When litigation, investigations, and regulatory audits move fast, your ability to capture, preserve, search, and supervise modern communications can make or break outcomes. This week we compare three leaders in the space—Onna, Hanzo, and Smarsh—to help law firms and legal departments choose the right platform for eDiscovery, information governance, and communications compliance across Slack, Microsoft Teams, email, and more.
Table of Contents
- Overview of the Tools
- Features & Capabilities Comparison
- Compliance, Security & Risk Management
- Collaboration & Knowledge Sharing
- User Experience & Learning Curve
- Integration with Microsoft 365 and Other Legal Tools
- Pricing & Licensing Models
- Pros & Cons of Each Solution
- Best Fit Scenarios
- Side-by-Side Comparison Table
- Decision-Support Framework
- Verdict
- Conclusion & Next Steps
Overview of the Tools
Onna centralizes unstructured data from cloud apps—such as Slack, Microsoft 365, Google Workspace, and more—into a searchable, normalized repository. Legal teams use it for targeted collections, early case assessment (ECA), and data governance. Onna’s strength is connecting many disparate sources and enabling defensible preservation and export to industry-standard review platforms.
Hanzo specializes in dynamic data capture and defensible preservation for collaboration content (e.g., Slack, Microsoft Teams) and web content. Its focus is on rendering complex, conversational data with context (threads, edits, reactions) and enabling legal hold, investigations, and ECA. Hanzo is often selected by organizations with heavy Slack/Teams usage where message fidelity and context are paramount.
Smarsh is a communications archiving and supervision platform widely used by regulated enterprises. It captures, retains, and supervises electronic communications (email, chat, social, mobile, Teams/Slack connectors, and more) to support regulatory obligations (e.g., SEC, FINRA, FCA) and enterprise discovery. Smarsh is designed for immutability, policy-driven retention, surveillance workflows, and audit-ready evidence.
- Regulatory-first archiving: If you need surveillance and supervision on communications at scale, prioritize Smarsh.
- Dynamic collaboration fidelity: If most risk sits in Slack/Teams with complex context, prioritize Hanzo.
- Cross-repository discovery: If you need broad, multi-source collections and ECA, prioritize Onna.
Features & Capabilities Comparison
Data capture and scope
All three platforms connect to major cloud sources, but their sweet spots differ:
- Onna: Broad integrations across productivity and collaboration apps; strong at centralizing data from multiple systems for ECA and export.
- Hanzo: Deep, defensible capture of dynamic collaboration content (Slack/Teams), preserving context like threads, edits, reactions, and shared files.
- Smarsh: Comprehensive communications capture for regulated compliance, with advanced policy controls, journaling, and supervision across email, IM, social, voice, and collaboration tools.
Legal hold, preservation, and ECA
- Onna: Supports defensible preservation and legal holds across connected sources; culling, search, and export to review tools for ECA.
- Hanzo: Offers legal hold workflow and targeted collections from collaboration platforms; optimized for investigations and preserving conversational context.
- Smarsh: Provides policy-based retention and supervision with defensible preservation for regulatory communications; often serves as the system of record for communications evidence.
Search, review, and export
- Onna: Unified search across connected repositories; filters, metadata, and content previews; exports in industry-standard formats for leading review platforms.
- Hanzo: Conversation-aware search and review for Slack/Teams; preserves channel structure and context; exports that maintain message fidelity for downstream discovery.
- Smarsh: Powerful search across archived communications; supervision queues and workflows for reviewers; exports designed to meet regulatory and discovery needs.
Key differentiator: If your primary evidence resides in Slack/Teams, choose tooling that understands conversational context. Rendered fidelity and provenance can be the difference between admissible, comprehensible evidence and costly rework.
Compliance, Security & Risk Management
For legal teams, the defensibility of capture, preservation, and supervision is as important as the feature list.
- Regulatory posture: Smarsh is commonly deployed to meet communications archiving and supervision requirements in regulated industries (e.g., SEC/FINRA). Hanzo and Onna support defensible collection and preservation for discovery and investigations, and can complement formal compliance archives.
- Retention and immutability: Smarsh emphasizes immutable archives and policy-based retention aligned to regulatory obligations. Hanzo focuses on accurate, defensible capture of dynamic conversations; retention can be managed within the platform and/or paired with compliant storage. Onna supports retention controls and legal holds to preserve data in a defensible manner for discovery workflows.
- Security and attestations: Each vendor provides enterprise security controls (encryption, access controls, auditing). Many organizations look for SOC 2 Type II and similar attestations—confirm current certifications and data residency options during procurement.
- Privacy and data minimization: Ensure capabilities for data subject rights (e.g., GDPR/CCPA) and selective collection. Onna’s targeted collections support minimization; Hanzo’s source-specific scoping reduces overcollection; Smarsh’s policy-driven ingestion and supervision can restrict unnecessary exposure.
Collaboration & Knowledge Sharing
Onna enables cross-repository knowledge discovery that benefits legal, compliance, and knowledge management. Hanzo facilitates collaboration-aware investigations, preserving conversational context that speeds attorney comprehension and reduces misinterpretation. Smarsh supports supervised review workflows, queue assignment, and policy-based escalation for compliance and legal teams working together under defensible processes.
User Experience & Learning Curve
- Onna: Intuitive for legal ops and litigation support teams performing targeted collections and ECA. Familiar search paradigms and clean exports minimize training overhead.
- Hanzo: Purpose-built for collaboration data; reviewers quickly understand conversation context. Some specialized features (threading, reactions, dynamic rendering) require brief onboarding.
- Smarsh: Enterprise-grade supervision and archive workflows. Powerful but denser UI; best fit for compliance teams and larger legal departments with defined review processes.
Integration with Microsoft 365 and Other Legal Tools
All three vendors integrate with Microsoft 365 to varying degrees:
- Microsoft Teams and Exchange/Outlook: Hanzo and Smarsh offer robust communications capture; Onna supports targeted collections and cross-repository search.
- SharePoint/OneDrive: Onna centralizes documents and supports ECA; Smarsh focuses on communications and compliance capture; Hanzo may address collaboration artifacts linked from Teams.
- Purview and eDiscovery: These platforms complement Microsoft Purview. Many legal teams use Purview for in-place M365 governance and pair it with Onna/Hanzo for broader sources or with Smarsh for regulatory archiving and supervision. All three commonly export to industry-standard discovery tools (e.g., Relativity and similar platforms).
Outside Microsoft, Onna, Hanzo, and Smarsh each support Slack, with Hanzo and Smarsh emphasizing live compliance capture and Onna enabling cross-source discovery and ECA. Additional integrations vary—verify your “must-have” sources during vendor evaluation.
Pricing & Licensing Models
Legal technology pricing is typically quote-based. Expect some combination of:
- Per user/seat fees for reviewers, admins, and/or custodians.
- Connector or source fees for platforms like Slack, Teams, Bloomberg, social media, or web content.
- Data volume and storage tiers (ingested GB/TB, archive retention periods).
- Module-based pricing (e.g., legal hold, supervision, analytics, surveillance).
- Enterprise agreements with minimums and multi-year discounts.
As a rule of thumb, Smarsh often skews toward enterprise/regulatory budgets; Hanzo toward collaboration-rich mid-market to enterprise; Onna is flexible for teams prioritizing cross-source collections and ECA. Always model three-year total cost of ownership (TCO) including storage growth, exports, and professional services.
Pros & Cons of Each Solution
Onna
- Pros: Broad connectors; unified search; targeted collections and ECA; strong exports to downstream review; complements Microsoft 365.
- Cons: Not a purpose-built regulatory supervision platform; may require additional tooling for surveillance or immutable archiving requirements.
Hanzo
- Pros: High-fidelity Slack/Teams capture; preserves threads, edits, reactions; solid legal hold and investigation workflows; excellent for context-heavy collaboration data.
- Cons: Narrower beyond collaboration/web content compared to generalist collectors; may need a separate archive for broad regulatory communications compliance.
Smarsh
- Pros: Built for regulated communications; supervision, surveillance, and audit readiness; broad communications capture and policy controls.
- Cons: Heavier implementation; supervision workflows may exceed the needs of smaller firms; discovery exports may still require specialized review tools.
Best Fit Scenarios
- Onna: Law firms and legal departments needing fast, targeted collections and ECA across many cloud sources. Ideal when you want to complement Microsoft 365 and unify data from multiple apps for discovery.
- Hanzo: Organizations where Slack/Teams are primary evidence sources. Ideal for investigations that demand accurate conversational context and defensible capture.
- Smarsh: Regulated enterprises requiring policy-based, immutable communications archiving and supervision at scale. Ideal for financial services and similarly regulated sectors with audit obligations.
Side-by-Side Comparison Table
| Category | Onna | Hanzo | Smarsh |
|---|---|---|---|
| Primary Strength | Cross-source discovery, collections, and ECA | High-fidelity Slack/Teams and web capture | Regulatory communications archiving and supervision |
| Typical Use Cases | Targeted collections, early case assessment, knowledge discovery | Internal investigations, legal hold for collaboration data, contextual review | SEC/FINRA/FCA communications compliance, surveillance, audit response |
| Microsoft 365 Focus | Search/collect across Exchange, SharePoint, OneDrive, Teams | Defensible capture of Teams conversations | Archive and supervise M365 communications at scale |
| Slack Coverage | Discovery-driven collection and export | Deep contextual capture (threads, edits, reactions) | Compliance capture and supervision |
| Legal Hold | Yes, with preservation across sources | Yes, including custodian management for collaboration data | Yes, aligned with policy-based retention and supervision |
| Supervision/Surveillance | Limited; relies on other tools for formal surveillance | Focused on investigations rather than supervision queues | Robust supervision workflows and lexicon/policy controls |
| Export | Industry-standard discovery export formats | Context-preserving exports for review platforms | Compliance-grade exports for audit and discovery |
| Retention & Immutability | Retention controls; complements compliant archives | Retention for captured content; pairs with compliance storage when needed | Immutable, policy-driven archiving designed for regulators |
| Deployment | Cloud (SaaS) | Cloud (SaaS) | Cloud (SaaS), with enterprise deployment options |
| Data Residency | Regional options; verify current availability | Regional options; verify current availability | Regional options and enterprise controls; verify current availability |
| Pricing Model | Quote-based; users/connectors/storage | Quote-based; sources/seats/storage | Quote-based; users/sources/supervision modules/storage |
| Ideal Org Size | Mid-market to enterprise; also fits agile legal teams | Mid-market to enterprise with heavy collaboration usage | Enterprise and highly regulated organizations |
Decision-Support Framework
Use this checklist to align each platform with your legal and compliance objectives:
- Evidence profile
- Are Slack/Teams conversations primary evidence, or do you need broad, multi-repository discovery?
- Do you require immutable, regulator-ready archives and supervision?
- Compliance obligations
- Which regulations apply (e.g., SEC/FINRA/FCA, GDPR/CCPA)?
- Do you need supervision, lexicon policies, or surveillance workflows?
- Microsoft 365 alignment
- How will the platform complement Purview eDiscovery, retention, and DLP?
- What’s the plan for Teams, SharePoint/OneDrive, and Exchange coverage?
- Discovery operations
- What are your ECA, culling, and export requirements for downstream review?
- How often do you conduct targeted collections vs. continuous archiving?
- Security & residency
- What attestations and regional data residency do you require?
- How will you manage encryption keys and access controls?
- TCO & scalability
- Three-year cost with storage growth and professional services?
- Expected increase in data sources, custodians, or supervision scope?
- Implementation & adoption
- How long to onboard priority sources? What training is needed?
- How will you measure time-to-evidence and supervision throughput?
Verdict
Each platform excels in different legal and compliance scenarios:
- Onna – Best for cross-repository discovery and ECA: If you need to quickly collect, preserve, and search across many cloud apps—and complement Microsoft 365—Onna delivers strong value and exports for review platforms.
- Hanzo – Best for Slack/Teams-centric investigations: When matters hinge on dynamic collaboration content, Hanzo’s fidelity (threads, edits, reactions) provides defensible context and efficient attorney review.
- Smarsh – Best for enterprise communications compliance: For regulated industries requiring immutable archiving, supervision, and audit-ready evidence, Smarsh is purpose-built to meet those needs at scale.
Many legal departments adopt a blended strategy: Smarsh as the communications archive and supervision system of record; Hanzo for high-fidelity Slack/Teams investigations; and Onna for cross-source collections and ECA feeding review platforms. Your mix should reflect your evidence profile, regulatory posture, and Microsoft 365 roadmap.
Conclusion & Next Steps
Onna, Hanzo, and Smarsh address distinct but overlapping needs across eDiscovery, collaboration capture, and communications compliance. Map your highest-risk data sources, regulatory obligations, and Microsoft 365 strategy, then pilot with real matters to validate time-to-evidence and reviewer efficiency. The right platform—or combination—reduces risk, controls cost, and speeds outcomes for your clients and stakeholders.
Want expert guidance on improving your legal practice operations with modern tools and strategies? Reach out to A.I. Solutions today for tailored support and training.
