Relex と Claude vs Westlaw
顧客、データ、そして事務所を、あなたのものに。
Westlaw is Thomson Reuters' legal-research service: a proprietary, editorially enhanced database of case law, statutes and secondary sources, with headnotes and KeyCite, and AI-Assisted Research layered on top, sold by subscription through sales. Relex is not a research database you rent. It gives the Claude you already pay for the whole matter as a formal ontology, and grounds every citation in verbatim text it fetches and caches from official and free sources, which a verifier then enforces. The law you cite is checkable, and the client's identity never reaches a model.
一目でわかる比較
| 観点 | Relex | Westlaw |
|---|---|---|
| 顧客データはどこへ行くか | 何かがデバイスから出る前に、ブラウザ内で暗号化されます。モデルが目にするのは [Party 1] だけです。 | A proprietary, editorially enhanced research corpus (headnotes, KeyCite), licensed by subscription; Thomson Reuters publishes an enterprise security and compliance program. |
| 誰の AI が動かすか | ご自身の Claude または Claude for Legal を MCP と OAuth で持ち込めます。推論はあなたのものです。 | AI-Assisted Research and CoCounsel features run on Thomson Reuters' own stack. Westlaw does not publicly describe bringing your own model or agent into the product. |
| 今日試せるか | サインアップして、数分で実際のケースを動かせます。無料で試せ、カードは不要です。 | Quote-based subscription through sales; no public pricing. |
| 顧客は誰のものか | パートナーネットワーク：顧客を所有し、手数料 0% で 100% を手元に残します。 | A research subscription, not a client-ownership or referral model. |
| ケースの構造 | 当事者、争点、請求、法令、事実からなる正式なオントロジーです。 | A search interface over case law, statutes, regulations and secondary sources. |
| あなたのノウハウ | モデルが検索するプライベートなテナントごとの索引です。モデルが保持したり学習に使ったりするコピーではありません。 | Your notes and folders inside the platform; the corpus itself is Thomson Reuters' licensed content. |
| 始め方 | ブラウザで数分、単体でも、ご自身の Claude とでも。 | Sales process and subscription setup. |
この比較は、2026 年 7 月 時点での各製品自身の公開されたポジショニングを反映しています。Westlaw はそれぞれの所有者の商標であり、このページは独立した比較です。
正反対の賭け
Westlaw is the bet that legal knowledge is a proprietary database you subscribe to, with the publisher's editorial layer between you and the law. Relex takes the opposite bet. The law is grounded from official and free sources into verbatim cached text, a verifier rejects any citation that is not backed by that text, and the reasoning belongs to the Claude you already pay for. You are not renting access to the law; you are grounding your own work in it.
この組み合わせが勝つ理由
A research database can return authorities. It cannot run your matter: the parties, issues, claims, statutes and facts as a formal ontology, with your own know-how indexed privately alongside. Relex gives your Claude that whole structure and grounds its drafting in verbatim law it caches from official and free sources, so the citations are filing-grade and checkable, while the real names stay encrypted in your browser. For US local law it searches LOCUS, 2.2M municipal and county ordinance sections, and fetches the exact section text to cite.
受任を所有し、顧客を所有する
Research is one step of a matter, not the whole of it. Clients reach your practice by email, by WhatsApp or SMS, or through a guest link, and what they tell you becomes a structured case the agent picks up. Research, drafting, native cryptographic e-signature and invoicing run in one workspace. Through the Partner Network you stay the merchant of record through Stripe, at a flat $99 per month and 0% commission on what your clients pay you.
Relex はソフトウェアプラットフォームです。法律事務所ではなく、弁護士を置き換えるものでもなく、法的助言を提供するものでもありません。
What you actually pay
Relex publishes its price. It is free to start, needs no credit card, and runs on the Claude subscription you already pay for, so there is no per-seat AI licence stacked on top. If you bill your own clients through the Partner Network, you stay the merchant of record and keep 100% of what they pay you, at a flat $99 per month with 0% commission. No per-matter platform cut, and no enterprise quote to negotiate.
Westlaw is a quote-based research subscription. Relex adds no research-database licence: it grounds citations in verbatim text from official and free sources and runs on the Claude you already pay for, at a flat $99/mo with 0% commission.
よく聞かれる質問
Is Relex a legal-research service like Westlaw?
No. Relex does not resell a proprietary law database. It grounds your Claude's drafting in verbatim law it fetches and caches from official and free sources, with a verifier that rejects any citation not backed by cached text. Research is one grounded step inside running the whole matter, not a subscription you browse.
Where does the law Relex cites come from, and can I trust it?
From official and free sources, cached verbatim, and enforced by a verifier before a draft can cite it. Community legal packs that relied on model memory found roughly 30% of their citations wrong; Relex's citation discipline is mechanical, not aspirational, so filing-grade citations are grounded in text, not recalled.
Does Relex cover local and international law?
Yes. For US local law it searches LOCUS, 2.2M municipal and county ordinance sections, and fetches exact section text. Across jurisdictions it discovers authorities through official and free channels and grounds the verbatim text before citing.
Which one can I try today?
Relex. Signing up is free, takes one click, and needs no credit card. Westlaw is quoted and set up through Thomson Reuters' sales team.
What does legal research cost per search on Relex?
Nothing per search. Relex grounds citations by fetching and caching verbatim text from official and free sources on the Claude you already pay for — there is no per-search charge, no plan-coverage tier, and no "out of plan" document to decide whether to open.
How much does Relex cost compared with the others?
Relex is free to start, then a flat $99 per month with 0% commission if you bill your own clients through it, on top of the Claude plan you already have and with no separate per-seat AI fee. Most tools compared here quote enterprise pricing through sales or charge per user for their own AI. None of them publishes a referral or marketplace take rate; Relex publishes its own: 0%.
その他の比較
法律の周りの作業を自動化する。弁護士であり続ける。
顧客、データ、そして事務所を、あなたのものに。ブラウザで始めるか、ワンステップでご自身の Claude を持ち込んでください。貼り付けるキーはありません。