u/TeamPuzzleInbox

Hi everyone,

Its Jame from the PuzzleInbox analytics team. I want to do a short post on how you can send your first 100,000 cold emails.

Cold Email is not easy. It takes time to build you infra and even takes more time and learning to manage it properly. Sending 100,000 cold emails makes sense if you are actually delivering to the inbox. For that:

As of 3rd of July, Google Workspace has the best deliverability for cold emails in the market. Each Inbox would cost you somewhere like $2.5-$3 depending on the volume you buy them.

We recommend sending 12 cold 12 warm emails per inbox, if you want to keep your inboxes safe and delivering, so that is 360 cold emails if you calculate the month as 30 days.

You would need around 270 inboxes that would cost anywhere from 650-800 dollars. You would need a sending tool to send and manage campaigns. Those tools would cost $50-$100. Also you would need a lead finder that can provide you verified contacts. Price really depends here on where you use as a provider.

In terms of what you can expect to get out of 100,000 cold emails:

Heavily dependent on your offer. We see 100-900 leads generated from our clients and through our research. That would give you a cost per lead of $2 on average. Disclaimer, this really depends on your offer. It could be $0.5 and it could be $15 too.

Looking forward to questions and connecting with cold emailers.

Hey everyone,

Hope everyone is doing well. I want to do a post on our experience managing 115,000 inboxes and sending 10 million plus emails a month.

We have been doing a lot of testing when it comes to deliverability. Offer and infra is currently what matters. When you have a good offer with a strong infra you start booking a lot of meetings and generating a interested leads.

We use claude to generate cold email copies and offers. What we've learned after burning through a lot of variations:

• Offer first, copy second. No amount of clever writing saves a weak offer. We now spend 80% of the time on the offer itself the promise, the specificity, the risk reversal and let Claude iterate on the wording once the offer is locked in.
• One variable at a time. We A-B one thing per test subject line, opener CTA offer angle. Testing five things at once teaches you nothing.
• Reply rate is the only metric we trust. Everything upstream of a reply is useless now. If replies are flat it's the offer or the targeting almost never the copy.

Happy to answer questions on any of this.

Hi everyone,

I am from the Puzzle Inbox Analytics team. I wanted to do a post explaining the different ESP's for cold email like Google Workspace vs Office 365 and SMTP as a mailbox company that has over 115,000 cold email inboxes deployed.

As of 1st of July the best performing ESP is undoubtably GWS. It performs 3-4x better than Office 365 and maybe 10x better than SMTP. As a provider that tried it all we currently offer only Office 365 and GWS. SMTP is really fragile and is not meant for cold emailing. SMTP inboxes could do well for a few weeks but after getting spam reports, they will start landing to SPAM. Office 365 was doing good between November 2025 to March 2026 but now we are also seeing a decline in deliverability on that side.

Google Workspace we recommend 12 cold 12 warm emails. This is not a limit we put, this is standard cold email practices we recommend to mitigate spam etc.

We also believe it makes sense to do 2 inboxes per domain and 3 inboxes per domain. If you. follow these, your inboxes will be safe and delivering.

Looking to explore different opinions and connecting with every single cold emailer. Thank you!

Hey everyone,

I am from the PuzzleInbox team. I wanted to do a post more for engaging with other cold emailers. Our team has been doing cold email for over 8 years now and officially we have been provisioning mailboxes for the last 3-4 years. We track and use over 100-150 thousand Google and Office 365 Inboxes.

Feel free to ask questions on deliverability, scripts, inboxes, warm-up, infra. Looking forward to engaging with you all!

Hi everyone,

I am from the PuzzleInbox team. I wanted to do a short post on how to increase your cold email reply rates.

We track over 100,000 mailboxes and therefore we are able to investigate the factors that cause deliverability issues.

1. Never send HTML or links in the first cold email. This is a easy fix but some people keep doing it. Your domains will be blacklisted pretty quick and you will start landing to spam or even getting direct bounces to your cold emails.

2. Never send more than 12 cold emails from Google and Office 365 mailboxes and 3 from the 100 inboxes per domain Office 365 setup. Here is why. Its not 2020 anymore, Google and Outlook have stricter limits when it comes to cold email. If you want to make sure you deliver to the inbox. I would heavily recommend to stay below this limit.

3. Your cold email copy and offer is key. Whatever industry you are in or whatever you are trying to accomplish with cold email. Make sure you have a attractive offer. You can A/B test different offers to investigate the outcomes of different offers. On the copy side never have your copy longer than 100 words and make sure to remove spam words. P.S there is free spam checkers when you google it.

4. Leads you are targeting. Stay away from saturated b2b leads. Try to focus on acquiring leads that are local. Another option would be to look out for providers that provide up to date b2b leads and not popular amongst other users. The more popular the provider is the more likely the leads are targeted by thousands of users in a day to day basis.

I can drop down more info here but I feel like this is a good starting point. Big thanks to everyone. Happy to answer questions. Thank You!!