How can I tell if an SEO company is using black hat techniques?
By checking the work yourself in the places it leaves traces: the links pointing to your site, the pages added to it, what Google sees when it loads those pages, and how the company answers when you ask where its results come from. Black hat techniques are those that break Google’s spam policies, and the policies describe them concretely enough to check. You do not need technical skill for most of the checks; you need access to your own Search Console and a willingness to ask specific questions.
The links pointing to your site
Search Console’s Links report shows which sites link to you and the text used in those links. Its “Top linking text” view lets you “See which link text is used in backlinks to your site.” Two patterns deserve a question. One is a sudden wave of links from sites unrelated to your business. The other is link text that repeats your target keyword exactly, again and again, across sites that have no other connection to you.
Compare what you find with the link spam examples in the spam policies, which include “Excessive link exchanges”, alongside links from low-quality directories and bookmark sites, buying links, and creating them with automated programs. Then ask the company to name the sites its links came from and how each was earned. A company doing legitimate outreach can tell you; a vague answer about “link building” with no sites named is a reason to look closer.
What Google sees on your pages
Cloaking means showing search engines one version of a page and visitors another, and hidden text is content placed for search engines that visitors cannot easily see. The spam policies give examples of hidden text, among them “Using white text on a white background” and “Using CSS to position text off-screen”. To check, use the URL Inspection tool in Search Console, which, according to Google’s URL Inspection help, lets you “See a screenshot of how the Google-InspectionTool sees the page.” Compare that with what you see in your own browser. A page that looks different to Google, or code that contains text you never see, needs an explanation.
Not all hidden content is a problem: the policies state that design elements such as accordions, tabs, and sliders that show and hide content for users do not violate them.
The pages added to your site
Look at what the company has published. A batch of new pages that say nearly the same thing, pages that differ only by a city name or a keyword, or text that repeats a phrase in almost every sentence are signs of the tactics the spam policies describe as doorways, scaled content abuse, and keyword stuffing. Ask who wrote each page, who reviewed it, and what it is meant to do for a reader.
How the company answers
Watch for promises the company cannot keep, such as guaranteed first-page rankings or a fixed position by a fixed date, and for any reluctance to give you full access to your own Analytics and Search Console. Rankings that jump sharply and then fall are worth a question too: they can follow an aggressive tactic being caught, though they can have other causes, so ask what changed before drawing a conclusion.
If several of these signs appear together, ask for a written account of the company’s methods, including the sites its links came from and the pages it created, and consider an independent review of the site before more work is done.