Finding comprehensive lists of disposable email domains is a common challenge for those looking to maintain clean email lists and prevent abuse. While many public and private sources exist, the dynamic nature of these domains means that a truly comprehensive list requires continuous updating and careful vetting. Many marketers create and maintain their own lists, often starting from publicly available resources and refining them based on their specific needs and observed activity.
Key findings
Public repositories: GitHub hosts several community-maintained lists of disposable email domains, such as the disposable-email-domains repository. These are often updated by community contributions.
Dynamic nature: Disposable email domains (also known as temporary email accounts) frequently appear and disappear, making static lists quickly outdated. This necessitates a proactive approach to list maintenance.
Purpose-driven blocking: The effectiveness of blocking disposable email domains depends heavily on what you're trying to achieve. Some major email providers (e.g., Gmail, Yahoo) can also function as disposable email accounts if users frequently mark emails as spam, highlighting that a domain's status can be subjective.
Verification services: While some email validation services detect disposable domains, their databases also require constant updates to remain effective. It is always a good idea to perform accurate email list verification.
Key considerations
Manual review: Any third-party blocklist or blacklist of disposable domains should be reviewed before being fully implemented, as some lists may incorrectly include legitimate catch-all domains or non-disposable services.
Updating frequency: When choosing a list, consider how frequently it is updated. Given the rapid emergence of new disposable email services, a list that is not regularly maintained can quickly become ineffective.
Balancing strictness: Implementing overly strict blocking can inadvertently prevent legitimate users from signing up. It's crucial to balance the need to prevent abuse with the desire to maximize user acquisition.
Beyond domain lists: Consider broader strategies to prevent disposable email signups, such as CAPTCHAs, email verification steps, or behavioral analytics, which can be more effective than a static list alone.
What email marketers say
Email marketers frequently discuss the challenges of managing disposable email addresses, often seeking shared resources to block them effectively. They emphasize the importance of having up-to-date lists to maintain email list hygiene and prevent issues like spam complaints or fraudulent sign-ups. Many have experimented with creating their own internal blocklists, recognizing that publicly available resources, while helpful, may not always be exhaustive or current enough for their specific needs.
Key opinions
DIY lists: Many marketers prefer to build and maintain their own lists of disposable domains, often starting with public data and adding domains based on their own observations and experiences.
Collaboration interest: There's a strong interest within the community for a collaborative and frequently updated list of disposable email domains to share best practices and resources.
Limitations of validation software: While email validation services are useful, marketers note that they often struggle to keep up with the constant emergence of new disposable domains.
Variety of sources: Marketers source their initial lists from various places, including GitHub, Reddit, and specific vendor-provided lists (e.g., from HubSpot).
Key considerations
Maintenance burden: Maintaining an extensive and current blocklist of disposable domains is a significant, ongoing task.
Granularity: Marketers should consider how granular they want their blocking to be. For example, blocking only known disposable domains versus also identifying and filtering bot email addresses.
Impact on deliverability: Using static or outdated disposable domain lists can lead to inadvertently blocking legitimate subscribers, which can hurt list growth and overall deliverability. This also includes understanding which email domains and addresses marketers should avoid.
Alternative approaches: Besides lists, consider implementing other measures to prevent abuse, such as stronger signup verification or analyzing user behavior beyond just the email domain.
Marketer view
Marketer from Email Geeks explains they previously compiled a list of over 700 disposable email domains, which they blocked from being accepted for sign-ups, highlighting the ongoing effort required to maintain such a list.
10 Aug 2021 - Email Geeks
Marketer view
Marketer from Reddit shares that they found a list of approximately 1,000 disposable domains on Reddit itself, indicating that community forums can be valuable sources for initial data.
10 Aug 2021 - Reddit
What the experts say
Experts in email deliverability and anti-abuse emphasize that a nuanced understanding is required when dealing with disposable email domains. They caution against blindly trusting third-party lists, as these can sometimes contain legitimate catch-all domains or general email providers. The core objective behind blocking these domains should drive the strategy, focusing on preventing specific types of abuse rather than simply rejecting all temporary addresses.
Key opinions
List vetting: Experts advise reviewing any third-party lists of disposable domains before implementation, as they might inadvertently include legitimate catch-all domains.
Redefining 'disposable': Some experts argue that even major providers like Yahoo or Gmail can be considered 'disposable' if users frequently mark emails as spam, highlighting that the concept depends on a sender's goals.
Focus on credentials: A key concern for experts is identifying domains that do not require a password or other credentials to access the mail store, as these are more prone to abuse.
Beyond the domain: The focus should shift from merely the domain itself to the underlying behavior or characteristics that define a truly disposable or problematic email address.
Key considerations
Goal alignment: Before implementing any blocking strategy, clarify what you're trying to accomplish. Is it to reduce spam complaints, prevent fraudulent sign-ups, or improve data quality?
Dynamic assessment: Rather than relying solely on static blacklists (or blocklists), consider implementing dynamic checks that assess an email address's characteristics in real-time.
Understanding abuse: Focus on the behaviors associated with disposable email use (e.g., high bounce rates, spam trap hits) rather than just the domains. Understanding how spam traps work is critical.
Reputation implications: Be mindful that overly aggressive blocking can impact your sender reputation or lead to false positives. It's often better to monitor and react to problematic engagement than to preemptively block a wide range of domains without sufficient data.
Expert view
Deliverability Expert from Email Geeks warns against taking third-party lists of disposable email domains at face value, as some may include catch-all domains that are not truly disposable.
10 Aug 2021 - Email Geeks
Expert view
Deliverability Expert from Spam Resource notes that the term 'disposable' can apply to any email address, even from major providers like Gmail, if a user decides to treat it as such by marking emails as spam, challenging traditional definitions.
15 Jan 2024 - Spam Resource
What the documentation says
Technical documentation and research often delve into the mechanics of disposable email domains, explaining how they operate and why they pose a challenge for email senders. These sources highlight that a comprehensive understanding involves not just identifying domains, but also comprehending the underlying services that facilitate temporary email creation, the reasons for their use, and the technical indicators that can help distinguish them from legitimate email services.
Key findings
Service monitoring: Providers of comprehensive lists actively monitor numerous throwaway email service providers to capture newly rotated domains.
WHOIS lookup: WHOIS lookup services can be used to search for an email address and determine which domain names are associated with it, aiding in the identification of temporary services.
Automated detection: Technical solutions often involve pre-integrated lists of domains known to offer temporary email services, streamlining the detection process for platforms like WordPress.
Database access: Some large lists of disposable email domains are maintained as databases that can be requested for integration into internal systems.
Key considerations
Scalability: Consider the scalability of your blocking solution. Manual list maintenance becomes unsustainable as the number of disposable domains grows.
Integration: Evaluate how easily a disposable domain list can be integrated into your existing systems (e.g., signup forms, email validation processes). Consider if you should block disposable email addresses from your email list.
API vs. Static list: Decide whether a regularly updated API service for disposable domains is more suitable than a static, downloadable list, given the dynamic nature of these services. This ties into considering the most current lists for email suppression.
Maintaining relevance: A list's value diminishes if it's not frequently refreshed. Look for sources with clear update cycles or community involvement.
Technical article
GitHub documentation for disposable-email-domains states that the repository offers a list of domains frequently used for creating dummy user accounts to spam or abuse services, providing a public, community-maintained resource.
01 Jan 2024 - GitHub
Technical article
WhoisXML API documentation mentions that their disposable email domains list contains over 125,000 temporary and fake domains, actively monitoring more than 2,000 throwaway email service providers to ensure comprehensiveness.