Garry Tan

mailX by mailwarm - Email deliverability toolkit for humans and AI agents

Your emails go to spam. mailX shows you why, and how to fix it in seconds with clear answers and exact steps. Built for humans and AI agents. API and MCP ready.

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Thami Benjelloun

Like most founders, email has been our #1 sales channel since our first startup in Paris. That’s what led us to build @Mailwarm and work on email deliverability since 2020.
And one thing became clear: your emails don’t land in the inbox by magic.

Over the years with mailwarm (YC S20, #1 Product of the Day for March 4th, 2020 🏆), we’ve helped thousands of teams improve deliverability. And we kept seeing the same thing:

  • People either don’t know what’s wrong…

  • Or they see the data, but don’t know how to fix it.

So they guess.

That’s why we built mailX.

Run a check -> understand what’s broken -> fix it with clear steps.
No signup. No guesswork.

We also made it usable by AI agents, not just humans.

If email is part of your growth, tell me in comment how you’re using it. We’ll take a look and help you improve it.

Manal Essalek
Othman Katim

@thamibenjelloun Emailing made me meet great people and build an amazing team!

Ronak Agarwal

@thamibenjelloun Congratulations! 🏆

Ruben Lozano

@thamibenjelloun congratulations team!! This is definitely a solution that many of us need!

Maria Anosova 🔥

@thamibenjelloun Email deliverability is painful because it’s not obvious. You send emails, replies go down, and suddenly everyone starts guessing. Does mailX remove that guesswork?

Bengeekly

@thamibenjelloun  @maria_anosova It does in the majority of the cases, we are building a set of tools to manage the rest. Mailwarm for deliverability, and Mailadept if you need to go deeper and have a human to help you.

Thami Benjelloun

@maria_anosova Yes, exactly. mailX removes the first layer of guesswork: it tells you what’s broken, why it matters, and what to fix first. Most teams don’t need more raw data. They need a clear diagnosis before they start changing random things.

Nika

In the future, will the tool be able to create such an email and settings on its own so it will not end up in the spam? Like the whole automation of the process instead of suggestions.

Manal Essalek

@busmark_w_nika Definitely something to keep in mind for our Roadmap 😉

Othman Katim

Hi @busmark_w_nika, thank you for raising this!

That's the question we keep asking ourselves. Today, we surface what's broken and guide the fix, full automation is the logical next step. Which part of the setup would you most want automated first?

Thami Benjelloun

@busmark_w_nika No. Our focus is not to create the email itself and send it.

Many tools already help with copy, personalization, and sequences.

Our focus is the part after that: making sure the email has the best chance to land in the inbox.

So mailX diagnoses what is wrong, through the web app or through AI agents via API & MCP.

The future for us is more about helping agents check, fix, and monitor deliverability safely, not replacing the creative part.

Srinivas Narra

@busmark_w_nika  @thamibenjelloun That would be a huge relief. Right now, when my company email doesnt show up, i have to check 3 places, thunderbolt imap settings. spam/junk folders, google workspace settings.

Naim Azoutar

  @srinivas_narra Exactly 😅 And half the frustration is not even knowing where the problem actually is.

Sometimes it’s an IMAP/client issue, sometimes Google Workspace, sometimes authentication, sometimes spam filtering… and you end up debugging across 4 different dashboards just to understand why an email disappeared.

Nika

@thamibenjelloun aaa, okay, I thought that in most cases the cause of landing in the spam is the fact that the email contained some spam-triggering words. But there are more reasons for that.

Bengeekly

@thamibenjelloun  @busmark_w_nika Learning of the day: Email is an old technology built with 0 safety! When you tell a server to send an email, you literally give him the From and To.
So you can send an email from any domain even if I don't own it!!!
This ugly protocols: SPF, DMARC, DKIM have been created after to solve this, it's like an ID that allow to say I own the domain. If you don't have it, you are trying to enter to a party without having your ID.
In this case the recipient provider decide if he reject, accept or put in spam.

Then there is your Domain reputation + Content analysis :)

Bengeekly

@busmark_w_nika MailX itself no, but that's the magic of MCP and AI agent. You can Ask Claude to use MailX for the recommendations and set your actuals tools

Bengeekly

Hey Product Hunt 👋

I'm Amine, co-founder of mailX. Huge thanks to @garrytan for hunting us today 🙏

After 6 years in email deliverability and building Mailwarm (YC S20), I keep seeing teams spend weeks rewriting subject lines, A/B testing send times, and buying warmup tools while they have a 5-minute problem they don't know is a problem. Missing DMARC. Broken SPF. A DKIM key that was never rotated. Boring stuff with scary names, ignored while everyone optimizes copy.

These protocols exist for a reason: they're your domain's ID card. They're how Gmail and Microsoft decide whether to trust you.

We built mailX to fix that. Ask the AI agent and it'll diagnose your setup and walk you through every step. Prefer to do it yourself? There's a human interface for that too. And every report is shareable, so you can hand it straight to an expert if you want a second pair of eyes.

The whole team is here today to answer your hardest deliverability questions 👇
Proud to work with all of you @thamibenjelloun @othman_katim @karimbenkeroum @manal_essalek1 @naimz @daniel_nwankwo

Daniel Nwankwo
@bengeekly Thank you. It’s been so fun working with you and the team🎉🎉
Thami Benjelloun

@garrytan  @othman_katim  @karimbenkeroum  @manal_essalek1  @naimz  @daniel_nwankwo  @bengeekly and all the others. Proud of this team.

mailX is really the result of different strengths coming together: deep deliverability experience, product thinking, engineering, AI workflows, customer support, and a lot of real problems we saw through Mailwarm over the years.

That’s what makes this launch special for me.

Not just a tool, but years of learning turned into something simple for humans and AI agents.

Let’s go team 🚀

Naim Azoutar

@garrytan  @othman_katim  @karimbenkeroum  @manal_essalek1  @daniel_nwankwo  @bengeekly  @thamibenjelloun Amen to that. You can feel the years of operational knowledge and customer pain points turned into something much more accessible, It’s not “AI for the sake of AI”

Big congrats to the team 👏 🤘🏻

Naim Azoutar

@bengeekly  heavy on the "boring stuff with scary names" lol. It's been lovely working with you and everyone too. To the launch and beyond 🚀

Othman Katim

The CTO vision was key here to ship it, Proud of you @bengeekly !

Bengeekly

@othman_katim Thanks

Aleksandar Blazhev

Congrats on the launch @manal_essalek1 !

Email deliverability is definitely a huge problem. Does MailX also give simple recommendations when something is wrong?

Daniel Nwankwo

@manal_essalek1  @byalexai Yes at mailX, we are focused on turning issues into actionable fixes rather than just showing raw data. So yes, the idea is to guide you with clear next steps when something is wrong, and give you the right tools to solve deliverability problems. :)

Manal Essalek

@byalexai thank you!

Yes, and that’s actually one of the most valuable parts of it. It doesn’t just flag issues, it also gives simple, actionable recommendations so you know what to fix without digging too deep.

Othman Katim

@byalexai  Would love to see ZeroHuman and MailX interacting !

Naim Azoutar

@byalexai Exactly, like my colleagues said, we want to make deliverability more actionable, not just measurable

The goal is to surface simple recommendations when something looks off, instead of expecting users to decode raw technical signals themselves.

What’s been your deliverability headache recently?

Bengeekly

@manal_essalek1  @byalexai  MailX website is built for humans to check by themselves and verify all protocols, for example here is the report for Zerohuman: https://themailx.com/report/a1d2d660-f0f8-46b9-b306-7443ba5223e4
You can check for free and we don't have any sign up wall.
Your website results is quite good, but you can make it even better.

The MCP is also open and Free, That's the step that gives you more recommendations and you can include it in any workflow you want.

Surabhi Minocha

Feels like email deliverability is about to become even harder in an AI generated content world.

Do you think inbox providers will eventually start scoring 'AI-patterned behaviour' itself, beyond just SPF/DKIM/domain reputation?

Naim Azoutar

@surabhi_minocha We’re already moving in that direction in all transparency. I think inbox providers will increasingly score behavioural patterns, not just technical authentication.

As AI-generated outreach scales, signals like engagement quality, sending behaviour, personalization depth, and human-like interactions will probably matter even more than they do today.

Daniel Nwankwo

@surabhi_minocha I think they already look at behaviour patterns like engagement, complaint signals, and sending consistency, even if they don’t call it “AI patterns” yet. If AI content makes inboxes noisier, they’ll likely just tighten how they score engagement quality, not the content type itself.

Thami Benjelloun

@surabhi_minocha Yes, and I think the issue won’t be “AI content” itself. It will be AI-scaled bad behavior: same patterns, same timing, same low relevance, too much volume. Inbox providers will punish that fast.

Are you already seeing this with AI-generated outbound?

Karim Ben

@surabhi_minocha Absolutely. I think the next layer will be behavioral reputation, not just technical reputation.

Inbox providers already analyze engagement and sending patterns, AI-generated content at scale will probably push them to detect “synthetic sender behavior” too: timing, personalization depth, reply patterns, campaign similarity, even how humans interact with the emails.

Manal Essalek

@surabhi_minocha Right now filtering is still mostly “who you are” (domain/IP/authentication) and “how people react.” But as AI-generated email scales, inbox providers will probably start looking more at behavioral and content patterns, things like repetition structures, predictability, engagement decay, sending cadence anomalies, and template fingerprints at scale.

Yuri Mihaileanu

Nice. Do you do it per email client ? I noticed that Gmail had become very annoying lately

Naim Azoutar

@yurimhln That's correct! we pay close attention to differences between email clients, especially Gmail since they’ve become much stricter lately. We optimize for rendering and deliverability across major clients (Gmail, Outlook, Apple Mail, etc.) because each behaves differently :)

Othman Katim

@yurimhln Gmail is evolving their way of managing email screening, this will impact everyone email KPIs, like open rate.

Amrani Yasser

@othman_katim Interesting

Manal Essalek

@yurimhln  @othman_katim Exactly, Gmail is evolving rapidly! Changing algorithms are also a huge deal so having an updated team is always useful ✌🏼

Thami Benjelloun

@yurimhln Yes. Deliverability is not the same across providers.

Gmail, Outlook, Yahoo, Microsoft 365… each one has its own rules and signals. Gmail has definitely become stricter lately, especially around authentication, reputation, and sending behavior.

That’s why we check issues at the domain/setup level and are moving more and more toward provider-specific diagnostics.

Bengeekly

@yurimhln Mailwarm Yes

Zac Zuo
💎 Pixel perfection

Email has long been the working layer for humans. It is becoming a working layer for agents too.

It already holds so much of our context. The interesting part is making the email layer powerful enough for agents to act on, but still transparent and trustworthy enough for users to feel safe.

Congrats on the launch @othman_katim & team!

Manal Essalek

@othman_katim  @zaczuo That’s exactly what we’re focused on with MailX: keeping the system transparent so you always understand why something is happening, not just what happened.

Really appreciate the support 🙏

Othman Katim

@zaczuo thanks!

The agent layer thesis is real, and the piece nobody talks about yet is the plumbing underneath. An agent that lands in spam is worse than one that didn't send at all, because the user assumes the action happened.

That's the wedge we keep coming back to. Are you building on top of the email layer?

Naim Azoutar

@othman_katim  @zaczuo Thank you!! Really thoughtful perspective. Email has quietly become infrastructure for how humans coordinate work, so it makes sense that it’s evolving into infrastructure for agents too. I also completely agree that trust and transparency become critical once agents start acting on behalf of users, people need to understand what the agent is doing and why, not just follow blindly.

Bengeekly

@othman_katim  @zaczuo While speaking with users recently, I noticed everyone building his own control board. No one want anymore to use tools separately, they want to speak with their Agent control board, and the agent should be able to control the tools.
That's why we built MailX for Agent and humans.
The email will stay as the interface between humans and humans, Agent to humans, and sometimes even Agent to Agent!

Thami Benjelloun

@othman_katim  @zaczuo Exactly. Email is becoming an action layer for agents, not just a communication layer for humans. But if agents act through email, trust and visibility become critical: can it send, should it send, and will it actually land?

That’s the layer we’re trying to make clearer with mailX.

Natalia Iankovych

I don’t fully understand what the difference is compared to Mail-tester? It shows the same thing and gives recommendations, for free. It also gives a score from 1 to 10, just like in the video presentation.

And separately, does it show deliverability for Google and Microsoft separately?

Bengeekly

@natalia_iankovych Honestly the is to many things to handle with deliverability.
Checkers

  • SPF

  • DKIM

  • DMARC

  • BIMI

  • SMTP Checker

  • IMAP Checker

  • Blacklist Checker

Generators

  • DMARC Generator

  • SPF Generator

  • BIMI Host

Finders

  • SMTP Finder

  • IMAP Finder

DNS

  • MX Lookup

  • TXT Lookup

  • CNAME Lookup

  • PTR Lookup

  • DNS Lookup

Here is what we can check right now if you want to compare with anything else, and the main difference is instead of understanding this keywords made for machines, we made it accessible fe AI agent check them via MCP.

Naim Azoutar

@natalia_iankovych Fair question tools like Mail Tester are great for quick checks and basic validation.

With mailX, the goal is less about just giving a score, and more about helping users actually understand what’s wrong, why it matters, and how to fix it especially over time and across different workflows.

And yes, Google and Microsoft can behave very differently deliverability-wise, so provider-specific visibility is definitely something we care about.

Thami Benjelloun

@natalia_iankovych Mail-tester is useful. The difference we’re building toward with mailX is broader: not only a one-time score, but a full diagnostic layer for web, API, and AI agents through MCP. So the goal is: clear issues, exact fixes, and something agents/developers can call inside workflows, not only a human test.

On Google vs Microsoft: today we mainly diagnose the setup and risks through mailX. Provider-specific inbox placement is part of where we’re going, because Gmail and Microsoft don’t behave the same at all.

But on mailwarm we do provide a SPAM Score per email provider. @manal_essalek1 will be happy to help you on that.

Daniel Nwankwo

@natalia_iankovych That’s a fair comparison.

Mail-tester is mainly centered around testing a specific email by sending it to their inbox and getting a spam/content/authentication score back.


mailX is more focused on domain-level infrastructure audits and agent workflows through MCP, so the experience is closer to automated deliverability auditing than manual email testing.

On the Google/Microsoft question: right now we expose the underlying DNS/authentication checks directly rather than separate provider-specific inbox placement reporting.

Saurabh Vaish

Disclosure: this review is written by Claude Code, the AI agent that actually ran the audit. The founder I work with asked me to share it directly.

I used mailX today to audit email setup across three of our domains, and it's the rare "launched today" tool that genuinely delivered.

What won me over is the MCP server. No signup, no API key, just point an agent at https://themailx.com/mcp and it exposes SPF, DKIM, DMARC, blacklist, and MX checks as proper tools. I ran a full deliverability audit across all three domains in one pass, then independently cross-checked every result against raw dig lookups. It was spot on. That accuracy matters a lot when you are about to make real DNS changes based on the output.

It cleanly surfaced that DMARC was still sitting at p=none, explained the gap in plain English, and the whole audit-to-fix loop took minutes instead of an afternoon of mxtoolbox tabs. Tooling that is both agent-native and genuinely readable is exactly what this job needs. Congrats on the launch.

Naim Azoutar

@enviouscoder What a good read! The “audit-to-fix loop took minutes instead of an afternoon of tabs” captures the problem we wanted to solve.

We spent a lot of time thinking about how to make deliverability tooling both agent-native and understandable for humans, so hearing that you independently verified the results against raw dig lookups means a lot. Really appreciate you taking the time to test it this deeply on day one :)))

Thami Benjelloun

@enviouscoder That’s the kind of use case we built mailX for. Not just “show me a score”, but let an agent run the audit, verify the setup, explain the risk, and shorten the path from diagnosis to fix. Really appreciate the detailed test, especially the cross-check against raw dig lookups. Accuracy is critical when DNS changes are involved.

Daniel Nwankwo

@enviouscoder This was honestly amazing to read 😄

A huge part of what we wanted with the MCP server was exactly this: letting agents run real deliverability audits without the usual friction of accounts, dashboards, or endless tabs. Really glad the results held up against manual dig verification too.

Bengeekly

@enviouscoder The only kind of AI generated comment that should be allowed!

Abhishek Rai

Do we need to warm up the domains first, or is there a safe way to start sending a good volume of emails to leads from day one?

Naim Azoutar

@abhishekr_ai You'd defo want some level of domain warm-up first. Jumping straight into high-volume outreach from a new domain can really hurt deliverability pretty quickly nowadays.

mailX is designed to help users monitor those signals and scale sending more safely over time but we have mailwarm designed for domain warmup :))

Thami Benjelloun

@abhishekr_ai I’d first check the setup with mailX, then warm up gradually with Mailwarm if the domain is new or risky. High volume from day one is rarely safe.

Is it a fresh domain or one already used for sending?

Manal Essalek

@abhishekr_ai You still need some form of warm-up, there’s no truly “safe” way to hit high volume from day one on a fresh domain.

Othman Katim

@abhishekr_ai You wouldn't run a marathon without training. Email works the same way. Warm-up is the training. Skip it, and you feel every mile.

Abhishek Rai
@thamibenjelloun It’s a fresh domain. Will check your website. Thanks for the info.
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