I built a service to detect invalid and malicious email addresses
Hello HN, around October last year, I started to work on campaignkit.cc as a side project. It is a service to detect invalid and malicious email addresses. You can upload text files, and use the REST API or direct integration to retrieve a detailed report for each email address. End of March I added Stripe Payments and got my first paying customers via SEM. A coworker suggested starting a Show HN thread, so here we are :) I used golang for the backend since I wanted something lightweight with fast compilation times (coming from scala). For the frontend, I'm using Next.js and TailwindUI. On…
What it does
In the maker’s words, at launch
Hello HN, around October last year, I started to work on campaignkit.cc as a side project. It is a service to detect invalid and malicious email addresses. You can upload text files, and use the REST API or direct integration to retrieve a detailed report for each email address. End of March I added Stripe Payments and got my first paying customers via SEM. A coworker suggested starting a Show HN thread, so here we are :) I used golang for the backend since I wanted something lightweight with fast compilation times (coming from scala). For the frontend, I'm using Next.js and TailwindUI. On the further roadmap, I plan to provide more services around email deliverability. This includes Inbox placement, Backlist monitors and DMARC Analyzer. I’m happy to answer questions, take criticism, and generally hear what you think.
Does the same job
all alternatives →- SHShow HN2011 · tonecheck.com · ▲14
Hi, i was wondering what the HN community thinks of this email tone check application? Do you think this can be done better with open-source? Disclaimer: I am neither a founder or an employee at the company. Just someone who had a similar idea.
- MAMessagify - a private Disqus for web apps. Feedback?2011 · messagify.com · ▲26
Hey HN, I'm a longtime reader and this is my first Show HN (exciting!) It's a collaboration between me and two friends, and we're building this upon another app we made called EmailYak, an API to receive email. We're trying something new and releasing the documentation to an app while we're still building it. We'd love feedback. Do you belong to any of these categories? 1) You've built an app with two distinct groups of users (say, people with cars and those looking for a ride) and they were able to communicate with each other. Did you expose personal email addresses? Did you send…
- IBI built a tool that helps predict HN front page successMay 2026 · wannalaunch.com · ▲26
Hey HN community, I built a tool that helps optimize your post for hitting the first page of Show HN. How it works: I used a Hugging Face dataset of all Hacker News posts from the past 3 years and trained a model that predicts how successful your post might be. There's still a lot of randomness on HN, so nothing is guaranteed, but the tool helps optimize your post for higher odds. A couple of interesting findings: - GitHub repo links work x3 better than regular domains - Open-source tools have a steady virality rate (13.9% - one of the highest) - "I built" outperforms "We built" - Using…
- IMI made email validation tool2025 · verifyemailai.com · ▲7
Hey HN, I’m a solopreneur and have been in the SaaS space for the past 3 years. My last 3 startups failed, and a common challenge in all of them was figuring out how to reach my audience. Recently I started with cold outreach (its a struggle, since I dont have much experience with marketing). I am finding leads mainly using exa.ai websets (web vector search, extremelly good for multiple use cases, recommend checking them out) and then sending them through smartlead. I ran the campaign for the past 30 days and 12-15% emails always bounced. This wasted my email credits & chances of reaching…
- HMHN Mail – A topic-based newsletter service for Hacker News2018 · hnmail.io · ▲27
- IVI've built a REST Test client in my spare time2012 · wcfstorm.com · ▲11
Hi HN,<p>In my spare time (evenings and weekends) I've built 3 products which have been relatively successful even with little advertising (only google ads budgeted at $30 per day). The latest one is WcfStorm.Rest; which is a REST service test client. I built it because I found that the current tools did not have the features I wanted such as, intellisense when working with HTTP headers, syntax highlighting for JSON messages, etc.<p>I'm continually trying to improve these products and would very much love get your feedback. Every suggestion is welcome!<p>(My apologies…
More dev tools this month
the category →



Open-source GTM skills for technical founders
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OpenTrailPaper is open-source bike computer firmware for the LilyGO T5S3 4.7" E-Paper PRO. It supports offline maps, GPX routes, FIT recording and Bluetooth sensors.
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Launched alongside, April 2022
the whole month →- WA
Hi HN community, I’m Zach, founder and CEO of Warp, and am excited to show you Warp, a fast Rust-based terminal that’s easy to use and built for teams. As of today, Warp is in public beta and any Mac user can download it. It works with bash, zsh, and fish. The terminal’s teletype-like interface has made it hard for the CLI to thrive. After 20 years of programming, I still find it hard to copy a command’s output; I always forget how to use `tar`; and I always have to relearn how to move my cursor. To fix fundamental accessibility issues, I believe we need to start innovating on the terminal,…
Dev tools · 2022 · warp.dev
- SS
Life & fun · 2022 · slowsocial.us

- MY
Implement scanyourpdf.com in JavaScript. No backend servers needed.
Life & fun · 2022 · lookscanned.io

