We have implemented a validation check that ensures the correct format and performs SMTP validation on the recipient's MX. This works well, but since this is a hackathon, we want to push the envelope and innovate further.
B2B sales, especially in the tech industry, often deal with customers who have a web presence. However, these contact lists can become outdated over time due to employee turnover and company changes. In addition to validating the email address using SMTP, let's also confirm that the website is still active and being invested in. This further reduces the risk of sending emails to expired domains when re-verifying dated contact lists or performing a sanity check on an existing one.
What it does
The team recognizes that the methodologies listed below are not new to the email industry. However, we have decided to go beyond simply building a tool that validates emails. Our tool also provides additional information for email lookups, such as checking for an active website and logo.
How we built it
The project uses internally built APIs and tools, including a validation API endpoint, a PHP script for SMTP validation, and a business scraping tool.
Challenges we ran into
- Some receiving MXs had significant cooldown times between sends, particularly with Cox.net emails. The validated list provided frequently worked once, then would not work and return:
452 4.1.0 <sender> server temporarily unavailable. Refer to Error Codes section at [https://www.cox.com/residential/support/email-error-codes.html](https://www.cox.com/residential/support/email-error-codes.html) for more information. AUP#CXMXRT
- Intelligent management of proxy IPs rotating around this cooldown for a scalable long-term fix. Long shot, but it may be worth a conversation with the Cox business team for partnership.
- Cloudflare-hosted MX rejected requests that do not have a reverse IP lookup.
Accomplishments that we're proud of
By merging multiple sources, we are able to build a better picture of what deliverability means in the email industry. This was a wonderful exercise in the space.
What's next for B2B Email + Business Web Validation
Future work includes adding multiple line input, CSV import/export, intelligent management of caching and validating against the same MX for a domain, scaling to more requests, and IP proxy rotation. Recent developments in AI such as LLMs may add significant value to identifying top priority leads and contacts based on user goals and is worth exploration.