Client loginBook a call
Build
Custom Software DevelopmentSystems built to your process
Web Application DevelopmentReact, Next.js, Rails, Django
Mobile App DevelopmentiOS, Android, React Native
App DevelopmentWeb and mobile apps, end to end
SaaS Product DevelopmentMulti-tenant from day one
MVP DevelopmentFirst release in 6–10 weeks
Enterprise SoftwareSSO, audit trails, scale
Connect & operate
API Development & IntegrationREST, GraphQL, webhooks
Cloud & DevOps EngineeringAWS, GCP, Azure, Terraform
QA & Software TestingAutomated suites, load, E2E
Legacy ModernizationStrangler-fig migrations
Cybersecurity EngineeringHardening and remediation
Data EngineeringPipelines, warehouses, reporting
Design & teams
UI/UX DesignInterfaces people finish tasks in
Prototyping & DiscoveryScope before you spend
Staff AugmentationSenior engineers on your team
Dedicated Dev TeamsA full pod, one contract
White-Label DevelopmentEngineering under your brand
Technology ArchitectureDecide once, correctly
Project ManagementDelivery you can audit
Start hereScope a build in one callBring a spec, a wireframe, or a paragraph. You leave with an architecture, a timeline, and a number.Book a scoping call
All software development services →How we price work →Talk to an engineer →
AI software
AI Application DevelopmentFull-stack AI products
AI Agent DevelopmentMulti-step autonomous agents
AI SaaS DevelopmentMulti-tenant AI products
Workflow AutomationReplace manual ops
Custom LLM AppsBranded internal assistants
LLM & data systems
Private LLM DevelopmentSelf-hosted Llama, Mistral, Qwen
RAG DevelopmentCited answers over your docs
MCP & WebMCPMake your systems agent-callable
Vector Database Setuppgvector, Pinecone, Qdrant
Document IntelligenceOCR and extraction pipelines
Vibe coding
AI-Assisted BuildsFast, with senior review
Rapid PrototypingClickable in days
Concept to CodeIdea to working software
Code Review & CleanupMake AI output shippable
Fractional AI TeamOngoing build capacity
Ready to ship?Put AI where the work isAgents, RAG, and private LLMs wired into the systems your team already uses — not a chatbot bolted to a homepage.Discuss an AI project
AI development services →AI readiness checklist →AI vs. traditional development →
Domain firstWe learn your workflow before we model itRegulated, operational, or high-volume — the constraints belong in the schema, not in a training doc.Talk about your domain
Selected workSoftware we own and operateMost agencies show screenshots. We run the products — the same stack, uptime, and on-call we hand to clients.View the portfolio
Plan smarterEstimate before you commitCost ranges, scope templates, and the questions we ask in discovery — free, no form.Open the cost calculator
Real conversationsTalk with a technical leadNo SDR, no discovery gauntlet. The person on the call is the one who scopes the build.Book a call
Open-Source DevOps · maester365

maester

Maester is an open-source PowerShell framework for automated testing and monitoring of Microsoft 365 security configurations. It provides a suite of tests, customizable policies, and CI/CD integration to help organizations enforce security baselines across Entra, Exchange Online, and other M365 workloads.

Talk to DEV.coDiscuss Implementation
Source: GitHub — github.com/maester365/maester
957
GitHub stars
259
Forks
HTML
Primary language
MIT
License (OSI-approved)

Key facts

Objective fields from the source. Values we can't verify are shown as “Unknown” rather than guessed.

FieldValue
Repositorymaester365/maester
Ownermaester365
Primary languageHTML
LicenseMIT — OSI-approved
Stars957
Forks259
Open issues42
Latest release2.1.0 (2026-05-02)
Last updated2026-07-08
Sourcehttps://github.com/maester365/maester

What maester is

A Pester-based PowerShell module distributed via PSGallery that connects to Microsoft Graph and M365 services to validate security posture through declarative tests. Supports national cloud environments (Global, China, USGov, USGovDOD) and integrates with GitHub Actions, Azure DevOps, and GitLab pipelines; results exportable as CSV, Excel, HTML, JSON, or Markdown.

Quickstart

Get the maester source

Clone the repository and explore it locally.

terminalbash
git clone https://github.com/maester365/maester.gitcd maester# follow the project's README for install & configuration

Need it deployed, integrated, or customized instead? DEV.co ships production installs.

Best use cases

Continuous security compliance monitoring

Run Maester in scheduled CI/CD pipelines to detect configuration drift and enforce security baselines across M365 tenants without manual audits.

Multi-tenant security baseline enforcement

Organizations managing multiple M365 tenants can use Maester to apply consistent security tests and generate standardized compliance reports for governance and audit purposes.

Rapid security assessment and remediation

Security teams can use Maester's pre-built test suite to quickly assess current M365 configuration posture and identify misconfigurations for remediation workflows.

Implementation considerations

  • Requires valid Microsoft Graph API permissions and M365 credentials; plan for interactive or service principal authentication in CI/CD pipelines.
  • Pester v5.x is a hard dependency; ensure PowerShell version compatibility (PS 7.x recommended for cross-platform) before rollout.
  • Known issue with ExchangeOnlineManagement module v3.9.2; pin to earlier versions to avoid connection errors.
  • Tests are installed to local user home directory (~); plan directory structure and version control strategy for test customization and updates.
  • Notification integrations (Teams, Slack, email) require pre-configured webhooks or credentials; secure storage of secrets in CI/CD pipelines is mandatory.

When to avoid it — and what to weigh

  • Minimal PowerShell expertise in team — Maester requires PowerShell knowledge to install, customize tests, and troubleshoot integrations. Teams without PS proficiency may face adoption friction.
  • Need for non-M365 security posture management — Maester is M365-specific (Entra, Exchange Online, Teams, SharePoint); it does not assess on-premises AD, AWS, Azure compute, or other cloud security configurations.
  • Requirement for centralized, multi-cloud SIEM integration — Maester exports results in standard formats but has no built-in connectors to major SIEM platforms (Splunk, Datadog, etc.); custom integration scripts are required.
  • Absence of managed service or commercial support — This is community-driven open source with no official SLA, paid support tier, or vendor SaaS option. Critical production use requires internal support capability.

License & commercial use

Licensed under MIT (OSI-approved, permissive). MIT permits use, modification, and distribution for any purpose, including commercial, with no warranty and minimal obligations (retain license notice).

MIT license permits commercial use without restriction. However, there is no vendor SLA, paid support, or warranty. Organizations using Maester in production must assume full operational responsibility and should maintain internal or contracted expertise to handle incidents, custom test development, and module maintenance.

DEV.co evaluation signals

Editorial assessment — not user reviews. Directional, with an explicit confidence level.

SignalAssessment
MaintenanceActive
DocumentationAdequate
License clarityClear
Deployment complexityModerate
DEV.co fitGood
Assessment confidenceHigh
Security considerations

Maester itself assesses M365 security configuration; it does not claim to be hardened against supply-chain attacks, malicious PowerShell modules, or API token theft. Deployment considerations: (1) Authenticate via managed identity or service principal with minimal permissions; (2) store credentials securely in CI/CD secret managers; (3) audit PowerShell execution policies and script sourcing; (4) validate module integrity via PSGallery hash checks. No security audit details, penetration test results, or vulnerability disclosure process are provided.

Alternatives to consider

Microsoft Defender for Cloud

Native M365 compliance and security assessment; tight integration with Azure AD and workloads. Trade-off: less test customization, recurring licensing cost.

CIS Microsoft 365 Foundations Benchmark (manual audit or vendor tool)

Industry-standard security baseline for M365. Trade-off: requires manual implementation or third-party SaaS tool adoption; no turnkey automation.

Cloud Security Alliance M365 SecureScore integrations

Native M365 SecureScore dashboard provides continuous monitoring. Trade-off: limited test customization; Microsoft-controlled update cadence.

Software development agency

Build on maester with DEV.co software developers

Deploy Maester to continuously monitor and enforce Microsoft 365 security baselines. Free, open-source, and ready for GitHub Actions, Azure DevOps, and GitLab pipelines.

Talk to DEV.co

Related open-source tools

Surfaced by semantic similarity across the DEV.co open-source index.

maelstrommaelstrommy-arsenal-of-aws-security-tools

Related on DEV.co

Explore the category and the services that help you build with it.

Open-Source DevOpsDevOpsEnterprise SoftwareCloud DeploymentTalk to DEV.co

maester FAQ

Can I run Maester in Azure DevOps or GitLab?
Yes, both are supported via CI/CD integration. GitHub Actions is the primary platform with native artifact and summary features; Azure DevOps and GitLab require custom script wrappers for equivalent functionality.
What happens if a test fails? Does Maester auto-remediate?
No. Maester is a test framework and report generator; it does not auto-remediate. Remediation requires manual action or custom PowerShell scripts that integrate with Maester results.
Does Maester support on-premises Active Directory or hybrid scenarios?
No. Maester is M365-only (cloud). On-premises AD security assessment requires separate tools. Hybrid Entra scenarios are partially covered via Entra configuration tests.
Is there commercial support or a managed SaaS version?
No. Maester is community-driven open source. Support comes from the community, GitHub issues, and the maester.dev documentation. Production use requires internal or contracted expertise.

Custom software development services

DEV.co pairs senior engineers with teams adopting tools like maester. Our software development services span open-source devops architecture, implementation, and the AI development services that increasingly sit alongside them.

Automate Your M365 Security Testing

Deploy Maester to continuously monitor and enforce Microsoft 365 security baselines. Free, open-source, and ready for GitHub Actions, Azure DevOps, and GitLab pipelines.

Talk to DEV.coSchedule a Consultation