{"id":101509,"title":"mailX by mailwarm - Instant deliverability diagnostics for AI agents \u0026 humans.","tagline":"mailX tells you why emails go to spam and how to fix it, via web, API, and MCP.","body":"Hey YC\n\nI’m [Amine](https://www.linkedin.com/in/bengeekly/), CTO of Mailwarm (YC S20) and today we’re launching [mailX](https://themailx.com).\\\n[Thami](https://www.linkedin.com/in/thami-benjelloun/) is the CEO, [Othman](https://www.linkedin.com/in/othmankatim/) is our Head of deliverability and we are ready to help you with all your email deliverability problems.\n\nWe’ve been working on email deliverability since 2020. Mailwarm started as an email warmup tool and became [#1 Product of the Day](https://www.producthunt.com/products/mailwarm) on Product Hunt. Since then, we’ve helped thousands of teams improve sender reputation and inbox placement.\n\nToday, we’re building a broader email deliverability ecosystem:\n\n* **Mailwarm** helps teams build sender reputation through real inbox interactions.\n* **mailX** helps humans and AI agents diagnose deliverability issues.\n* **MailAdept** helps companies fix and monitor deliverability continuously with AI agents and human experts.\n\nToday we’re launching [mailX](https://themailx.com).\n\n![uploaded image](/media/?type=post\u0026id=101509\u0026key=user_uploads/422675/836ee2bb-f82d-4b97-9c90-c77c6d0d62f0)\n\n---\n\n## TL;DR\n\n**mailX tells you why your emails go to spam and how to fix it.**\\\nYou can run a deliverability check from the web, use it through a JSON API, or plug it directly into AI agents through MCP.\n\nNo signup.\\\nNo API key.\\\nFree to use.\n\nTry it here: [**https://themailx.com**](https://themailx.com)\\\nMCP endpoint: [**https://themailx.com/mcp**](https://themailx.com/mcp)\n\n---\n\nYou can also book a call with one of our email deliverability expert [HERE](https://calendly.com/mailwarmsessions/mailx).\n\n## 🚨 The Problem\n\nEmail deliverability is technical, your marketing team can’t handle it.\n\nEmail is still one of the most important growth channels for startups.\n\nFounders use it for cold outreach.\\\nSales teams use it for outbound.\\\nMarketing teams use it for campaigns.\\\nProducts use it for onboarding, activation, and transactional emails.\n\nBut when emails start going to spam, most teams don’t really know why.\n\nThey check random tools.\\\nThey look at raw DNS records.\\\nThey ask ChatGPT.\\\nThey change things blindly.\\\nThey wait and hope inbox placement improves.\n\nThe problem is not only that deliverability is technical.\n\nThe real problem is that most tools show data, but don’t explain what matters or what to fix.\n\nAnd now, with AI agents sending emails, monitoring systems, and managing workflows, this problem gets bigger.\n\nAgents need access to live deliverability tools too.\n\n---\n\n## 💡Our Solution\n\n**mailX is a free deliverability diagnostic platform for humans and AI agents.**\n\nWith mailX, you can analyze a domain in seconds and get a clear report showing:\n\n* What is working\n* What is broken\n* Why it matters\n* What to fix next\n\nThe web app gives founders, marketers, sales teams, and developers a simple way to understand why emails may go to spam.\n\nThe API and MCP server make the same tools available to AI agents and developer workflows.\n\nSo instead of copying DNS records into different tools, your agent can directly check email authentication, blacklist status, mail server configuration, and deliverability signals.\n\n---\n\n## ⏳How it works\n\n1. Enter a domain on [**themailx.com**](http://themailx.com)\n2. mailX runs a live deliverability audit\n3. You get clear issues, explanations, and fixes\n4. Developers can use the JSON API\n5. AI agents can use the MCP endpoint directly\n\nThe best part is that you can lets you AI Agent fix your deliverability or directly integrate it to your Claude or ChatGPT.\n\nHere’s a quick demo of mailX:\\\n\u003chttps://www.youtube.com/watch?v=YWmV7-wthQI\u003e\n\nIn the demo, we show:\n\n* Running a domain audit\n* Getting clear fixes\n* Using the MCP/API layer for AI agents and developers\n\nWe currently support checks and tools for email authentication, DNS records, blacklist status, mail server configuration, and record generation.\n\n---\n\n## Why now?\n\nEmail deliverability used to be something only email experts cared about.\n\nToday, every startup relying on outbound, lifecycle emails, AI SDRs, or automated email workflows needs to understand it.\n\nAt the same time, AI agents are becoming part of the stack.\n\nBut agents need tools.\\\nThey need live data.\\\nThey need safe, structured ways to diagnose and act.\n\nThat’s why we made mailX available through:\n\n* Web app\n* JSON API\n* MCP server\n* Agent skill\n* LLM discovery endpoints\n\nOur belief is simple:\n\n**Email deliverability should be understandable for humans and usable by AI agents.**\n\n![uploaded image](/media/?type=post\u0026id=101509\u0026key=user_uploads/422675/ffc97aad-6864-4525-a89d-0aa1f7890289)\n\n---\n\n## Backstory\n\nIn 2019, we failed a startup after 2 years of work.\n\nAfter that, we decided to test ideas much faster: one launch per week.\n\nEvery launch used the same growth channel: email.\n\nCold emails.\\\nPartnership emails.\\\nLaunch emails.\\\nFollow-ups.\n\nThat’s when we understood something obvious: If your emails don’t land in the inbox, nothing else matters.\n\nThat led us to build Mailwarm in 2020.\n\nAfter years helping thousands of teams improve deliverability, we kept seeing the same pattern: People don’t know why they land in spam.\\\nAnd even when they see the data, they don’t know what to fix.\n\nmailX is our answer to that.\n\n---\n\n---\n\n## 🙏 Our Ask\n\nWe’d love your feedback from the YC community.\n\nIf you are doing cold email, email marketing, transactional email, or building AI agents that send or monitor emails, try mailX and tell us what is missing.\n\nAlso, if you are building an AI agent or workflow where email deliverability matters, we’d love to talk.\n\nTry mailX: [**https://themailx.com**](https://themailx.com)\\\nBook a call through MailAdept if you want help choosing the right setup: [https://calendly.com/mailwarmsessions/mailx](https://calendly.com/mailwarmsessions/mailx?month=2026-05)","slug":"QPF-mailx-by-mailwarm-instant-deliverability-diagnostics-for-ai-agents-humans","created_at":"2026-05-18T17:10:14.688Z","updated_at":"2026-05-25T06:33:26.526Z","total_vote_count":31,"url":"https://www.ycombinator.com/launches/QPF-mailx-by-mailwarm-instant-deliverability-diagnostics-for-ai-agents-humans","share_image_url":"https://www.ycombinator.com/media/?type=post\u0026id=101509\u0026key=user_uploads/422675/836ee2bb-f82d-4b97-9c90-c77c6d0d62f0","company":{"id":22021,"name":"Mailwarm","slug":"mailwarm","url":"https://www.mailwarm.com","logo":"https://bookface-images.s3.amazonaws.com/small_logos/28e9d8c1afc2f855ecd63f4a8547074fb4563efd.png","batch":"Summer 2020","industry":"B2B","tags":["SaaS","B2B","Marketing","Email"],"search_path":"https://bookface.ycombinator.com/company/22021"}}