Casero vs Relativity: Which Is Right for Your Firm?

Relativity is an e-discovery platform. Its job is document review at scale: ingesting large data sets, running predictive coding, applying continuous active learning to cull irrelevant documents, and producing a reviewable set for litigation. Its AI feature, aiR, is specifically designed for this workflow. Relativity has over 200 third-party integrations and supports complex custom workflows, which is why large firms with dedicated Relativity administrators find it indispensable (AI Vortex, 2026). It is powerful, but that power comes with a steep learning curve and significant implementation costs.

Casero is an intelligence layer. It connects to your existing email, documents, and case management systems, extracts entities like people, organisations, dates, events, and obligations, and builds a living knowledge graph for every matter. The goal is not document review for litigation production. The goal is making everything your firm already knows findable, reusable, and connected. A lawyer can type a plain English question and get results drawn from all matters, emails, documents, prior cases, and internal precedents.

These tools solve adjacent but distinct problems. If your challenge is reviewing 800,000 documents for a single litigation, Relativity is built for that. If your challenge is that your lawyers cannot find the work the firm already did on a similar matter three years ago, Casero is built for that.

Relativity's depth is real. For large-scale document review, it remains the industry standard. Predictive coding, technology-assisted review, and continuous active learning are genuinely useful for cutting review time on massive data sets. The 200-plus app ecosystem means you can bolt in specialist tools for whatever your workflow requires.

The limits are equally real. Licensing costs for large-scale implementations are estimated between $125,000 and $250,000 annually, before implementation, training, and ongoing specialist support (AI Vortex, 2026). Firms without a dedicated Relativity administrator routinely struggle. The platform's complexity is not incidental; it reflects the genuine complexity of enterprise e-discovery. Smaller firms or teams without established review workflows often find they are paying for infrastructure they cannot fully operate.

Relativity also does not solve the institutional knowledge problem. It can tell you which documents are relevant to a privilege review. It cannot tell you that your partner in Manchester handled a nearly identical employment dispute two years ago and already built a strategy you could reuse. That is a different layer entirely. See our article on law firm institutional knowledge loss for more on why that gap matters.

Casero's knowledge graph does something Relativity is not designed to do: it maps relationships across your entire matter history. Every person, organisation, date, obligation, and event extracted from ingested documents gets connected to every related node, and every fact traces back to its exact source document. Click any node and you see the original passage. No black boxes.

The Similar Cases Matching feature is a concrete example of this difference. Casero automatically surfaces past matters based on legislation, factual circumstances, and case classification, with multi-dimensional scoring that shows why each case matched. That is institutional memory made queryable. Relativity does not offer this because it is not trying to; its scope ends at the matter level.

Casero's semantic search lets lawyers ask questions in plain English across all matters, emails, documents, prior cases, and legislation simultaneously. Not keyword filters. Not Boolean operators. Plain English. For a fee earner trying to find a specific indemnity clause from a deal done eighteen months ago, this is the difference between thirty seconds and thirty minutes.

Casero also integrates with Google Workspace, Microsoft Outlook, Microsoft SharePoint, Clio, and custom vaults, and syncs live. Changes in connected systems are mirrored instantly, with no manual uploads. For legal matter management teams running multiple active matters simultaneously, that live sync removes a category of administrative work entirely.

Relativity's cost structure reflects its enterprise positioning. Industry estimates put annual licensing at $125,000 to over $250,000 for large implementations, plus implementation costs, specialist staffing, and ongoing training (NSerio, 2026). For firms with high-volume litigation review needs, that cost can justify itself quickly. For everyone else, it is a significant commitment.

Casero offers a Pilot tier where partners receive full Professional-tier access during the pilot period with no commitment required. The Professional tier pricing is negotiated during onboarding rather than published publicly, but Casero's on-site ROI calculator estimates approximately £10,620 per year for 15 lawyers. Enterprise pricing is custom. The access cost gap between these two platforms is not marginal.

The relevant question is not which tool is cheaper in absolute terms. It is whether you need e-discovery infrastructure or a case intelligence layer. If your firm runs high-volume document review for complex litigation, Relativity's costs are an entry fee to a capability you genuinely need. If your firm's primary pain is scattered knowledge, lost institutional memory, and lawyers spending hours hunting for work the firm already did, paying Relativity rates solves the wrong problem entirely.

Relativity's security posture is enterprise-grade and long-established. RelativityOne holds SOC 2 certification, and its market position in regulated industries reflects years of compliance investment.

Casero's approach is strict by design, even in its current certification stage. Client data is never used to train AI models. Data is encrypted at rest and in transit and never leaves your jurisdiction. Tenant data isolation means strict client-matter segregation at the tenant level. Ethical wall adherence is built in: if a lawyer cannot access a document in the connected DMS, they cannot query it in Casero either. Every action is recorded in a full audit trail, covering who accessed what, when, and based on which document.

The honest caveat: Casero's SOC 2 and ISO certifications are on the roadmap but not yet obtained. The security whitepaper is available on request during pilot onboarding, not as a public download. For firms with strict third-party vendor requirements, that matters. For firms doing a pilot to evaluate the platform, the architecture itself (tenant isolation, no training on client data, and jurisdiction-locked storage) is worth reviewing directly with the Casero team. See our legal AI data privacy guide for the questions every firm should be asking any vendor.

Choose Relativity if your firm handles high-volume litigation requiring structured document review, predictive coding, and privilege workflows at scale. Large law firms and corporations with dedicated e-discovery teams, established Relativity administrators, and complex review pipelines get genuine value from the platform's depth (AI Vortex, 2026). The cost is high, but the capability matches it.

Choose Casero if your firm's problem is knowledge, not review volume. If lawyers are duplicating research that already exists in the firm, if onboarding new associates means starting from zero on matters the firm has handled before, if finding a relevant precedent takes longer than writing a new one, those are intelligence layer problems. Relativity does not fix them. Casero is built for them.

Many firms will find these tools are not competing at all. A litigation practice running Relativity for e-discovery can run Casero as the intelligence layer sitting above it, connecting matter knowledge, surfacing prior work, and making the firm's collective experience queryable. The AI knowledge layer guide for law firms covers how that architecture works in practice.