Contract Review Software: Web-Based vs Microsoft Word Plugins — Which Is Right for Your Firm?

July 2026 · 9 min read

If you're a solo or small-firm attorney looking to streamline contract review, you've likely noticed that most AI contract review tools fall into one of two camps: Microsoft Word plugins (Spellbook, LegalOn) or web-based platforms (ContractPeer, TheLawGPT). Each approach has real trade-offs, and choosing the wrong one can cost you time, money, or both.

This guide breaks down the differences honestly — what each approach does well, where it falls short, and how to decide which fits your practice.

Why This Choice Matters

Contract review is one of the highest-volume tasks in a small practice. The average solo attorney reviews dozens of contracts per month — NDAs, MSAs, employment agreements, vendor contracts, software licenses. A tool that saves even 15 minutes per contract adds up to hours every week.

But the tool only saves time if it actually fits the way you work. A Word plugin that works beautifully in one scenario can be a bottleneck in another, and a web-based tool that seems simpler on the surface may lack features you need.

How Each Approach Works

Word Plugin Tools

Tools like Spellbook and LegalOn install as add-ins inside Microsoft Word. You work inside a document, and the AI flags issues, suggests redlines, and proposes language — all without leaving Word. The advantage is obvious: if you already draft and review contracts in Word, the AI feels like part of your existing workflow.

But there are real limitations:

• Windows + Word required. You cannot use these tools on a Mac without Word for Mac, and the experience varies. Linux, Chromebook, or tablet users are entirely excluded.
• Installation friction. Every attorney in the firm needs the add-in installed. IT may need to approve it. Updates roll through Word's add-in store, which can lag.
• No mobile or offline access. You can't upload a contract from a phone, a client's portal, or an email attachment and get instant analysis.
• License cost per seat. Most Word-plugin tools charge per attorney per month. A solo may pay $99/month for one seat; a firm of five pays $495/month.
• File-format limited. Most handle only .docx files. PDF-only contracts (common from clients) require conversion before analysis.

Web-Based Tools

Platforms like ContractPeer operate entirely in a browser. You upload a contract (PDF, DOCX, or TXT) on any device — desktop, laptop, tablet — and get analysis back in seconds. No installation, no OS dependency, no file conversion.

Key advantages:

• Any device, any OS. Windows, Mac, Linux, Chromebook, tablet — if it has a browser, it works.
• No installation. Upload a contract and get results instantly. Nothing to configure, nothing to update.
• Multi-format support. PDF, DOCX, TXT. Client sent a scanned PDF? No conversion needed.
• Free low-commitment entry. Try the tool with a single contract paste — no signup, no credit card.
• No per-seat pricing. Accounts not tied to device installations.

The trade-off: web-based tools don't integrate with Word's drafting interface. If you need AI-suggested redlines inserted directly into your working document, web-based tools require copying the suggestions back into Word manually.

When to Choose a Word Plugin

A Word-plugin tool makes sense if:

• You do all contract work inside Microsoft Word and switching contexts feels disruptive.
• You need AI-powered redlining — suggested edits inserted directly into the document.
• Your firm uses standardized playbooks that the AI can reference automatically.
• Your entire team is on Windows with Word licenses and IT can handle add-in deployment.
• Budget allows per-seat pricing (typically $99+/seat/month).

When to Choose a Web-Based Tool

A web-based tool makes sense if:

• You receive contracts in multiple formats — PDF scans from clients, DOCX from opposing counsel, pasted text from emails.
• You work across different devices — desktop at the office, laptop at home, tablet in court.
• You don't use Microsoft Word — or use it occasionally. Many solos write in Google Docs, mark up PDFs, or work entirely in browser-based practice management software.
• You want to try before buying — without installing anything or talking to a sales rep.
• You review contracts for clients who send PDFs, and converting to DOCX is extra friction you don't need.
• You want predictable, per-contract or per-month pricing without per-seat multipliers.

The Hybrid Option: Using Both

Some attorneys use both tools in parallel — a Word plugin for in-depth drafting and a web-based tool for quick intake reviews, client-sent PDFs, and preliminary risk assessment. The web-based tool catches the obvious issues in seconds; the Word plugin handles detailed redlining for contracts that need edits.

This approach works well when the tools address different parts of the workflow. For example, you might use ContractPeer's free contract check for initial risk screening — no signup, no install — then move to a drafting tool for contracts that need your direct edits.

Cost Comparison: Real Numbers

Scenario	Word Plugin (per seat)	Web-Based
Solo attorney, 10 contracts/mo	$99/mo	$49/mo
3-attorney firm, 30 contracts/mo	$297/mo	$99/mo (single account handles all uploads)
5-attorney firm, 50 contracts/mo	$495/mo	$199/mo
Quick one-off review (no subscription)	Not available (subscription only)	Free with limited preview

Web-based platforms scale differently because pricing is tied to contract volume, not headcount. A firm of five reviewing 200 contracts total pays the same as a solo reviewing 200.

Security Considerations

Both approaches face similar security questions: Where is your contract data processed? Who has access? How is it encrypted?

The difference is deployment model:

• Word plugins process contract text through the provider's cloud APIs (the add-in sends the document text to the provider's servers for AI analysis). The document stays on your machine, but its contents transit through the provider's infrastructure.
• Web-based tools receive the uploaded contract, process it server-side, and return results. The contract text is processed and not stored permanently by reputable providers.

In practice, both models send contract text to the provider's AI infrastructure. The key question is what happens to that data after analysis: Is it used for training? Is it stored long-term? Are you notified of sub-processors? A reputable provider in either category should answer these questions clearly in their privacy policy.

Making the Decision: A Simple Framework

1. Assess your input formats. If 80%+ of contracts arrive as .docx files you'd open in Word anyway, a plugin is worth considering. If they arrive as PDFs, emails, or varied formats, a web-based tool handles them more directly.
2. Count your devices. Do you work on one Windows machine, or across a laptop, home computer, and phone? Web-based tools travel with you.
3. Count your people. A 5-attorney firm pays 5× the per-seat price for Word plugins. Web-based tools charge by volume, not people.
4. Try before you buy. The best way to evaluate is to run a real contract through each approach. Paste a contract into ContractPeer's free tool — no account needed — and see the output in seconds.
5. Revisit in 6 months. Your workflow changes. The tool that fits today may not fit in six months. Favor approaches that let you switch without data migration or retraining costs.

Frequently Asked Questions

Can I use a web-based tool alongside Microsoft Word?

Yes. Web-based tools are complementary to Word, not replacements. Use the web tool for quick intake reviews and risk identification, then open the contract in Word for edits based on the analysis.

Do web-based tools support redlining?

Some do (ContractPeer's Professional and Firm plans include redlined edit suggestions). The difference is that web-based tools show suggested edits in the analysis report rather than inserting them directly into your Word document.

Is a web-based tool as secure as a Word plugin?

Security depends on the provider, not the architecture. Both approaches send contract text to cloud APIs for AI analysis. What matters is the provider's data handling — encryption, retention policy, training usage, and compliance certifications.

What if I need to review a contract on my phone?

Web-based tools work in any browser. Upload from your phone's file system, cloud storage, or email attachment. Word plugins require a desktop with Word installed.

Which is better for a solo attorney?

For most solo attorneys, a web-based tool offers better value: lower cost ($49/mo vs $99+/mo), no installation, works with any contract format, and no per-seat pricing. The exception is if you do all contract work inside Word and need in-document redlining.