H-Series
H-Index
Register

Docs

The registry exposes a small HTTP API. Most consumers only need GET /endpoints.

Base URL

https://h-index.xr-utilities.ai

Search the registry

Query GET /endpoints with any of these parameters:

Categories: developer-tools, data, ai-models, infra, productivity, other.

Register a service

Registration requires a cryptographic signature from your wallet (TIP-712 on Hedera, EIP-712 on Base, ed25519 on Solana, or Xaman on XRPL) and payment in stablecoins (USDC, or RLUSD on XRPL). Click Register to get started.

Required fields: apiName, endpointUrl, description, pricing, ownerAccountId, registryTopicId, issuedAt, signature. Optional: category, mcpManifest, developerLogoUrl, developerDocsUrl, developerWebsiteUrl, developerGithubUrl, developerSocial, notifyUrl, slaReceiptRef.

Prove your execution (optional)

Set slaReceiptRef to advertise that your service anchors H-Seal proof-of-execution receipts, so delivery is a two-sided, tamper-proof record instead of your word: credibility in discovery, evidence for an SLA, and protection in a billing dispute. It takes no code in your service. Run the signing sidecar in proxy mode in front of your endpoint and every response is co-signed by your identity (setup: @xr-utilities/h-seal-provider), then set slaReceiptRef to the topic id or URL where you anchor. It is signed into your listing and shown as an attestation in discovery; it is self-claimed, not validated by H-Index at registration. Optional: omit it and your listing is unaffected.

Verify a listing on chain

Every active listing in /endpoints carries a consensusTimestamp and an ownerAccountId. Fetch the matching HCS-2 message from any Hedera mirror, validate the TIP-712 signature against the owner's public key, and you've verified the listing without trusting the registry operator.

Registry topic

All listings are anchored to HCS topic 0.0.10601198 on Hashscan.

Risk-event feed

GET /risk-events/:subject returns the risk events recorded for a subject, read from the shared H-Series audit topic. The products across the suite (H-Grant, H-Gate, H-Relay, H-Scope, and H-Agent) emit these events; H-Cert reads this feed to fold observed behavior into a subject's standing. The events are a record of observed behavior, not a score or a verdict.

Use with an AI agent (MCP + skills)

H-Index is part of the H-Series, exposed to agents as live tools by one hosted MCP server. Point any MCP client at it for the whole suite (discovery, registration, proof-of-execution, and more): 

claude mcp add --transport http h-series https://mcp.xr-utilities.ai/mcp

For the knowledge layer (which product for what, plus the client-side signing and x402 payment flows the tools do not do for you), add the H-Series skills in Claude Code: 

/plugin marketplace add XR-Utilities/h-series-skills
/plugin install h-series

Source and skill definitions: github.com/XR-Utilities/h-series-skills.

Use of the API is subject to the Terms of Service.