21 free tools · no sign-up · runs in your browser
Practical security tooling. Pick your stack.
Free, browser-based security tools and no-fluff guides — built by a working engineer, grouped by discipline. No accounts, no paywalls.
Describe it in your own words, or pick a common job. What you type stays in your browser.
Best matches for “our emails go to spam”
Browse all 21 toolsHow the tools handle your data
Try it here
Could someone send email pretending to be you?
Pick a sample domain to see how the , and checker reads a domain's email records and explains what they mean.
Every tool page opens with a worked example like this, so you can see what a result looks like before you enter your own.
monitoring.example
Partly protected
Mail is signed, but receivers are told to deliver mail that fails the checks. Anyone can still send mail that looks like it's from this domain.
- SPFSoft fail
- DKIMSigning
- DMARCMonitoring only
All tools
Every tool, one page.
Each tool says what it's for in everyday words first. Dotted terms explain themselves when you hover over or tap them.
21 tools
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ISO 27001 Control Reference
Look up any ISO 27001 control and see what evidence an auditor will ask for.
Search all 93 ISO 27001:2022 and 114 ISO 27001:2013 controls with audit evidence and 2013 ↔ 2022 mapping.
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SOC 2 Criteria Reference
Understand each SOC 2 requirement and what proof you need to show.
Search all 61 SOC 2 with audit evidence and ISO 27001 mapping.
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NIST CSF 2.0 Reference
Browse the NIST Cybersecurity Framework with examples of the evidence for each part.
Search all 106 NIST CSF 2.0 subcategories with evidence examples and ISO 27001 mapping.
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Control Mapper + Gap Assessment
See where ISO 27001, NIST CSF and SOC 2 overlap, then score how mature your controls are.
Crosswalk ISO 27001:2022, NIST CSF 2.0 and SOC 2, then run a maturity gap assessment.
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Risk Register + Matrix Generator
List your risks, score them by likelihood and impact, and get a heatmap for the board.
ISO 27005 / NIST SP 800-30 aligned risk register with likelihood × impact scoring and a heatmap.
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NetSegmenter CIDR / Subnet Calculator
Work out IP ranges and split a network into subnets without doing the maths by hand.
Subnet, supernet and plan address space: maths, splits and segmentation planning.
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DNS Toolkit Reverse, Records & Propagation
Check what a domain's DNS records say, and whether a change has reached the whole internet.
Reverse () lookups with data, forward records, and a live global DNS propagation map.
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SPF / DKIM / DMARC Checker
Find out why your email lands in spam, or how easy it is for someone to send mail pretending to be you.
Validate email authentication — parse , and and flag misconfigurations.
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ScopeForge DNS & DHCP Planner
Plan which devices get which addresses before you build or move a network.
Plan scopes, reservations and DNS zones for a network build or migration.
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AppLocker Studio
Control which apps are allowed to run on company Windows PCs, and push the rules through Intune.
Read, build and beautify Windows policy XML and generate .
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Windows Event ID Lookup
Find out what a Windows security log entry means and whether it needs attention.
Look up Windows Security event IDs with meaning, fields and detection notes for triage.
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KQL Query Builder
Build searches for Microsoft Sentinel and Defender without memorising the query language.
Build Microsoft Sentinel / Defender hunting queries from guided building blocks.
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RegEx Lab
Build and test text-matching patterns, with ready-made patterns for security work.
Build and test regular expressions against sample data with a security pattern library.
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TokenDecoder JWT
Read what's inside a sign-in token: who it's for, what it allows and when it expires.
Decode and inspect and tokens — header, claims and signature — client-side.
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AuthMethods Readiness Analyzer
See how many of your users are ready for MFA or passkeys, from an Entra export.
Score / readiness from an authentication-methods registration export.
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Conditional Access Analyzer & Designer
Check your Microsoft 365 sign-in rules against Microsoft's recommendations, then design new ones.
Review against Microsoft templates, then design policies as Graph JSON or PowerShell.
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SquatWatch Typosquat Scanner
Find look-alike domains that could be used to impersonate your brand.
Generate and check look-alike / domains for brand-abuse and phishing prep.
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NetRecon IP / Domain / ASN
Find out who owns an IP address or domain, and what network it sits on.
Pull IP, domain and intelligence for external recon and mapping.
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Email Header Analyzer
Paste a suspicious email's headers to see where it really came from.
Parse raw email headers for SOC-grade sender, routing and authentication intelligence.
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TenantRecon Tenant Attack Surface
See which Microsoft 365 and cloud services can be seen from outside for a domain.
Map the SaaS and cloud tenant attack surface for a domain — Microsoft 365 and beyond.
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Subdomain Recon CT Discovery & Takeover
List a domain's subdomains and spot forgotten ones someone could take over.
Find subdomains in logs, then scan them for dangling-record takeover risk.
No tools match that. Try a broader word, or .
Guides
Written while doing the work.
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Passkeys by Default and the Retirement of Microsoft SMS and Voice MFA: The Entra Migration Playbook
Microsoft Entra ID is making passkeys the default sign-in experience and retiring Microsoft-provided SMS and voice authentication. Two dates matter: on 1 September 2026 passkeys are auto-enabled for every user still on…
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The Microsoft 365 2026 Deprecation Deadline Tracker
Every material Microsoft 365, Exchange Online and Entra ID deprecation landing in 2026 — EWS, SMTP AUTH basic auth, Identity Protection risk policies, Azure ACS and more — in date order, with what breaks and the one…
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Anatomy of a Device Code Phishing Email: A Real Investigation
A phishing email with no malware, no cloned login page and a clean URL reputation would still have handed an attacker a fully authenticated Microsoft 365 session — without ever seeing the password, and without the…
Questions
Before you paste anything in.
What is TheAdminStack?
TheAdminStack is a free collection of browser-based cybersecurity and infrastructure tools, plus practical guides, built and maintained by a working security engineer. Every tool lives on one page and can be filtered by discipline: Governance Risk & Compliance (GRC), IT Operations, Security Operations (SecOps) and OSINT.
Are the tools really free?
Yes. Every tool on TheAdminStack is free to use with no account, no sign-up and no paywall. They are built for practitioners who just need to get the job done.
Does my data leave my browser?
The tools are privacy-first. Most run entirely client-side, so the data you enter is not stored or sent to a server. Tools that must query an external source (for example DNS or certificate lookups) only send the minimum needed for that lookup.
How are the tools organised?
All tools are listed on the homepage and tagged by discipline. Use the filter to narrow to GRC, IT Operations, SecOps or OSINT — a tool can appear under more than one discipline where it applies (for example, the SPF/DKIM/DMARC checker is both IT Ops and SecOps).
Who builds TheAdminStack?
TheAdminStack is built by a cybersecurity engineer and systems administrator with 10+ years securing enterprise environments. The site also offers practical guides and is available for security consulting.