Are all Sentinel free tools really free?

Yes. All ten free tools are free with daily rate limits for anonymous users and higher limits for signed-in users. No credit card required.

Do I need to sign up to use the free tools?

No sign-up is required for basic use, but creating a free account gives you higher daily limits and history of past lookups.

Where does the data come from?

Each tool aggregates data from public sources such as Google Suggest, public DNS-over-HTTPS resolvers, RDAP/WHOIS, Certificate Transparency logs, and Lighthouse. Source attributions are shown on each tool page.

Can I access these tools through an API?

Yes — paid customers get programmatic access to most free tools through the documented JSON API.

How are anonymous rate limits enforced?

We use a per-IP token bucket. Sign in for higher daily limits if you need more than the anonymous quota.

Free SEO Tools — Sentinel SERP

Free SEO Tools — no credit card required

A collection of free tools for SEO, performance, and site validation. Run a few checks anonymously, or sign up free (no payment info ever) to unlock higher daily limits.

100% Free No Payment Method Needed Instant Results Signup Optional

You don't need to add any payment method to sign up. Free accounts unlock higher daily limits on every tool — zero charge, ever. We'll only ask for an email and a password.

Free SEO Tools — no credit card required

Keyword Ideas Generator

On-Page SEO Analyzer

PageSpeed & Core Web Vitals

Domain Authority Checker

Site Validator (robots, sitemap, SSL, headers)

DNS Lookup & Records Checker

WHOIS Lookup

DNS Propagation Checker

DNS History Checker

SERP Checker