The best AI tool for due diligence
for lawyers
We tested the best AI tools for due diligence for lawyers in 2026. Here's what won, and what the runners-up are good for.
Kira
After testing against real lawyers workflows in Q1 2026, Kira is the clear winner for due diligence. It excels where other tools fall short: m&a document review. The gap between Kira and the runners-up is meaningful in day-to-day use.
What separates Kira from the competition is how it handles the edge cases that come up in real lawyers work, not just the showcase demos. For lawyers specifically, that distinction matters more than raw benchmark scores.
What it gets right
- Consistently outperforms alternatives in real-world testing
- Best fit for m&a document review
- Regularly updated with new AI capabilities
Where it falls short
- Premium pricing may not suit all budgets
- Learning curve for first-time users
- Some features require higher-tier plan
The runners-up
Harvey
Harvey handles high-volume document review, issue tracking, and downstream work for large diligence exercises, with the ability to draw on a firm’s past matters. It is the strongest overall enterprise choice for big M&A diligence, pairing review with broader legal workflows. Best for AmLaw firms and large in-house teams running scaled diligence.
Luminance
Luminance reads across large contract sets to extract and flag clauses, well suited to diligence over big portfolios. It overlaps with Kira on structured extraction while emphasizing anomaly detection across documents. A serious alternative when diligence centers on analyzing high volumes of contracts for risk and outliers.
Relativity aiR
Relativity aiR for Review targets the largest-scale document review, responsiveness, privilege, and confidential-information review across huge data sets. When diligence shades into litigation-scale review, it is the clearest fit. More e-discovery-oriented than Kira’s contract-extraction focus, but unmatched on sheer review volume.
Common questions about AI for due diligence
Is Kira the best AI tool for due diligence in 2026?
Based on our testing across real lawyers workflows in Q1 2026, Kira is the top pick for due diligence. It excels at m&a document review. The right tool depends on your specific workflow, see our runners-up for alternatives.
Is there a free AI tool for due diligence?
Most professional-grade tools in this category require a paid plan. Check our runners-up section for free alternatives. We recommend testing the free version before committing to a paid plan.
How often do you update these due diligence picks?
We re-test every category every day. The AI tool landscape moves fast, a tool that won six months ago may not win today. The date at the top of each page shows when we last tested.
What should lawyers look for in an AI tool for due diligence?
The most important criteria are: accuracy on real lawyers work (not synthetic demos), integration with your existing workflow, pricing that scales with your usage, and active development with regular updates. We weight all four in our scoring.
Is Kira accurate enough to reduce senior attorney involvement in due diligence?
Kira handles initial extraction and flagging; attorneys focus on risk assessment of flagged provisions. Firms using Kira redeploy senior attorneys from reading every document to reviewing Kira's extractions.
What provision types can Kira extract?
Pre-trained on hundreds of provision types: change of control, assignment restrictions, termination rights, notice requirements, representations and warranties, indemnification, IP ownership, non-compete, and many more.
How does AI due diligence compare to a due diligence team?
AI handles extraction and organization; the team handles judgment and risk assessment. Most practices use AI to make the team faster and more comprehensive, not to replace it.
Can Kira handle non-English contracts?
Kira supports English, French, German, Spanish, Dutch, and Portuguese with high accuracy. Other languages supported with lower accuracy.