Check If Ads.txt Is Readable: Simple 2025 Guide for Publishers to Boost Ad Revenue

How to Check If Your Ads.txt File Is Readable by Demand Partners (Simple Steps for Publishers)

Every successful publisher relies on a clean, visible ads.txt file at the heart of their ad setup. This small text file lets buyers know which partners are allowed to sell your ad space. If it isn't readable, trusted advertisers can't reach you and programmatic earnings can dry up overnight.

When the ads.txt file goes ignored or contains even one mistake, ad buyers back away and fraud risk creeps in. It's not just about ad fraud either; even simple problems (like file location or a typo) can block access from top demand partners, cutting revenue fast.

Checking if your ads.txt file is visible isn't hard. You just need to make sure it's uploaded in the right spot, loads cleanly, and is free of errors. In the next section, we'll walk you through exactly how to do that so you can stay protected and keep your ad earnings strong.

Watch a helpful video on ads.txt readability

Understanding the Purpose of Ads.txt

At first glance, the ads.txt file might look like a basic list of text entries. But behind those lines is a promise to ad buyers, demand partners, and the entire digital ad ecosystem. Ads.txt is how publishers draw a bright line that says, "Only these partners can sell my site’s ad space," helping keep ad transactions honest and revenue protected.

What Is Ads.txt?

Ads.txt stands for "Authorized Digital Sellers." It’s a publicly accessible file you host at the root of your website. Think of it as a trusted guest list for your ad inventory. If a demand partner (like an ad exchange or supply-side platform) doesn't find its name on your ads.txt, it knows it isn’t allowed to sell your ad space.

When you create your ads.txt file, you’re writing down who you’ve allowed to represent your inventory. Demand partners check this list before placing bids to confirm they’re dealing with the real publisher and not an imposter. This simple move helps cut out fraud and misrepresentation.

If you want a deeper dive, you’ll find a thorough explanation in this guide on everything you should be asking about ads.txt.

Why Do Demand Partners Need Access?

Demand partners act as your go-between, connecting your site with advertisers ready to spend real dollars. For them, seeing your ads.txt file is not optional—it’s required. Here’s why:

• Trust: Demand partners want proof that your inventory is genuine.
• Connection: Before sending bids, demand partners need to know they’re buying from someone who’s authorized.
• Compliance: Most large ad buyers refuse to work with sites missing a valid ads.txt file.

When demand partners access your ads.txt, they compare their own records with what you’ve published. If there’s a mismatch, they may stop bidding, cutting off a major source of income. By keeping the file easy to find and up to date, you show every demand partner (big or small) they can trust your ad inventory.

To learn more about how ads.txt works as a shield against fraud, check out this breakdown from IAB Tech Lab.

How Ads.txt Protects Publishers

Without ads.txt, it’s easy for fraudsters to pretend they’re selling your inventory on shady sites, draining real value from your business. Ads.txt helps prevent:

• Domain Spoofing: Prevents scammers from faking your site’s identity in ad marketplaces.
• Revenue Leakage: Blocks unauthorized sellers from collecting revenue that should go to you.

When ad buyers know your ads.txt is accurate, your inventory becomes more attractive. This transparency builds confidence across the whole supply chain.

The IAB’s initiative behind ads.txt was designed to help publishers of all sizes, as highlighted in this helpful FAQ from Microsoft.

Real-World Example

Imagine your site gets reviewed by a top ad network. They comb through your ads.txt and see every authorized partner, clear as day. Your ad opportunities multiply, and advertisers know exactly where their buys are going.

On the other hand, if your ads.txt is missing or incomplete, top-tier partners can’t verify you. Even a small typo can send them away, leaving easy money on the table.

Having an accurate, accessible ads.txt is like putting a lock on your digital front door. You control who comes in and who profits—no guesswork, just clear signals to all your partners.

How to Locate and Access Your Ads.txt File

Knowing where your ads.txt file lives is the first step to making it readable for demand partners. The process is simple, but missing even one piece can cause your ad revenue to drop or stop. Finding the file is like checking your mailbox: it’s right out front, and everyone who needs access should find it with no barriers. Here’s how to pinpoint your ads.txt file and make sure it’s easy to see for any ad buyer.

Find Your Ads.txt File at the Root of Your Domain

The ads.txt file should be in one place only: the root directory of your site. This is the top folder of your domain, the “front porch” of your web property. For example, if your website is example.com, your ads.txt file should be located at:

• https://example.com/ads.txt

If your ads.txt file isn’t at the root, demand partners and ad crawlers won’t see it. They don’t look in subfolders, hidden pages, or alternate URLs. The root directory is the only place that matters for ads.txt. If you are not sure how to upload to your root, you can find a detailed walk-through in this Ads.txt guide from Google AdSense.

For WordPress users, this usually means putting the file in the public_html folder or using ad management plugins. You’ll find a helpful setup tutorial for WordPress in this step-by-step manual.

View the File in a Browser

Making sure your ads.txt file is truly public is as easy as typing it in your browser bar. Anyone—including demand partners—should be able to visit your ads.txt file just like they’d visit your homepage. Here’s how to check:

1. Open a new browser tab.
2. Type your site’s full domain followed by /ads.txt.
3. Press Enter.

You should see plain text (usually a series of lines with partner names and numbers). If you see an error or a blank page, your file may be missing or in the wrong spot.

Quick-Scan Table: How Your Ads.txt File Should Be Accessible

What to Enter	What You Should See	What it Means
yourdomain.com/ads.txt	List of partner entries	File is found and readable
yourdomain.com/subfolder/ads.txt	Error or "file not found"	Wrong location, not accessible

If you want an easy way to double-check if your file is public, try out the tips in this Ads.txt Not Found troubleshooting guide.

Real-World Scenario: What Happens When the File Isn’t at the Root

Imagine a publisher who keeps their ads.txt file buried deep in /files/settings/ads.txt. When programmatic buyers come looking, they can’t see a thing—ads stop showing, and revenue plummets. By moving the file to yourdomain.com/ads.txt, everything works like clockwork. Bids return, trusted partners reconnect, and lost earnings reappear.

It pays to check your file’s location and make sure every demand partner and crawler gets a clear view right from your main website address. With this step done, your next job will be verifying that partners can read it without trouble, every single time.

Checking Readability: Manual and Automated Methods

Making your ads.txt file visible at the right URL is the first step. Next, check if demand partners actually see what you see. Both manual checks and automated tools help confirm that your ads.txt file is accessible, clean, and error-free. This keeps your revenue safe and your partner trust high.

Manual Verification in Your Browser

The fastest way to check if your ads.txt file is readable is to load it just like a demand partner would. Open any web browser and type your full domain, plus /ads.txt, like this:

• https://yourdomain.com/ads.txt

If your setup is correct, your ads.txt file opens instantly as plain text. There should be no password prompts, download dialogs, or render issues. A healthy file will show:

• A plain text list of entries, each on a separate line (no formatting or code)
• Entries look like: adnetwork.com, 12345, DIRECT, f08c47fec0942fa0

• Comments or blank lines get ignored and can be included for notes

• No 404 or “file not found” errors, and no redirects

Spotting bright green flags means demand partners can scan your list too. If you see an error page or the file doesn't load, that’s a sign there’s a technical block or it might not be in the right spot.

Here’s a quick list of what a good ads.txt page looks like:

• Starts loading with text, not a prompt to download
• Matches your latest updates (double-check for typos or missed partners)
• Readable without logging in
• Shows a mix of familiar ad partners, your unique publisher IDs, and designations like DIRECT or RESELLER

If your browser view matches that, you’re in good shape.

Using Third-Party Tools for Validation

Even when your file looks correct, hidden problems can sneak in. Small syntax errors or formatting mistakes can cause partner systems to reject your file. That’s where online validators come in—making it easy to spot and fix problems fast.

Popular third-party tools include:

• ads.txt Guru Validator: Paste your ads.txt URL to run a full check. This tool scans for errors, missing fields, duplicates, and formatting problems its scanners don’t miss. It shows results in seconds, making fixes simple.
• IAB Ads.txt Validator: Used by many pros and platform partners, this review tool helps diagnose “invisible” file issues, like invalid publisher IDs or forgotten variables. See the latest info from IAB Tech Lab for updates on standard checks.

Why use these tools? They catch what the naked eye misses:

• Syntax errors: Missing commas, wrong field order, or illegal characters
• ID mistakes: Wrong length or format for publisher account numbers
• Duplicate entries: Multiple lines for the same partner can cause confusion
• File-type or status errors: Ensures your server returns a real 200 OK response with a text/plain content type

Most validators only need your website’s domain. Just copy and paste your ads.txt URL for a stress-free audit.

Want extra peace of mind? Set a reminder to re-check your file monthly or each time you add a new partner. A quick scan with a trusted validator (like ads.txt Guru) can save you countless headaches and keep every demand partner confident you’re open for business.

Checking both by hand and with an automated tool covers all the bases—keeping your ads.txt truly readable from every angle.

Ensuring Ads.txt File Accuracy and Formatting

Clean formatting and up-to-date ads.txt entries are your safety net against lost revenue and confusion for your ad partners. Mastering the small details in each line is what separates a trusted publisher from one that gets passed over. Let's dig into what every ads.txt entry means, why formatting matters, and how simple slips can turn into major headaches.

Understanding the Required Fields

Each line in your ads.txt file is a handshake with a demand partner. It needs to follow a simple recipe—no missing pieces, no extra words. Every entry should have these core elements, separated by commas:

• Domain Name: The official system domain of your demand partner. For example, google.com for Google AdSense or Google Ad Manager.
• Seller Account ID: This is your unique publisher or seller identification number assigned by the partner. Sometimes it looks like pub-0000000000000000.
• Relationship Type: Write DIRECT if you work directly with the partner, or RESELLER if an intermediary is involved.
• Certification Authority ID (TAGID) (Optional): Some partners add a certification ID, like Google’s f08c47fec0942fa0, for added trust.

Here's an example:

google.com, pub-1234567890123456, DIRECT, f08c47fec0942fa0

A quick review of each field:

Field	Example	What It Means
Domain Name	google.com	Where the ad requests are routed
Seller Account ID	pub-1234567890123456	Your code in the partner's system
Relationship Type	DIRECT	You sell directly (or RESELLER for indirect)
Certification Authority ID	f08c47fec0942fa0 (optional)	Tag to verify trusted sellers

Never skip the first three—demand partners check these when they decide to serve your site. The optional fourth field adds an extra layer if you work with partners who require it. To see best practices for filling each field, check out this Google AdSense ads.txt guide.

Common Formatting Problems to Avoid

Even one misplaced comma or typo can break the chain. Formatting issues creep in fast, but a close look now can save you hours and lost earnings later. Here are problems that trip up most publishers:

• Extra spaces: Blank spaces before or after commas can confuse partner systems.
• Missing commas: Leaving out a comma glues two fields together, which breaks the entry.
• Outdated sellers: Don’t keep partners who no longer sell your inventory. This confuses buyers and makes your list hard to trust.
• Misspelled domains: Writing gooogle.com instead of google.com is easy but stops proper verification.
• Wrong account IDs: Typos or old numbers mean ad partners can’t connect you to your account.
• Wrong relationship tags: Mixing up DIRECT and RESELLER hurts your trust with buyers.
• Duplicate lines: Multiple entries for the same seller can cause errors or uncertainty.

Here’s how to avoid these common mistakes:

• Always copy and paste account IDs and domain names from the official partner portal.
• Use a simple text editor to update your ads.txt. Word processors may add unwanted formatting.
• After any updates, validate your file with tools recommended in the official ads.txt specification.
• Audit your partner list each quarter. Remove inactive, outdated, or unknown sellers from your file.
• Stick to the official structure described by guides like this walkthrough on creating an ads.txt file.
• When in doubt, comment entry changes with # so you know why changes were made—but never place comments at the end of a line.

Keep your lines clean and current. The reward is a file that machines and humans can both trust—a small step that builds big confidence with every demand partner you work with.

Troubleshooting Accessibility: File and Server Issues

A simple typo or technical hiccup can slam the door shut between you and trustworthy ad buyers. Even publishers who follow every ads.txt rule can face stubborn problems with file or server errors. Demand partners won’t hunt for your file—they expect it at the front door, readable without extra steps, and free from glitches on every visit. When these roadblocks pop up, your ad dollars can dry up in silence. Let’s walk through the most common accessibility traps and how to fix them with confidence.

Wrong File Location

If your ads.txt file isn’t exactly at yourdomain.com/ads.txt, demand partners will never find it. Some publishers tuck it into a subfolder, others use typos and swap “adstxt” or “ad.txt.” These small lapses tell buyers and crawlers, “this inventory is off limits.”

Ways to spot and solve mislocation:

• Visit your site at /ads.txt in a browser. If you see your partner list, you’re golden.
• Move your ads.txt out of subfolders like /files/ or /uploads/.
• When using CMS tools or managed hosting, look for “root directory” options, often called public_html.

If your ads.txt still won’t show up after a move, check that your server recognizes and serves it exactly at the root. You’ll find more step-by-step fixes in the Google AdSense support thread for missing ads.txt files.

Server and Permission Errors

Even with a perfectly placed file, locked-down server settings can make you invisible to buyers. If your ads.txt file throws a “403 forbidden,” “401 unauthorized,” or “500 server error,” those are hard stops for demand partners.

Common server pitfalls:

• File permissions are too strict. The web cannot read your file.
• .htaccess or firewall rules block plain text files or non-browser visitors.
• Server responds with the wrong file type or status code.

Best practices to unclog these blocks:

• Make your ads.txt file “publicly readable.” Most hosts call this “644” permission.
• Update your server’s rules to allow plain-text files at the root.
• Check that the file loads as text/plain in your browser’s network inspector.

For troubleshooting, HeaderBidding.co’s guide to fixing ads.txt issues lays out clear steps for common server missteps.

HTTPS Misconfigurations

More buyers and ad tech partners require secure (HTTPS) sites. When your site is served over HTTPS, but your ads.txt file is missing an SSL certificate, loads over HTTP only, or triggers browser warnings, connection breaks can cut off buyers.

Here’s how HTTPS trip-ups show up:

• Visiting https://yourdomain.com/ads.txt gives a warning or error.
• Browsers redirect HTTPS requests to HTTP and vice versa, throwing off crawlers.
• Your ads.txt file exists, but a “mixed content” warning or insecure link blocks it.

To correct HTTPS woes:

• Secure your entire domain with a valid SSL certificate.
• Always upload your ads.txt to the main HTTPS root, not just HTTP.
• Test file access with https://yourdomain.com/ads.txt for a clean read, no warnings, and no forceful redirects.

Sticking to a clean, secure protocol builds trust with every partner and unlocks full eligibility for premium demand.

Outdated Caches

Sometimes you make a fix, but old versions of your ads.txt file still show up. Caching plugins, server-side caching, or stubborn browser memory can trick you into thinking your update “didn’t work.” Demand partners might see yesterday’s file even if you made fresh changes.

Key signs of cache trouble:

• Updates to ads.txt take hours or days to appear.
• Different devices see different file versions.
• Third-party validators report stale or missing entries after a fix.

To flush out old versions:

• Clear browser cache after updating your file.
• Invalidate server-side or CDN caches (like Cloudflare or AWS).
• Wait for your cache provider’s refresh cycle, or force a purge if possible.
• Ask your demand partners or use online tools to confirm the update.

Cache glitches are sneaky, especially on larger or high-traffic sites. For hands-on advice about cache and file update problems, check the suggestions in the Ads.txt troubleshooting steps from Google AdSense.

DNS and Propagation Problems

Moving to a new host or changing your DNS can lead to your ads.txt file disappearing from public view or becoming unreachable worldwide. Domain propagation doesn’t happen in a flash—parts of the world (or parts of your own office) may see old or missing DNS records.

Symptoms tied to DNS issues:

• Your ads.txt file is visible on one device but not another.
• Tools report “file not found” just after a hosting change.
• You see the file on your mobile network but not on your office Wi-Fi.

How to fix DNS-related hurdles:

• Check DNS has fully propagated using free global DNS check tools.
• Be patient; changes can take up to 48 hours to show worldwide.
• Ping your URL from different devices and networks to spot region problems.

For more DNS troubleshooting ideas and a rundown of ads.txt fixes, review this actionable roundup from Mile Tech’s blog on common issues and solutions.

A tiny misstep in any of these areas can keep your ads.txt file hidden. When your “open sign” isn’t in the window, programmatic buyers stay away. Keeping your file easy to find, your server welcoming, and your tech up to date is how you reopen the door and keep ad earnings flowing.

Best Practices for Ongoing Ads.txt Monitoring

Staying on top of your ads.txt file isn’t a one-time chore. It’s an ongoing task, like keeping the oil changed in your car or checking smoke detectors at home. If you forget to check for changes or ignore alerts, even a small slip can leave your revenue exposed. Keeping your ads.txt healthy doesn’t have to be hard, but it does demand a routine and solid teamwork with your demand partners.

Photo by Christina Morillo

Automate File Checks with Monitoring Tools

Manual checks are helpful but easy to skip. To avoid missed updates, use automated tools that scan your ads.txt file at set intervals. These tools can:

• Test if your ads.txt loads quickly and returns a 200 OK status.
• Compare your file’s content to previous versions.
• Alert you to any unauthorized changes, missing lines, or unusual edits.

Trusted platforms and custom scripts can ping your ads.txt every day and email you if they spot trouble. Some even show you which partners were added or removed. Using a quality validator, such as the ads.txt Guru Validator, helps catch errors as soon as they pop up.

Schedule Routine Audits for Accuracy

Set a regular schedule to review and update your ads.txt file—monthly, quarterly, or after bringing on a new partner. These routine audits help you spot old or inactive sellers, check for typos, and stay current with your ad tech needs. Here’s a handy routine you can follow:

1. Compare entries in your ads.txt to your active partner list.
2. Remove outdated sellers and confirm new entries.
3. Check formatting and order with a validator.
4. Document each change using a log or comment in the file.

Regular audits build trust with your partners and keep you ahead of costly mistakes. Many publisher-focused resources, such as this Ads.txt Guide from Setupad, recommend making this part of your monthly workflow.

Work Closely with Demand Partners

Keeping your ads.txt file up to date is a team effort. Demand partners often update their requirements or retire old accounts with little warning. Make it a habit to:

• Ask partners for the most recent ads.txt lines when you sign new agreements.
• Request immediate alerts if your account setup changes or partners spot problems.
• Share your file for review with your partners—most are happy to double-check for errors.

Open communication keeps both sides confident and speeds up problem solving. Some partners provide tools or dashboards to monitor your file's visibility from their side. Take advantage of these resources to avoid surprises.

Embrace Industry Standards and Best Practice Resources

The IAB’s standards and ongoing updates set the bar for the whole industry. Following their guidelines, as highlighted by experts at Sellers.Guide, helps you meet the expectations of all buyers and platforms. Key habits that match industry best practices include:

• Hosting the file at the root directory.
• Avoiding unnecessary redirects or access restrictions.
• Including only authorized, known partners.
• Validating your file after each change using trusted tools.

Staying close to industry guidance not only prevents ad fraud but also keeps your inventory attractive to top buyers.

Stay Alert and Proactive with Changes

Programmatic advertising moves fast. Suppliers merge, policies shift, and account numbers change. Immediate awareness can help you fix issues before they hit your revenue. Consider setting up:

• Email alerts from your monitoring tools when the file changes.
• Notifications from your hosting or CMS for file edits.
• Alerts from your biggest demand partners if they notice a broken or missing file.

Quick action can mean the difference between a minor inconvenience and a week of lost revenue. For more best practices and a deeper dive, check out the detailed breakdown from Databeat.

Small habits—routine checks, smart automation, and strong partner communication—are the backbone of strong ads.txt management. Treat these tasks like tending a garden: a bit of effort each week keeps your ad earnings healthy and growing.

Conclusion

A readable, error-free ads.txt file does more than check a box. It guards against fraud, opens the door to new ad buyers, and keeps your partnerships thriving. When you make readability and accuracy a habit, your site stands out as a trusted place for quality programmatic deals.

Regular checks and clear formatting are like tending a well-kept storefront: they welcome demand partners, build trust, and set you up for stronger, more reliable revenue. Every update and validation you perform today pays you back in partner confidence and smooth earnings tomorrow.

Thank you for dedicating the time to protect and grow your site’s ad value. Keep your ads.txt honest, open, and easy to find—the small details you manage will shape your results. If you have questions or want to share your experience, add your voice below. There’s always more to learn, and your story helps others stay sharp, too.