Summary: Pay-per-inference is finally practical because three enabling layers have matured at once: ultra-cheap L2 data availability for metered settlements, hardware- or ZK-backed verifiable inference receipts, and programmable wallets that can enforce policy-based, per-call payments. This post details how Heads of AI/Platform, Procurement, and Risk teams can ship a production-grade, contract-anchored “inference meter” in Q1–Q2 2026 with 7Block Labs.

The Rise of “Pay‑Per‑Inference”: Custom Blockchain Solutions for LLMs

Hook — The technical headache you’ve been putting off

Your AI platform runs across multiple providers (OpenAI Responses API, Azure OpenAI, vLLM on Blackwell/Hopper, and a private H100/H200 cluster). You can estimate monthly spend, but you can’t:

• Prove per-request usage to Finance for chargeback.
• Enforce “don’t pay if SLOs weren’t met” at the transaction level.
• Settle cross-organization micro-invoices without weeks of reconciliation.

Meanwhile, core assumptions keep shifting:

• OpenAI’s product surface moved to the Responses API and is sunsetting the Assistants API on August 26, 2026—breaking any metering tied to Assistants threads unless you migrate. (community.openai.com)
• Response headers (x-request-id, rate-limit headers) exist but aren’t consistently exposed in all SDKs or streaming flows, which complicates deterministic reconciliation across observability systems. (platform.openai.com)
• Some devs have seen sudden CORS or policy shifts on Responses API endpoints, reminding teams that “SDK logs ≠ audit-grade receipts.” (community.openai.com)

If your Q2 close expects accurate unit economics by product and customer—without this, you risk write-offs, failed vendor true-ups, and missed MBOs for “AI margin improvement.”

Agitate — What this breaks in the real world

• Missed deadlines: Without verifiable, per-inference receipts, Procurement can’t release staged payments on time, and Finance can’t move 10–20% of AI OPEX to direct COGS for revenue-aligned products before the board meeting.
• SLA exposure: If you can’t tie latency/TPS to a signed request ID, you can’t claw back on missed SLOs (e.g., 200 TPS/user target for interactive copilot sessions). Blackwell- and Rubin-class systems push tokens-per-second into new regimes; if you’re paying for “reasoning time” without control, your exposure balloons. (developer.nvidia.com)
• Vendor risk: Model/API transitions (e.g., Assistants → Responses), header/limits behavior, and policy enforcement are fluid; a single change can derail your metering pipeline and budget forecast. (community.openai.com)
• Compliance gaps: You need machine/verifier attestations for “where/how” inference ran. NVIDIA’s Secure AI (H100/H200) and CC-on stacks exist, but attestation/firmware maturity is nuanced and still evolving by SKU—Procurement and Risk want cryptographic proof, not promises. (developer.nvidia.com)

Solve — 7Block Labs methodology for Pay‑Per‑Inference

We implement Pay‑Per‑Inference as a composable, auditable “Inference Receipt Protocol (IRP)” that bridges technical verifiability and procurement‑grade settlement. Core pillars:

1. Verifiable Inference Receipts (VIRs)

• What we sign: hash(request body), model identifier/version, token usage, latency, SLO class, hardware/runtime fingerprint, and provider request IDs (e.g., OpenAI x-request-id when available). (platform.openai.com)
• How we verify:
  • TEE-backed attestation: Capture GPU/driver/CC mode (H100/H200 Secure AI) and record attestation quotes, with policy that payments only stream when attestation passes. (developer.nvidia.com)
  • zk-backed verification: For high-stakes workflows, use zkVMs (RISC Zero Bonsai, Succinct SP1) to prove parts of the pipeline (e.g., prompt canonicalization, token-usage accounting, or policy checks) and anchor a succinct proof with an onchain verifier. (risc0.com)
• Where receipts live: Onchain commitments with offchain payloads; we use Ethereum Attestation Service (EAS) schemas for issuer identity and revocations, making the IRP receipts portable across L2s. (attest.org)

1. Policy‑Based Settlement via Account Abstraction

• EIP‑4337 smart accounts plus Paymasters: enforce “pay only if VIR verifies” and “cap per‑customer daily spend,” support stablecoin gas sponsorship, and tenant‑specific wallets. (docs.erc4337.io)
• EIP‑7702 smart-accounts-on-demand (post‑Pectra): lets EOAs temporarily assume contract logic to batch calls and sponsor gas—ideal for providers issuing receipts and customers settling atomically. We implement safe delegation patterns to avoid the 7702 phishing pitfalls discussed post‑fork. (blockworks.co)
• Streaming or per‑call micropayments: integrate continuous payment rails (e.g., Superfluid CFAv1) for “pay as tokens stream” or micro‑escrow release per receipt. (superfluid.gitbook.io)

1. Ultra‑low‑cost data anchoring on L2 blobs

• Blob economics after Dencun and Pectra: post‑2025 blob capacity increases (6/9 blobs target/max) slashed L2 DA costs; we structure receipts so rollups post blobs cheaply while remaining queryable for audits. (panewslab.com)
• Outcome: Storing metering commitments now costs orders of magnitude less than calldata, opening the door for per‑call records instead of batched, lossy summaries. (coinmarketcap.com)

1. Privacy‑Preserving Access for Consumer Data

• OHTTP gateways (RFC 9458) to decouple user IP from inference requests where required by policy without sacrificing per‑request accountability—important for regulated markets and consumer telemetry. (ietf.org)

1. FinOps‑grade Observability and Chargeback

• We wire OpenTelemetry counters for tokens, latency, and cost per request and reconcile with VIRs; we use provider request IDs when present and our own X‑Client‑Request‑Id otherwise. For open‑source stacks (vLLM), we patch streaming metrics gaps. (oneuptime.com)

1. Hardware & Runtime Optimization Hooks

• We align procurement with hardware reality. Blackwell GB200/Rubin families compress cost per 1M tokens by 5–15x in measured benchmarks versus Hopper; we expose those curves in billing so your unit economics improve as your cluster modernizes. (developer.nvidia.com)

Architecture at a glance

• Client/API layer:

  • Provider SDKs (OpenAI Responses, Azure OpenAI) + internal vLLM/TensorRT‑LLM gateways.
  • OHTTP gateway (optional) for privacy-preserving egress. (ietf.org)

• Metering & proof layer:

  • Token/latency counters via OpenTelemetry; capture provider headers (x-request-id, rate limits).
  • VIR builder computes commitments and assembles TEE/zk evidence.
  • ZK options: Succinct SP1 pipelines for policy verification; Bonsai for scalable proving. (blog.succinct.xyz)

• Settlement layer:

  • EAS schemas for issuers, policies, attestation of hardware/keys; receipts posted to L2 as blob-backed data. (attest.org)
  • ERC‑4337/7702 wallets for policy-based payments and sponsorship. (docs.erc4337.io)

• Governance & revocation:

  • EAS revocation and dispute workflows; optional third-party attestation registries (EF ESP RFP points to where the ecosystem is headed). (esp.ethereum.foundation)

Practical examples you can implement this quarter

1. “Only pay for compliant, attested inferences”

• Hardware: H100/H200 in CC‑On mode or GB200 with Secure AI stack, with attestation verification enforced by the Paymaster; if attestation fails, the micropayment stream halts. (developer.nvidia.com)
• Onchain: A settlement contract checks (a) EAS issuer signature, (b) attestation quote hash, (c) SLO fields, then releases USDC-per‑call from a pre‑funded channel.

1. “Metered RAG for supplier contracts with policy guardrails”

• Architecture: IRP records include RAG context window hash and per‑call token counts; queries under a “no-PHI leaves boundary” policy are proved via SP1 circuits that validate redaction steps and policy flags before payment. (succinct.xyz)

1. “Cross‑provider cost governance with predictable unit economics”

• Blackwell/GB200 benchmark data shows >10x reductions in cost/1M tokens vs Hopper at interactive TPS; tie your internal chargeback rate to hardware class in the VIR so business units see lower rates as you upgrade. (developer.nvidia.com)

1. “Privacy‑preserving consumer features”

• Use OHTTP to anonymize consumer prompts while still stamping VIRs with your gateway’s request hash; Procurement accepts this as privacy‑compatible evidence of work for per‑call invoicing. (ietf.org)

Best emerging practices (Jan 2026)

• Prefer “commitment-first” receipts: Hash the entire request + token usage details and post the commitment immediately; link full payloads via content-addressed storage later for audits.
• Split trust between TEE and ZK: Use TEEs for speed (attestation) and ZK to independently verify policy transformations or accounting logic (e.g., no “hidden” reasoning tokens billed). SP1’s real-time proving strides make this viable for selective checks today. (blog.succinct.xyz)
• Anchor to blobs, not calldata: After Dencun and Pectra’s blob expansions, anchoring per‑call receipts is economically sustainable. Design for blob pruning windows and maintain a separate archival store. (coinmarketcap.com)
• Harden AA patterns post‑Pectra: EIP‑7702 brings UX superpowers and new phishing surfaces—require explicit, short‑lived delegations; display 7702 ops distinctly in wallet UIs; and use EAS‑pinned code hashes for allowlists. (coindesk.com)
• Instrument the headers you’ll need in disputes: Log x-request-id, x‑ratelimit‑*, openai‑processing‑ms, plus a client‑supplied X‑Client‑Request‑Id to align third‑party proofs with your internal traces. (platform.openai.com)
• Route for cost/SLO, not just latency: Multi‑SLO schedulers and semantic routers cut reasoning-token waste by ~2x without accuracy loss; bake these savings into chargeback rates per class. (arxiv.org)

Target audience and required keywords to include

• Head of AI/Platform Engineering (Fortune 1000): “SLO-aware routing,” “speculative decoding,” “prefill chunking,” “TensorRT‑LLM,” “NVFP4/FP4 quantization,” “vLLM streaming metrics,” “OpenTelemetry span events.” (developer.nvidia.com)
• Procurement & Vendor Management: “metered billing,” “per‑call receipts,” “policy‑based settlement,” “PO-backed escrow,” “unit economics per 1M tokens,” “chargeback reconciliation.”
• Finance/FinOps: “cost-per-token curves,” “OPEX→COGS reclassification,” “variance analysis by model/hardware,” “SaaS-style ARR on usage,” “blob-backed audit trail.” (panewslab.com)
• Risk/CISO/Data Governance: “Confidential Computing attestation,” “TEE quotes,” “OHTTP privacy boundary,” “EAS issuer registries,” “policy proofs via zkVMs.” (developer.nvidia.com)

Why this is now economically viable

• L2 DA costs: Proto‑danksharding blobs (EIP‑4844) and Pectra’s blob target increase collapsed L2 posting costs; per‑inference anchoring is now cents-to-sub‑cents at scale. (coinmarketcap.com)
• Hardware curve: Blackwell GB200 materially compresses “cost per 1M tokens,” and Rubin NVL72 announced for 2H 2026 pushes another 5–10x for MoE; your billing policy should expose and pass through these gains. (developer.nvidia.com)
• AA maturity: ERC‑4337 production wallets and Pectra’s 7702 let you implement paymasters, sponsored gas, and controlled delegations without L1 consensus changes. (docs.erc4337.io)

Implementation roadmap (8–10 weeks to first invoices)

Week 1–2: Architecture and schema design

• Define VIR/EAS schema (issuer, attestation types, SLO classes).
• Select L2(s) and blob posting cadence.
• Choose proof mode: TEE-only vs TEE+ZK for specific controls.

Week 3–4: Wallets and settlement contracts

• Deploy ERC‑4337 smart accounts and Paymasters with per‑tenant spend caps.
• Add EIP‑7702 delegation helpers with explicit UI warnings and EAS allowlists. (coindesk.com)

Week 5–6: Observability integration

• Wire OpenTelemetry for token, cost, and latency metrics; capture provider headers (x-request-id, x‑ratelimit‑*). (platform.openai.com)
• Patch vLLM streaming metrics or add a sidecar to emit per‑response usage.

Week 7–8: Proofs and privacy

• Integrate NVIDIA Secure AI attestation validation; wire fail‑closed payment. (developer.nvidia.com)
• Optional: OHTTP gateway for consumer prompts (regulatory markets). (ietf.org)
• Optional: SP1/Bonsai proof-of-policy for redaction/billing logic. (blog.succinct.xyz)

Week 9–10: Pilot and GTM instrumentation

• Run a 2–3 provider pilot with shadow invoices and “pay‑only‑if‑verified” toggled on.
• Publish internal GTM dashboards: cost/1M tokens by model/hardware, SLO pass rate, unbilled tokens, days-to-reconcile.

GTM metrics you can hold us to

• Time-to-invoice: Reduce from T+30 to T+1 business day for usage-based SKUs (using VIR commitments + blob anchoring).
• Unreconciled usage: <0.5% of tokens unaccounted per billing cycle (header alignment + VIR hashing). (platform.openai.com)
• SLA-compliant payments: 100% of payouts gated by SLO evidence; clawback window enforced automatically via EAS revocation events.
• Margin uplift: Show unit-cost curves that track hardware class—e.g., GB200 vs H200—so internal chargeback falls as clusters upgrade. Benchmarks report 5–15x reduction in cost/1M tokens vs Hopper; we expose that in dashboards. (developer.nvidia.com)

Where 7Block Labs fits

• Strategy to code: We design the IRP schema, build/verifier contracts, and integrate with your providers—no vendor lock‑in.
• Security‑first delivery: We harden AA patterns (4337/7702), model attestation checks, and proof verifiers, and run pre‑launch threat modeling.
• Integration where it matters: SAP/NetSuite export, data warehouse sinks, and privacy controls that your CISO signs off on.

Explore how we do it:

• Our custom blockchain development services for enterprise‑grade, policy‑based settlement.
  https://7blocklabs.com/services/blockchain-development-services
• End‑to‑end web3 development services to stand up AA wallets, paymasters, and L2 integrations fast.
  https://7blocklabs.com/services/web3-development-services
• Security audit services for AA, Paymasters, and receipt verifiers before you go live.
  https://7blocklabs.com/services/security-audit-services
• Blockchain integration for ERP/BI/FinOps, including attestation registries and data pipelines.
  https://7blocklabs.com/services/blockchain-integration
• Smart contract development to codify VIR verification, dispute windows, and policy‑based payouts.
  https://7blocklabs.com/solutions/smart-contract-development
• Cross‑chain solutions when you need multi‑L2 receipts or to settle to different jurisdictions.
  https://7blocklabs.com/services/cross-chain-solutions-development

Brief in‑depth details worth bookmarking

• Pectra (May 7, 2025) introduced EIP‑7702—EOAs can temporarily act like smart wallets, enabling batched calls and sponsored gas; adoption surged quickly, but so did phishing attempts, so UI/allowlist hygiene is critical. (blockworks.co)
• L2 blob economics: Dencun/EIP‑4844 made posting data to L1 via blobs ~10–100x cheaper than calldata; Pectra raised blob targets (6/9), making per‑call metering feasible on rollups. (coinmarketcap.com)
• Verifiable inference: SP1 hit real‑time proving on commodity GPUs; Bonsai provides enterprise-grade proving service—together these make “proof‑carrying” inference practical for selected invariants (not full token-level traces yet). (blog.succinct.xyz)
• Confidential compute: NVIDIA Secure AI GA details CC stacks for H100/H200; ensure your bill‑of‑materials (CPU TDX/SEV‑SNP, driver, VBIOS) is attested and logged in VIRs. (developer.nvidia.com)
• Inference cost curves: Blackwell GB200’s measured cost-per‑million‑tokens drops are dramatic; Rubin NVL72 (announced CES 2026) targets another order-of-magnitude on MoE. Build those breakpoints into your PMF and pricing tiers. (developer.nvidia.com)
• Provider headers: OpenAI’s debugging page documents x‑request‑id and rate-limit headers; always propagate or synthesize X‑Client‑Request‑Id for end‑to‑end correlation. (platform.openai.com)

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Bold money phrase: With verifiable inference receipts and policy‑based settlement, you stop guessing at AI margins and start enforcing them per call.

• If you lead AI Platform or Procurement, we’ll ship a pilot that posts blob‑anchored receipts, pays only on verified SLOs, and reconciles to your ERP in under 10 weeks.
• If you’re already at scale, we’ll tie chargeback to your hardware class (Hopper → Blackwell → Rubin) so every GPU refresh automatically lowers internal rates with cryptographic proof.

Personalized CTA: If you’re the Head of AI Platform at a U.S. enterprise processing >50M tokens/day across OpenAI + vLLM, and Finance has asked you to reclassify 12% of AI OPEX to COGS before your April 30, 2026 close, reply “Inference Receipts” with your stack (providers, L2s, wallet infra). We’ll send a tailored IRP schema and a 2‑sprint plan to have your first “pay‑only‑if‑verified” invoices live by March 31.