bitcoin Lightning micropayments behind the 402 status code. The flow is simple:

Client requests a resource
Server returns 402 with a WWW-Authenticate header containing a Lightning invoice and a macaroon
Client pays the invoice (a few sats, fractions of a cent)
Client retries with Authorization: L402 MACAROON:PREIMAGE
Server verifies and returns the resource

No API keys. No OAuth. No credit cards. No accounts. The payment is the authentication.

# Example: hit an L402-protected endpoint
curl https://api.example.com/v1/data
# Returns: 402 + WWW-Authenticate: L402 macaroon="...", invoice="lnbc..."

# Pay the invoice with any Lightning wallet, get the preimage
# Then retry with the proof of payment
curl -H "Authorization: L402 MACAROON:PREIMAGE" https://api.example.com/v1/data
# Returns: 200 + data

The ecosystem is bigger than you think

There are now 100+ live L402 services in production across categories like:

Data: price oracles, mempool stats, on-chain analytics
Identity: Nostr trust scoring, PageRank, Sybil detection, spam classification
Finance: market signals, derivatives data, technical analysis
Media: image generation, transcription, content APIs
Search: web search, semantic search, domain lookups
Tools: URL shorteners, webhooks, compute services

Lightning Labs shipped lnget (a command-line L402 client) in February. Alby's PaidMCP SDK connects L402 services to AI agents via MCP. Coinbase and Cloudflare are pushing the parallel x402 protocol (same concept, stablecoins instead of Lightning). The infrastructure is real and growing fast.

The discovery problem

Here's the catch: there's no good way to find these services. Each L402 endpoint exists in isolation. If you're a developer building an L402 client, or an AI agent that needs to discover and pay for APIs autonomously, you have to know the exact URL in advance.

The closest things to a directory have been a static GitHub README (awesome-L402) and a couple of sites with fewer than 5 listings.

Building a searchable catalog

I built satring.com to fix this. It's a searchable directory of L402 services with:

Daily automated probing: every listed endpoint is checked for liveness and proper L402 support (valid 402 response + WWW-Authenticate header with macaroon challenge)
Verified status tags: confirmed (proper L402), live (reachable but no paywall detected), or dead
9 categories: Data, Finance, Identity, Media, Search, Social, Storage, Tools, Other
JSON API for programmatic access (agents can query it directly):

# search for services
curl https://satring.com/api/v1/search?q=sentiment

# list by category
curl https://satring.com/api/v1/services?category=finance

# full OpenAPI docs
# https://satring.com/docs

Domain verification: service owners can prove ownership via a .well-known/satring-verify challenge

Reading is free, no auth required. Submitting a service costs 1,000 sats, leaving a rating costs 10 sats. Both gated via L402 macaroons, which keeps the catalog clean without moderators or user accounts.

Why this matters for AI agents

This is the use case that motivated the project. An AI agent with an L402 client (like lnget or Alby's PaidMCP SDK) can:

Query satring's API to discover services matching a need
Get the endpoint URL and expected pricing
Hit the endpoint, receive the 402 challenge
Pay the Lightning invoice automatically
Call the service with the proof of payment

The entire flow is autonomous. No human needs to sign up for anything, provision API keys, or enter credit card details. The agent discovers, pays, and consumes services on its own.

Tech stack

FastAPI, SQLite, HTMX. Single lightweight server. Fully open source: github.com/toadlyBroodle/satring

If you're running an L402 service, you can submit it at satring.com/submit. If you're building L402 clients or agent tooling, the API is open and documented at satring.com/docs.

Would be interested to hear from anyone working in this space, especially on the agent service discovery side.