Introduction
What VDM Nexus is, what signed inference means, and why you'd use it.
VDM Nexus is signed inference for AI agents: an inference call paired with an on-chain payment and a cryptographic receipt of exactly what the model returned.
The wedge in one paragraph: when an autonomous agent makes a decision based on an LLM call, downstream systems usually have to trust that the agent's report of "the model said X" is accurate. A signed inference returns a hash-bound receipt of the prompt and the response, signed by the inference provider, alongside an on-chain payment that proves the call was real. The agent can hand that receipt to another agent, a smart contract, or a human auditor — and they can verify it without trusting the agent.
What's live
| Surface | Description |
|---|---|
@vdm-nexus/sdk | Lean prepaid flow. Ed25519-signed requests, debited from a credits balance. Two runtime deps. |
@vdm-nexus/x402 | Pay-per-call. Every request settles an x402 USDC transfer on Solana (or Base) before the model runs. Includes the 5-check receipt verifier. |
@vdm-nexus/paywall | Drop-in middleware for Express, Hono, and Next.js. Wrap any handler; every paid call returns a signed Ed25519 receipt of what your handler produced. |
@vdm-nexus/mcp | MCP server that exposes signed inference as a tool. Drop into Claude Desktop, Cursor, or any MCP-aware client — your agent inherits paid calls + verifiable receipts with no code change. |
nexus.vdmnexus.com/api/v1/chat/completions | OpenAI-shape endpoint gated by x402. Self-hosted facilitator. Multi-chain via body.network (solana, base, base-sepolia). |
nexus.vdmnexus.com/api/v1/inference | Original signed-request endpoint for the prepaid flow. |
verify.vdmnexus.com | Hosted verifier — paste a receipt, get a green/red verdict on each of the five checks. No install, no account. See also @vdm-nexus/x402's verifyReceipt for in-process verification. |
Today: Solana mainnet + devnet + Base / Base Sepolia. The Solana mainnet rail is live behind a KMS-signed facilitator; devnet stays up for free testing.
Pick a starting point
- New to the concept? → Why VDM Nexus
- Want the system overview? → Architecture
- Want code? → Quickstart — or skip straight to the hosted playground for a no-install signed-inference call.
- Plugging into Claude Desktop / Cursor? →
@vdm-nexus/mcpreference has the config blocks and a worked end-to-end example.