Microsoft 365 Tools

A growing collection of free, browser-based Microsoft 365 tools, including a tenant name checker and a license SKU and GUID lookup, built from real admin work.

Simplifying Everyday Microsoft 365 Tasks

Microsoft 365 administrators and users often need quick answers to questions that would normally require searching through documentation, opening an admin center, or running PowerShell. This page brings together a growing collection of free, browser-based tools designed to make those everyday tasks faster and easier. Built from real-world administrative experience, each tool provides clear information without requiring access to your Microsoft 365 tenant.

Microsoft 365 Tenant Name Check

Every Microsoft 365 tenant is assigned a permanent, globally unique yourname.onmicrosoft.com address, and that name can only exist once across the entire Microsoft 365 ecosystem. This tool checks a proposed tenant name against Microsoft's public sign-in metadata and reports, in about a second, whether the name is still available or already in use.

It is useful when provisioning a new Microsoft 365 or Office 365 tenant, planning a tenant rename, or confirming whether an organization already has an Entra ID tenant registered under a given name.

Check a tenant name →

M365 License SKU Lookup

Microsoft identifies the same license three different ways: a friendly name in the admin center, such as Microsoft 365 E5, a string ID in PowerShell and Graph output, such as SPE_E5, and a GUID. Outside the admin center, matching those identifiers to a plain English product name is not always simple.

This tool translates between friendly names, string IDs, and GUIDs for both license SKUs and the individual service plans inside them, covering Microsoft's full published licensing reference. It also supports bulk lookups, useful for translating exports, scripts, or tenant audit reports in one pass.

Look up a license SKU →

M365 Graph Permissions Lookup

App manifests, consent grants, and access tokens identify Microsoft Graph permissions by GUID or by terse scope names such as Mail.Read. This tool translates those identifiers into what they actually allow, covering Microsoft's full published reference of delegated scopes, application permissions, and Entra built-in roles.

It distinguishes delegated permissions, which act on behalf of a signed-in user, from application permissions, which let an app act on its own with no user present, and flags which ones require admin consent. It also decodes the wids claim from a token to show which Entra directory roles a user holds.

Look up a Graph permission →

Microsoft 365 Email Header Analyzer

Raw email headers record the full delivery path of a message, including every mail server that handled it, how long each hop took, and the SPF, DKIM, and DMARC results returned along the way. That information is accurate but nearly unreadable in its raw form. This tool parses pasted headers and organizes them into a summary, an authentication breakdown, and a hop-by-hop delivery timeline.

It is useful for tracing where a delayed message lost time, confirming whether a message actually passed SPF, DKIM, and DMARC, and reviewing the complete parsed header set when the summary is not enough. Everything is parsed locally in the browser, so nothing pasted into it is ever uploaded.

Analyze email headers →

AADSTS Error Code Lookup

Microsoft Entra sign-in and authentication failures return as AADSTS codes, usually buried inside a much longer error message from a sign-in log, an application response, or a PowerShell session. This tool matches those codes, or a full pasted error message, against Microsoft's published error code reference and adds practical fix notes for the ones administrators run into most often.

It also supports keyword search, so a term such as consent, redirect, or MFA surfaces matching error descriptions without knowing the exact code. Everything runs from data embedded in the page, so nothing pasted in, including usernames or app IDs, is sent anywhere.

Look up an AADSTS error →

Why these tools exist

Most Microsoft 365 questions can be answered from documentation. Some can only be answered by checking directly, and the official paths to that answer often require signing in, opening an admin center, or writing a PowerShell script. These tools exist for the moments when a direct answer is all that is needed.

Each one runs entirely in the browser against publicly available data. No tenant is accessed and no input is stored. This list will grow as more of these internal utilities are cleaned up for public use.