An In-Depth Cold Email Platform Review

In this paper, I dive into the what and how of cold emailing – what to know, and how to determine the best platform to execute. After reviewing 32 platforms built to perform bulk cold emails, my team and I came up with a shortlist of 5 we know provide a data + outreach solution for executing cold email campaigns (as opposed to only providing the ability to email). Towards the middle, you will find a detailed chart showing how all 5 cold emailing platforms compare based on specifics like data quality, copy customizability and GDPR compliance.

For whom is this analysis the most beneficial?

I would recommend this paper to anyone sending cold emails first and foremost. Regardless of how much they are doing or how long they have been doing it. Some of the points we reviewed during the analysis of each platform apply to all use cases of cold emailing (e.g. ways in which data is gathered and verified, and how to ensure your process is data is high-quality).  

Why did I spend my time creating this cold email platform comparison?

In the last few years, more and more platforms have emerged offering similar value propositions so the market has become clouded and it has become very difficult to discover which platform provides the most intuitive sequence-building UI, the best algorithms for determining positive replies, the integrations with the CRM you use… and most importantly… which has the most accurate and rigorous data scraping/verifying process?

The reasons I chose these 5 platforms for analysis is based on a survey I sent out to my colleagues and connections asking them what platform they use for cold emailing.

Then, I eliminated any that do not (a) include the ability to source leads from within the dashboard (either from a database or on demand), and (b) include functionality necessary to send rule-based email sequences. From there, I eliminated the strictly managed services platforms like LeadGenius, OutboundWorks or RevBoss. If there are other platforms you would like me to take a look at let me know and I’ll add them to this analysis or do a part 2 of this blog post.

The thought process…

Wow. This was an undertaking… I started this process by compiling a list of platforms I’ve used, added those I’ve heard of, and finally asked my colleagues and founders I’m connected with which they prefer for sending cold emails. I had a huge list at this point: Woodpecker Growbots QuickMail
Hubsell OutboundWorks Prospect BANT
RevBoss SalesHandy SwipeMail SmartReach
SalesSeek TruCadence Yesware Sellulose
FreshSales Growlabs AnyLeads Klenty
ReplyUp Sendbloom ToutApp
PersistIQ Aweber Snapmail FullContact
Reply Datananas SalesHandy GmailMeter

This is clearly too large of a list and too disparate to do a valuable side-by-side for you (the good news is, I’ll be doing more of these reviews focusing on products that are comparable to one another).

So, I decided to make this first comparison of a particular type of platform and use-case;

Here are the requirements that I am focusing on, for this first review:

  • Must include a database of leads to draw from or an in-house team to gather and verify data ad hoc.
  • Email sequence setup and management.
  • Dynamic text and follow-up rules.
  • Integrations with top CRMs.
  • Not be a ‘managed’-only platform (meaning, they setup and run campaigns for you).

My research process

To find out, I tested out and spent time with reps from each of these cold-email-focused platforms to discover which is truly the best platform to do (1) database-building and (2) sending of cold emails all from one dashboard:

  • Autoklose
  • Foundly
  • Growbots
  • Growlabs
  • Hubsell

Although I have used three of platforms extensively (Growbots, and Growlabs), I have not had much experience with the other two. So, I first reviewed their websites and product pages. Then, I scheduled demo’s under’s use case (multiple B2B clients in different sectors). On these demo’s I focused on getting the 36 answers you see in the chart below. Some required more than one phone call and all required multiple emails to really dig out the accurate answers to these tough questions.

These 5 email platforms cannot continue onboarding clients without:

  • Strong user-wide metrics like average inboxing percentages, open rates and positive reply rates and more.
  • Customer satisfaction in both the features and the data.
  • Strategic support to ensure your team is not doing anything too risky (hint: EU-GPDR and the ePrivacy regulation).

Using an email platform which provides the data can benefit you in two ways;

  1. It’s incredibly fast and convenient.
  2. And, because they have more control over the data quality as well as email customization based on that data, their customers tend to have higher average open and lower bounce rates than those who separate their data and email service providers.

Average bounce rate is the key figure to look at here because it shows how good the data truly is. You may know of a few tools or services meant to help you gather your own data. Some larger ones are AnyLeads and Snovio.

But, how are those tools finding that data?

And when they find an email, how do they verify it’s real and being used?

Most rely heavily on LinkedIn’s code to grab name and company email domain and then use soft-pings to ‘verify’ the email authenticity for you, but none of these tools will continually monitor the *bounce rate of emails sent to that inbox and stop providing those bad emails. My point is, if you are planning to scrape for mass-cold-emailing operations, use a platform with the verified data as well as the sequence sending capabilities.

**Inboxing is determined by: quality of the prospect data, open/click rates of emails sent by your domain, send volume, consistency.

A quick intro to myself

I’m a Growth Marketing Executive in Chicago focused on helping companies create growth-minded cultures and processes. Over the last 10 years, I’ve built and tested cold emailing campaigns on hundreds of audiences using over a dozen email platforms sending through alternating ESPs and through Gmail/Outlook. I used data I bought from providers like Clearbit, ZoomInfo and Bookyourdata. I’ve also created scrapers, installed Chrome extensions and hired teams to enrich sheets upon sheets of data manually.

But those days are over.

State of the union – cold emailing

Canada has the an anti-spam regulations CASL, the U.S. has the CAN-SPAM Act and there is a new reform to regulations in the EU, the General Data Protection Regulation (GDPR) which is causing a lot of discussion in the B2B sales/marketing communities. Download the entire legislation here. (Also find an easier-to-understand report from fieldfisher here explaining the e-marketing requirements of the EU states).

What is GDPR?

“GDPR is a regulation that requires businesses to protect the personal data and privacy of EU citizens for transactions that occur with(in) EU member states. And non-compliance could cost companies dearly. Here’s what every company that does business in Europe needs to know about GDPR.” – Michael Nadeau, Senior Editor, CSO

3 most important things to know about GDPR in the context of e-marketing

  1. Contact and other personal data used in an e-marketing campaigns needs to have been collected for that purpose specifically.
  2. Contact (data subject) needs to be able to exercise their right of access, right of erasure, right of rectification and right of opt-out without any barriers.
  3. Data processors (data providers) need to provide a data processing agreement to their customers defining the scope and purpose of the data processing.

The use case we’ll be discussing

Now that we have our list and an understanding of the current emailing climate, let me remind you what we are basing our final selection on:

  • Must include a database of leads to draw from or an in-house team to gather and verify data ad hoc.
  • Email sequence setup and management.
  • Dynamic text and follow-up rules.
  • Integrations with top CRMs.
  • Not be a ‘managed’ campaign platform.

The contenders

Autoklose – This is a lightweight platform built for cold email automation with the database of verified leads to support your team’s needs. Autoklose has a great Salesforce integration allowing you to do add custom text in your emails based on fields in SF fields. – Based off of an email scraping tool, now offers email sequence-building/sending and ad hoc email lists. They are the cheap option in terms of data and usage.

Growbots – One of the first to provide an easy-to-use UI with both grabbing and sending capabilities. They captured huge market share with their offering early on. The UI/UX in Growbots is great, and they provide data for you.

Growlabs – Very similar to Growbots – with some differentiators. They UI is good, and the Salesforce Integration is excellent.

Hubsell – This platform, was built under the strict email regulations of EU so it has everything you need to avoid spam filters. It also differentiates itself from these others by doing their data research for you ad hoc (gathering fresh verified leads for you as you request them, instead of having you pull them down from a pre-filled database).

The stats

Here is a link to my Google sheet where I will be adding more reviews of managed platforms and CRMs in the future:



(I know there’s a lot here, but I did what I could to fit it all into an image. Please zoom in to get a clear view of the cells)



Beyond the key points charted above, there are a few key differentiators among each, as well as downsides to consider:


What’s good about Autoklose?

  • Company industry criteria can be quite in-depth with SIC code filters to use on certain industries/verticals.
  • Creation of custom fields specific to your business (e.g. how many times a user did this in your app or on your site) which can be pulled from your CRM

But… there are downsides:

  • Data coverage is only in the US
  • Bounce rate is in the double digits
  • Very little customization options for email copy


What’s good about Foundly?

  • Pricing is their key competitive advantage.
  • Data is researched ad hoc

But… there are downsides:

  • They will add emails which are only determined through pattern-recognition (
  • They did not disclose their bounce rate.


What’s good about Growbots?

  • Pre-loaded sequence templates for you to use and customize.
  • Great UI/UX makes the on-boarding easy.
  • Pre-loaded email templates you can customize for your use case.

But… there are downsides:

  • Bounce rate can reach double digits.
  • Content customization is limited to mainly static placeholders.


What’s good about Growlabs?

  • Bilateral Salesforce integration allowing very easy syncing of data.
  • The dashboard has a great UI/UX.
  • Only on the list to have a zapier integration.

But… there are downsides:

  • They are strict about emailing B2C and will not allow uploads of or sends to any personal emails.
  • No reimbursement for bounces.


What’s good about Hubsell?

  • On-demand researched data which you can cherry pick in the approval stage delivered with 20+ variables containing categorical data per row.
  • Copy can be customized based on categorical data such as gender, seniority, industry, department and more using an if this then that logic.
  • Among the lowest bounce rate with auto data credit reimbursement.

But… there are downsides:

  • Steep learning curve makes adoption rate slow.
  • On higher end of cost per prospect.

The conclusion

Thank you for taking the time to review this research. My team and I spent hours gathering it. And, you are still owed a recommendation…

My current recommendation for [almost every] cold-messaging use cases is going to be Hubsell out of New York and Berlin. Though one of the newest and less built-out of the group, they blew me away with their data quality, customization features and knowledge of spam filters.

To add context my conclusion here is why Hubsell has been the best for the most recent projects I’ve been involved in:

  1. Data Quality – Hubsell’s ad hoc data gathering has increased the quality of data a ton. An anecdote to put into perspective how important the data is; when I used Growlabs, their data filter provided me with tons of mismatches which translated into more of my time excluding contacts from filters sometimes over 5000 in total. Further, when I would upload my own data, which I gathered from a very good source, they would scrub out over 70% of the contacts for their own reasons (my sense is they hoped to force me to buy more from their DB). Using Hubsell, I spend very little time approving contacts and am able to load my own verified data.
  2. Copy Customization – Using Hubsell’s dynamic text, I am able to create one sequence for multiple personas in a company/vertical (using if-this-then-that statements). I can even go as far as to send one version of the copy to women and an entirely different version to men. This practice is necessary when sending in languages where verbs are conjugated differently based on gender, but can also be useful for other language/tone customizations.
  3. Customer success – Hubsell’s team has been the most help with onboarding needs as well as best practices. They have gone above/beyond – being both supportive and helping with strategy.  
  4. GDPR Compliance – Lately this has caused all other platforms to remove their EU contacts from their databases entirely. Hubsell built their platform under EU’s strict emailing guidelines and had planned ahead for GDPR so their system is much more valuable under these new regs.

And… as of today this was published, they have added LinkedIn as a channel through which the user can conduct automated outreach.
Listen to the recording of Hubsell’s founder and I discussing their platform and this report:

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