LLM Gateway

NEXUS Agent-as-a-Service on Cardano + Stellar | Price: $0.10/request | Accepts: ADA, DJED, iUSD, USDCx, USDM (Cardano) + USDC, XLM (Stellar)

When to use

Use when you need to call any LLM (GPT-5.2, Claude Sonnet 4.5, GPT-4o, Claude Haiku 4.5, GPT-4o-mini) through one endpoint. Supports tier-based routing (economy/standard/premium/auto) and OpenAI-compatible message format.

Steps

Option A: x402 Standard (Recommended)

1. Call the service endpoint without payment headers.
2. Receive HTTP 402 with WWW-Authenticate: Payment header AND x402 accepts[] array in response body.
3. Select a paymentRequirement from accepts[] matching your preferred network + asset.
4. Networks: cardano:mainnet (ADA, DJED, iUSD, USDCx, USDM), stellar:pubnet (USDC, XLM), sandbox (free).
5. Send payment to the payTo address for maxAmountRequired in the specified asset.
6. Stellar fee sponsorship: POST your signed XDR to https://ai-service-hub-15.emergent.host/api/mpp/stellar/sponsor — NEXUS pays gas, you need 0 XLM.
7. Retry with X-PAYMENT: \x3Cbase64url JSON {x402Version:1, scheme:"exact", network, payload:{tx_hash, currency}}> header.
8. Parse the JSON response and X-PAYMENT-RESPONSE header.

Option B: MPP Standard

1. Call the service endpoint without payment headers.
2. Receive HTTP 402 with WWW-Authenticate: Payment header listing all accepted currencies and amounts.
3. Pick your preferred chain + currency: Cardano (ADA, stablecoins) or Stellar (USDC, XLM).
4. Create payment: Masumi escrow (Cardano) or direct Stellar transfer.
5. Stellar fee sponsorship: POST your signed XDR to https://ai-service-hub-15.emergent.host/api/mpp/stellar/sponsor — NEXUS pays gas, you need 0 XLM.
6. Retry with Authorization: Payment \x3Cbase64url-credential> header.
7. Parse the JSON response and Payment-Receipt header.

Option C: Legacy Header

1. Send a POST request to the NEXUS API endpoint with your input.
2. Include the X-Payment-Proof header (Masumi payment ID or sandbox_test for testing).
3. Parse the JSON response and return the result.

API Call

curl -X POST https://ai-service-hub-15.emergent.host/api/original-services/llm-gateway \
  -H "Content-Type: application/json" \
  -H "X-Payment-Proof: $NEXUS_PAYMENT_PROOF" \
  -d '{"prompt": "Write a Python function to sort a list", "tier": "auto", "task_type": "code"}'

Endpoint: https://ai-service-hub-15.emergent.host/api/original-services/llm-gateway Method: POST Headers:

• Content-Type: application/json
• X-PAYMENT: \x3Cbase64url JSON> (x402 standard — recommended)
• Authorization: Payment \x3Ccredential> (MPP standard)
• X-Payment-Proof: \x3Cmasumi_payment_id> (legacy — use sandbox_test for free testing)

Accepted Currencies: ADA, DJED, iUSD, USDCx, USDM (Cardano) | USDC, XLM (Stellar) x402 Discovery: GET https://ai-service-hub-15.emergent.host/api/mpp/x402 (all services in native x402 format) MPP Discovery: GET https://ai-service-hub-15.emergent.host/api/mpp/discover Stablecoin Registry: GET https://ai-service-hub-15.emergent.host/api/mpp/stablecoins (includes on-chain policy IDs) Stellar Info: GET https://ai-service-hub-15.emergent.host/api/mpp/stellar (assets, recipient, fee sponsorship) Fee Sponsorship: POST https://ai-service-hub-15.emergent.host/api/mpp/stellar/sponsor (NEXUS pays Stellar gas — agents need 0 XLM)

External Endpoints

Security & Privacy

• All data is sent to https://ai-service-hub-15.emergent.host over HTTPS/TLS.
• No data is stored permanently; requests are processed and discarded.
• Payment proofs are verified on the Cardano blockchain via the Masumi Protocol.
• No filesystem access or shell execution required.

Model Invocation Note

This skill calls the NEXUS AI service API which uses LLM models (GPT-5.2, Claude Sonnet 4.5, GPT-4o) to process requests. The AI processes your input server-side and returns a structured response. You may opt out by not installing this skill.

Trust Statement

By using this skill, your input data is sent to NEXUS (https://ai-service-hub-15.emergent.host) for AI processing. Payments are non-custodial via the Masumi Protocol on Cardano. Only install if you trust NEXUS as a service provider. Visit https://ai-service-hub-15.emergent.host for full documentation.

Tags

llm, ai, gateway, multi-model, gpt, claude, router, cardano