Are URL shorteners like bit.ly truly bad for email deliverability?

Yes, using public URL shorteners like Bitly in emails is generally bad for deliverability. They are often associated with spam and phishing, leading to a poor reputation with mailbox providers. This can cause your emails to be flagged as spam or blocked, even if your content is legitimate. For more details, see our article on whether it's bad to use Bitly links .

What is the main risk of using a public URL shortener?

The main risk is the shared reputation of the shortener's domain. If other users of the service engage in spamming or malicious activities, the shortener's domain acquires a bad reputation (or blocklist listing), which then negatively impacts your emails, even if you're a legitimate sender. This is a common factor in why your emails might go to spam .

Are branded or private link shorteners a better option?

Yes, branded link shorteners (e.g., links.yourdomain.com) are a much safer alternative. Because these links use your own domain, you control their reputation. This maintains transparency and trust with mailbox providers, improving your email deliverability rates . Just ensure your branded shortener isn't configured as an open redirect.

Does masking a bit.ly link help improve deliverability?

No, masking a Bitly link (e.g., by using an HTML redirect) does not help deliverability and can even make it worse. Mailbox providers can detect such attempts to obscure the true link, further raising suspicion. Focus on transparent and direct linking practices instead. You can learn more about masking Bitly links in our dedicated article.

Are URL shorteners like bit.ly bad for email deliverability? - Sender reputation - Email deliverability - Knowledge base

When managing email campaigns, especially transactional or marketing emails, the length of a URL can sometimes be a concern. Shortening services like

Bitly offer a convenient way to condense long links. While seemingly harmless and even beneficial for aesthetics or character limits, their impact on email deliverability is a critical consideration for any sender.

The unfortunate reality is that using generic URL shorteners can significantly hinder your ability to reach the inbox. Email service providers (ESPs) and mailbox providers often view these shortened links with suspicion due to their historical association with malicious activities like spam and phishing. This scrutiny can lead to your legitimate emails being flagged, delayed, or outright rejected, impacting your sender reputation.

The inherent risks of public URL shorteners

The fundamental issue with public URL shorteners stems from their shared nature. When you use a service like

TinyURL or Bitly, you are not using your own domain, but rather a subdomain or path on the shortener's domain. This means your links share the reputation of every other user on that service. If spammers or malicious actors exploit the shortener, the entire domain's reputation suffers, and your emails, by association, can be impacted.

Mailbox providers are constantly on the lookout for suspicious patterns. Public URL shorteners have long been a favored tool for those attempting to conceal the true destination of their links. This has led to a general distrust, causing filters to become more aggressive when they encounter these domains. As Word to the Wise noted, this issue with Bitly (and similar services) has been a deliverability concern for over a decade, meaning it's a deeply ingrained problem.

The convenience of these services, which often include click tracking, is not worth the risk to your email program. Even if your content is legitimate, the association with a domain frequently used by bad actors can lead to your emails being marked as spam. This can impact your overall domain reputation and could potentially land your sending IPs on an email blocklist (or blacklist).

Many email service providers (ESPs) wrap links in their own tracking domains, which often results in a double redirect if you also use a public shortener. Each additional redirect introduces another point of potential failure and can further complicate how mailbox providers assess the legitimacy of your links. This layered redirection can sometimes resemble patterns used in phishing attempts, increasing the likelihood of your email being flagged.

Domain reputation and trust

Mailbox providers rely heavily on domain reputation to determine whether an email is trustworthy. When you use a public URL shortener, the reputation of that shared shortener domain directly influences the deliverability of your emails. If that domain has a poor reputation due to widespread abuse, your emails will inherit that negative association. This is why many ESPs like

Gmail are increasingly blocking messages containing them.

A key aspect of email authentication is transparency. When a recipient sees a link in an email, they should ideally be able to identify its destination before clicking. URL shorteners, by their very nature, obscure this information, which raises a red flag for spam filters and security systems. This lack of transparency undermines trust and increases the likelihood of emails being diverted to the spam folder.

The risk is amplified if the shortener's domain itself ends up on a major email blocklist (or blacklist). When a domain is blacklisted, any email containing links from that domain, regardless of the sender's own reputation, faces a high probability of being blocked or junked. This is an immediate and severe impact on your email deliverability, leading to missed opportunities and damaged sender credibility. Understanding how your links interact with blocklists is crucial.

This challenge is directly related to your overall email deliverability issues. If your emails are consistently landing in spam folders or being rejected, link shorteners could be a contributing factor. It's often one of the first things I check when diagnosing such problems. For more insights on this, you can read about how URL shorteners and domain reputation impact deliverability.

Branded links and avoiding misconfigurations

While public URL shorteners pose significant deliverability risks, branded or private link shorteners offer a viable alternative. These allow you to use your own domain, or a subdomain of it, for shortened links, such as links.yourdomain.com/shortlink. This approach means you maintain full control over the link's reputation, as it's tied directly to your own sending domain. This is generally acceptable to mailbox providers because it offers transparency and aligns with your brand's established identity.

However, it's crucial that even private link shorteners are properly configured and secured to prevent abuse. A misconfigured private shortener, particularly one with a publicly accessible API or web page that allows anyone to shorten any link (not just those on your domain), can quickly become a target for spammers. If this happens, your custom shortener domain could end up on blocklists, causing the same deliverability problems as public services. It’s important to understand how public URL shorteners affect email deliverability.

Beyond explicit shorteners, be wary of stealth redirection. This occurs when a redirect domain is kept, but the payload is loaded in an i-frame or through other methods that obscure the final destination. Whether intentional or accidental, such practices can trigger spam filters due to their deceptive nature. It's always best to ensure your redirects are transparent and directly lead to the expected content.

Some organizations use internal redirection URLs that allow for editable destinations via a query string. While this can be functional, it's crucial to ensure these systems are robust and cannot be tricked into redirecting to external or malicious domains. A well-secured internal redirect should always keep traffic on your own site, even if the specific page is invalid, redirecting to your homepage instead. This helps maintain trust and prevents unintended abuses that could lead to deliverability problems.

Public URL shorteners

Reputation risk: Shares reputation with all users, making you vulnerable to others' spamming activities.
Lack of control: You have no say in the shortener's policies or how its domain is used by others.
Deliverability impact: High likelihood of emails being flagged as spam by Outlook or Yahoo.
Transparency: Hides the final destination, which can erode recipient trust.

Final thoughts on URL shorteners and deliverability

I generally advise against using public URL shorteners like Bitly in your email campaigns. The potential for deliverability issues, including landing on a blacklist or blocklist, far outweighs the aesthetic or tracking benefits they might offer. It’s always safer to use full, transparent URLs, or at minimum, a branded link shortener that you control fully and securely. This strategy helps maintain a strong sender reputation and ensures your messages reliably reach the inbox.

Prioritizing transparency and building trust with mailbox providers and recipients is key to successful email deliverability. While character limits might seem like a good reason to shorten links, particularly in contexts like social media, email deliverability has different, more stringent requirements. Always choose practices that enhance your sender reputation and ensure clear, direct communication.

Views from the trenches

Best practices

Always use full, original URLs in your email content whenever possible to ensure transparency and avoid reputation issues associated with third-party shorteners.

If link shortening is necessary (e.g., for analytics or aesthetic reasons), use a branded shortener domain that you own and control.

Ensure any custom link shortener you set up is secured against open abuse to prevent spammers from leveraging your domain.

Regularly monitor your domain's reputation with tools like Google Postmaster Tools to catch any issues early.

Keep redirects simple and direct, avoiding complex or stealthy redirection methods that can trigger spam filters.

Common pitfalls

Using generic, public URL shorteners like Bitly, TinyURL, or Rebrandly, which are often associated with spam and malicious activity.

Not securing custom link shorteners, allowing them to be exploited by spammers and damaging your own domain's reputation.

Employing multiple layers of redirection (e.g., ESP click tracking + URL shortener) which can increase the likelihood of deliverability issues.

Assuming that a short link is inherently better for email marketing without considering the reputation impact.

Ignoring warnings from mailbox providers or blocklists about domains used for shortened links.

Expert tips

Even if your emails have low click-through rates, using shortened links isn't the solution. Focus on improving content and targeting.

Consider that many ESPs already wrap your links for tracking, adding another shortener creates unnecessary redirects.

A branded link shortener (e.g., links.yourdomain.com) is generally safe, as long as it's not configured to be an open redirect.

Regularly check if your domain (or any domains you link to) is on any major blocklists using a blocklist checker.

For cold emails, avoid links entirely or use very few, as links can often negatively impact deliverability.

Expert view

Expert from Email Geeks says that Bitly is often abused and has a bad reputation attached to it, which is generally the case for many third-party domains you do not control.

2021-11-19 - Email Geeks

Expert view

Expert from Email Geeks says that any public link shortener should be avoided, but private ones can be acceptable.

2021-11-19 - Email Geeks