Title: Show HN: I turned my homelab GPU into a paid API on Base mainnet

A developer has launched a self-hosted API on Base mainnet that sells LLM inference for USDC via the x402 HTTP 402 payment protocol, with a live endpoint running on a single RTX 5090 GPU and pricing starting at $0.01 per call. The reference implementation, released under an MIT license, includes a facilitator, FastAPI paywall middleware, and an MCP server, and has already processed its first external settlement of 0.12 USDC.

A self-hosted x402 paywall + facilitator for selling LLM inference over HTTP — running live on Base mainnet, paid in USDC, on a homelab GPU. This repo is the reference implementation behind a live endpoint. Any human or AI agent with a crypto wallet can buy a completion in one HTTP round-trip: no accounts, no API keys, no signup. Payment verifies on-chain before the model runs; settlement happens after — a failed request is never charged. $0.01 POST /premium/llm 27B open-weights model, 4K token cap $0.05 POST /premium/deep 8K tokens — double the thinking budget on the same 27B $0.10 POST /premium/vl 30B vision model, image understanding free GET /premium/balance live on-chain earnings transparency endpoint free POST /premium/trial 3 calls per wallet, sybil-limited by EIP-191 signature x402 HTTP 402 "Payment Required", revived by Coinbase lets software pay software. This repo is the smallest serious stack we found that does it self-hosted end to end : x402 facilitator.py — your own facilitator verify + settle . No hosted service, no middleman cut, no regional blocks. x402 paywall.py — FastAPI middleware: 402 with payment requirements → buyer signs → facilitator verifies → handler runs → settlement receipt in the response body X-PAYMENT-RESPONSE . x402 mcp server.py — MCP wrapper so Claude/desktop agents can purchase natively. scripts/x402 client demo.py — a working buyer in ~90 lines. buyer agent ──POST /premium/llm──▶ Caddy path allowlist ──▶ FastAPI paywall ▲ │ │ 402 + payment requirements │ verify via │ ▼ facilitator wallet signs ──────────────▶ on-chain Base │ handler runs AFTER verify settles AFTER success ≥400 cancels Security posture the interesting part for homelab operators : - The public internet reaches only the paywall routes. A reverse-proxy path allowlist 404s everything else — the rest of the machine fleet control, admin API, this repo's private origin is unreachable by design. - Wallet keys are age-encrypted at rest, decrypted in memory only. - Prompts are not logged or retained. The response dies with the connection. - Token caps per tier bound worst-case compute cost per call; every call is prepaid, so abuse is self-funding it pays us . pip install fastapi uvicorn x402 c web3 receive + facilitator wallets: age-encrypted JSON, decrypted at startup age-encrypt your wallet json → vault/x402 receive wallet.age uvicorn app:app --port 8900 app wires the middleware onto your routes Point a buyer at it: python3 scripts/x402 client demo.py "$URL/premium/llm" "Write a haiku about payments" - Live on Base mainnet chain 8453 , USDC settlement. - First real external settlement: 0.12 USDC and counting — see the balance endpoint on the live deployment. - Hardware: one RTX 5090 running an AWQ-quantized 27B. ~70% gross margin per $0.01 call after electricity. This is homelab infra, not an SLA product: best-effort uptime, one GPU, no data-retention paperwork — because there is no data retention. Positioning is exactly that: best-effort, cheap, keyless, and honest. License: MIT.