spArxx.io | Zero-Knowledge Blockchain Timestamping

Built for human creators - Register a timestamp on Polygon proving you made something, the moment you did.

CommunityOnlineNo sign-inGlobalFreeRead-only

What it can do

  • Create Timestamp: Compute the SHA-256 hash of the file locally - the file itself is never uploaded, and spArxx.io never stores it. Call this with that hash plus basic file metadata to register a prove
  • List Evidence: Returns every evidence item owned by the calling account, newest first, as a summary (no full receipt data, call get_evidence for the complete receipt kit on a specific item). Use this
  • Get Evidence: Returns the complete receipt kit for a single evidence item: hash, file metadata, status, and, once the on-chain job has settled, the blockchain transaction hash and explorer URL. Poll t

What data it sees

Do you need an account

No: the server works without sign-in

Built for human creators - Register a timestamp on Polygon proving you made something, the moment you did. Your file is never uploaded, watermarked, or altered: only its cryptographic fingerprint ever reaches spArxx.io, zero-knowledge by design. What comes back is a timestamp: your independently verifiable record of having registered it first.

Built on MCP (the same open standard Claude and other AI assistants use for secure, authenticated tool access), the spArxx.io server lets your AI register timestamps, check your balance, retrieve receipts, and verify blockchain anchors, mid-conversation, no app-switching. Every timestamp anchors to the Polygon blockchain, independently verifiable forever after ... no trust in spArxx.io required beyond the public chain itself.

spArxx.io is built for human creators, and that shows up in how it's provisioned ... not just in its purpose: connecting via MCP gets your AI access to the tools, but a human still provisions the account behind it. That's a deliberate choice, not unfinished friction. Minimal human involvement is required, but not zero ... that's what keeps the registration meaningful.

At a glance:

  • Chain: Polygon
  • Privacy: Zero-knowledge. Your file's contents never reach spArxx.io, only its cryptographic fingerprint does
  • Cost: 20 spArks (~$0.20) per agentic timestamp (the lowest rate on the platform).
  • Access: OAuth, human-provisioned account required

How to connect

How to connect spArxx.io | Zero-Knowledge Blockchain Timestamping to Claude

The server address to paste into Claude settings:

https://sparxx-io--comms-717a.run.tools

  1. Open Claude (claude.ai or the desktop app).
  2. Go to Settings → Connectors.
  3. Click Add custom connector.
  4. Paste the server address copied below into Remote MCP server URL and click Add.
  5. In a chat, click + → Connectors and switch the new connector on.

Custom connectors are available on Free, Pro, Max, Team and Enterprise plans (Free is limited to one). On Team and Enterprise an organization Owner adds the connector first under Organization settings → Connectors.

Authorization

After you click Add, a sign-in window for the service opens. Sign in with your own account and approve access. Claude never sees your password.

How to connect spArxx.io | Zero-Knowledge Blockchain Timestamping to ChatGPT

The server address to paste into ChatGPT settings:

https://sparxx-io--comms-717a.run.tools

  1. Open ChatGPT in a browser (chatgpt.com). A Plus, Pro, Business, Enterprise or Edu plan is required.
  2. Turn on developer mode once: Settings → Apps → Advanced settings → Developer mode.
  3. Open Settings → Connectors and click Create.
  4. Fill in the form: Name (anything), Description (one line about what the service does), MCP server URL (copy it below).
  5. Under Authentication choose OAuth if the service requires sign-in, otherwise None. Click Create.
  6. In a new chat open + → Apps/Connectors and enable the connector.

OpenAI has renamed this section before (Connectors → Apps/Plugins). If the label differs, search settings for "developer mode". On Business/Enterprise workspaces an admin must allow custom connectors first.

Authorization

On first use ChatGPT opens the service's sign-in window. Sign in and approve access.

How to connect spArxx.io | Zero-Knowledge Blockchain Timestamping to Cursor

The server address to paste into Cursor settings:

https://sparxx-io--comms-717a.run.tools

Fastest: click Open in Cursor below and confirm the prompt.

Manually:

  1. In Cursor open Settings → Cursor Settings → MCP and click Add new global MCP server.
  2. Paste the JSON copied below into ~/.cursor/mcp.json (per project: .cursor/mcp.json in the repo root).
  3. Save the file. The server appears in the MCP list; authorize it there if asked.

Authorization

If the service needs sign-in, an authorize button appears next to the server in the MCP list.

Server tool list (6)

Raw names from tools/list. Only developers need these.

create_timestampCompute the SHA-256 hash of the file locally - the file itself is never uploaded, and spArxx.io never stores it. Call this with that hash plus basic file metadata to register a provenance timestamp. This deducts spArks from the account (dynamic cost. Call get_pricing or get_balance first if you want to pre-check spend; a 402 response here means ins...
list_evidenceReturns every evidence item owned by the calling account, newest first, as a summary (no full receipt data, call get_evidence for the complete receipt kit on a specific item). Use this to find an evidence_id when the caller only knows a file name, or to check on recent timestamping activity.
get_evidenceReturns the complete receipt kit for a single evidence item: hash, file metadata, status, and, once the on-chain job has settled, the blockchain transaction hash and explorer URL. Poll this after create_timestamp until status is 'submitted', then save the full response alongside the original file as the durable proof-of-timestamp record. This is th...
get_balanceCall this before create_timestamp if you want to pre-check that the account can afford the operation and explain a likely 402 in advance, rather than reacting to one after the fact. Combine with get_pricing to compare balance against cost.
get_pricingPublic pricing reference. Does not require a user credential, only the channel Consumer-Token. Returns the current cost (in spArks) of a timestamp operation and the credits-to-USD exchange rate. Both timestamp_register (standard) and timestamp_register_agentic (MCP agent calls) are always returned, regardless of the caller's own auth, so this is a...
verify_certificateUnauthenticated. No Consumer-Token or user credential required. Any agent can verify any spArxx.io timestamp proof this way, which makes it a discovery surface as well as a verification tool: given a tx hash from a certificate or receipt kit, this confirms the proof is real and returns the public receipt data (identity claim redaction now follows t...