Stratum PEO

Stratum PEO is a self-hosted payroll and HR platform for firms administering services for clients. It is best suited to PEOs, ASOs, staffing agencies, and CPA firms that need operational control over their own infrastructure. Its broad workflow coverage is appealing, but buyers should weigh annual tier costs and paid implementation against the work of running it on-premises.

Overview

Stratum brings payroll, employee and client administration, HR workflows, and CRM together for organizations serving multiple client businesses. The platform runs on the customer's infrastructure, making control over deployment a central advantage—and infrastructure ownership a real operational commitment.

Its 16 FastAPI microservices sit behind one API gateway, with Next.js frontends, and modules can be deployed independently. That structure can support a staged or selective rollout; it does not remove the need to operate the underlying environment.

Key features

Payroll and HR operations

The in-house tax engine handles federal, state, and local withholding across all 50 states and D.C., including multi-state allocation and NACHA ACH export. That makes Stratum relevant to payroll operators handling employees across jurisdictions. Onboarding checklists cover employees and clients, with LLM-assisted I-9 extraction and E-Verify; offboarding includes separation notice workflows for 21 states.

Client company portals, payroll and tax administration, benefits enrollment, compliance tools, employee self-service, and HR onboarding cover core service workflows. For client-facing teams, case management adds SLA tracking, escalation rules, AI-assisted triage, and Twilio CTI call logging, while a sales CRM supports sales activity. Native connectors include BambooHR, Greenhouse, Lever, QuickBooks Online, Xero, Slack, Deputy, and Clockify. Migration adapters for ADP, Paychex, Gusto, Workday, Rippling, QuickBooks, and BambooHR may help firms moving from those systems.

Security and compliance

Stratum describes schema-per-tenant PostgreSQL isolation, AES-256/Fernet encryption for PII at rest, bcrypt password hashing, mandatory MFA for privileged roles, SAML 2.0 SSO, and append-only audit logging. Those controls address important security needs for a multi-tenant service operation, but the company says they are SOC 2 CC6-aligned and that a formal certification engagement is planned; buyers who require completed SOC 2 certification should account for that distinction.

Pricing

Stratum has no free plan. Annual tiers vary by service type and volume, with flat prices within each tier reviewed at renewal. Temporary mid-cycle overages do not trigger retroactive billing or a penalty, which reduces the risk of a short-lived volume spike. Individual microservices can be purchased à la carte with custom pricing.

• CPA channel: Starter costs $9,000 a year, billed $9,000 annually, for up to 100 employees administered. Growth costs $12,000 a year, billed $12,000 annually, for 101–500 employees. Established costs $15,000 a year, billed $15,000 annually, for 501–1,000 employees; it is capped and graduates to ASO pricing beyond that range.
• Staffing: Starter costs $11,000 a year, billed $11,000 annually, for up to 100 trailing-12mo placements. Growth costs $14,000 a year, billed $14,000 annually, for 101–500 trailing-12mo placements. Established costs $18,000 a year, billed $18,000 annually, for 501+ trailing-12mo placements.
• ASO: Starter costs $19,000 a year, billed $19,000 annually, for up to 1,000 administered employees. Growth costs $23,000 a year, billed $23,000 annually, for 1,001–2,500. Established costs $27,000 a year, billed $27,000 annually, for 2,501+.
• PEO: Starter costs $25,000 a year, billed $25,000 annually, for up to 1,000 covered employees.

These tiers make the most sense when a firm's service type and volume fit a defined band. Implementation and support cost $150/hr; break-fixes are covered by a 90-day warranty after signed go-live acceptance. That hourly charge matters for buyers budgeting beyond the annual subscription, particularly during rollout.

Platforms

Stratum supports Android, iOS, web, API, and self-hosted deployment. Its on-premises model is the defining platform choice: it suits firms that need to run the system on their own infrastructure, not teams looking for a hosted service that avoids infrastructure responsibility.

Who it's for

PEOs, ASOs, domestic EORs, staffing agencies, and CPA firms running payroll for clients are the intended audience. Stratum is strongest for operators that need client-facing administration and broad payroll and HR workflows in one system, and that can own deployment. It is a weaker fit for small organizations seeking a free entry point, or buyers unwilling to manage on-premises infrastructure and hourly implementation or support.

Pros and cons

• Pro: The tax engine covers all 50 states and D.C., with multi-state allocation and ACH export, useful for payroll operators serving geographically dispersed clients.
• Pro: Independent microservices and a range of native connectors and migration adapters give firms options for rollout and transition.
• Pro: Case management, SLA tracking, escalation rules, and call logging connect service operations with payroll and HR workflows.
• Con: Customers must provide and operate their own infrastructure; this is not a hosted deployment.
• Con: Annual tier fees start at $9,000 a year, and implementation and support are billed at $150/hr.
• Con: SOC 2 controls are described as CC6-aligned, with formal certification engagement planned rather than completed.

Alternatives

Explore the PEO Software category to compare options. Choose Paychex PEO if you want a paid PEO service with customized pricing by consultation and support across Android, iOS, macOS, web, and Windows. PrismHR HCM Benefits Enrollment may be a better fit for buyers prioritizing customizable options that scale as needs change. Consider VensureONE as another paid PEO option. TriNet PEO Technology Platform uses a customized estimate based on company size, industry, geographic footprint, and services needed, making it an alternative for buyers seeking a tailored quote. PEOAdmin is another paid option. PHRBO PEO Software offers a $8 a month package per active worker for 100 or fewer workers, with no feature gates; its billing period is unspecified, so compare terms before choosing it. PRO Software is another paid option with pricing provided by quote request.

Verdict

Stratum PEO is a strong candidate for PEOs, ASOs, staffing agencies, and CPA firms that need client payroll and HR workflows on infrastructure they control. Its breadth, modular architecture, and multi-state tax handling are the case for choosing it. Look elsewhere if you need hosted deployment, completed SOC 2 certification, or a lower-commitment way to start.