VoltageGPU vs Spellbook

Spellbook is genuinely good at one specific thing: living inside Microsoft Word and making the drafting experience faster. The add-in surfaces clause suggestions while the associate is still typing the next sentence, redlines flow into the document the way a senior partner's comments would, and the market benchmarking shows where a clause sits relative to Spellbook's aggregated corpus of contracts. If the firm's contract production already happens in Word and the volume justifies it, Spellbook removes friction from the drafting workflow in a way nothing else in the legal AI category currently matches. That is not a marketing claim, it is the correct read of where their product team has invested.

The trade-off lives one layer down from the UX. Every clause suggestion is an AI call. Every redline is an AI call. Every market-benchmark query is an AI call. And every one of those calls sends the relevant portion of the contract text to OpenAI as a sub-processor, per Spellbook's own published Data Processing Agreement. The legal entity drafting the contract is in your jurisdiction; the AI processing the contract is in OpenAI's. For most general commercial drafting that is an acceptable trade, the contract content is not jurisdictionally sensitive and the speed gain is worth the sub-processor chain. For matters where the contract names the client, the deal terms, the price, the parties, the litigation strategy, or anything covered by attorney-client privilege under a strict reading, that sub-processor chain is the problem worth solving.

VoltageGPU does not try to win the Word UX fight. We replace the AI layer that sits behind the drafting tool, not the drafting tool itself. The same Contract Analyst capabilities, clause review, redline suggestion, risk flagging against firm playbook, market-comparable analysis on the firm's own corpus, run with the model inside an Intel TDX enclave at our inference provider. The contract text crosses the wire encrypted to our servers, which see it in clear while the agent prepares the request, then reaches a model whose memory the host cannot read. The legal entity processing the contract is VOLTAGE EI in Solaize, France, under a French-law Article 28 DPA; our inference provider and hosting are US companies (listed on /legal/subprocessors). The threat model is different for the model's host, by silicon, not by promise.

A sub-processor listing in a vendor DPA is a routine industry artifact, every SaaS legal-tech tool that calls a hosted AI lists the underlying model provider. Spellbook's public DPA lists OpenAI in that role, the same way most of their direct competitors do. The clause itself is unremarkable. What it means operationally for a firm's data flow is worth being explicit about, because the implication tends to get glossed over in procurement reviews.

When an associate is drafting an NDA in Word and Spellbook suggests an alternative confidentiality clause, the contract content adjacent to that clause leaves the associate's machine, transits to Spellbook's infrastructure on AWS US, gets prepared into an OpenAI API call, transits again to OpenAI's infrastructure (Azure-hosted, US), and an OpenAI model produces the suggested clause. That is three jurisdictions touched by one keystroke: the associate's, Spellbook's (Canada-incorporated, AWS-US-hosted), and OpenAI's (Delaware, US). For straight commercial drafting on non-sensitive subject matter this chain is fine. For a contract where the deal terms are price-sensitive, or where the parties are publicly traded and the agreement is pre-disclosure, or where the contract content itself is privileged communication, the privilege analysis is no longer simple, and the data-flow disclosure to the client becomes a real document rather than a checkbox.

With VoltageGPU the data flow is shorter, not single. The contract text goes to VoltageGPU (VOLTAGE EI, SIREN 943 808 824 00016), whose servers see it in clear while the agent works, then to a model running in a TDX guest at our US inference provider, where Intel's CPU encrypts the model's memory with a key the host does not hold. GET /v1/attestation returns the TDX quotes of the serving instances, which the firm can verify offline against an Intel-root certificate; they prove those instances are TDX guests, not that a given review ran on one of them. The firm's data-flow disclosure to the client therefore names our relay and our inference provider, without OpenAI, and with hardware evidence about the model's host.

Where Spellbook wins, honestly: the Word integration is the best in the category. The add-in renders inline suggestions during drafting at a latency that does not interrupt flow, the redline workflow respects the way Word users already work with track-changes, the clause library and playbook tooling are mature, the market-benchmarking corpus is large enough to give real signal on whether a clause sits inside or outside common-market terms, and the user onboarding for an associate already living in Word is essentially zero. For a firm whose practice volume sits squarely on contract drafting in Word and whose matter sensitivity does not require hardware-enforced privacy, Spellbook is a defensible market choice and a good product.

Where Spellbook does not win: per-seat pricing escalates fast at firm scale. Team tier at around $40 per seat per month is fine at three or five associates; Pro at $199 per seat per month at ten seats is $1,990 per month for a mid-size practice; Enterprise at around $350 per seat per month with a six-month minimum commit (both the price and the commit were tightened in late 2025) crosses into RFP territory for any firm beyond twenty-five lawyers. The OpenAI sub-processor relationship is unavoidable on every AI call. There is no Intel TDX path, no GPU TEE, no attestation chain, and no EU operating entity on the contract; the operator on the DPA is Canadian and the underlying compute is AWS US.

VoltageGPU's positioning is the inverse of those four points. The Starter plan at $349 per month is a flat team subscription with three seats included, so three associates run at less than the cost of three Spellbook Pro seats. The Professional plan at $1,199 per month covers ten seats and nine agents (Contract Analyst plus Due Diligence, Compliance, Legal Research, and four more) at the same headline number where Spellbook Pro at ten seats lands around $1,990 per month for one tool. The model runs inside Intel TDX, whose instances you can attest, the operator is a French entity, and the DPA is signed against French law. The trade-off the firm makes is real and worth naming: VoltageGPU does not ship a Word add-in, so the in-Word drafting flow has to be wired via the OpenAI-compatible API or substituted with our web UI / Telegram interface. For firms whose drafting volume sits inside Word that is friction worth weighing. For firms whose sensitivity profile makes the OpenAI sub-processor chain a problem worth solving, it is the right trade.