VEVendan·Nov 18, 2024
The website is out of date, last release was actually in may (like smtp4dev) https://github.com/sj26/mailcatcher/releases/tag/v0.10.0
In MailCatcher runs a super simple SMTP serversj26
mailcatcher
Ruby2020–2024
sj26 / mailcatcher
mailcatcher
Catches mail and serves it through a dream.
4Distinct people
5Mentions
0Explicit recommenders
6.8KGitHub stars
What to know before exploring
What it is
Catches mail and serves it through a dream.
GitHub
Where it is used
No documented product use has been verified yet.
What people are saying
No recommendation phrase was found in the indexed comments.
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Also in these discussions
- maildev/maildev · linked in 2 of the same discussions
- mailhog/mailhog · linked in 2 of the same discussions
Mentioned in the same Hacker News threads. That is not proof they are substitutes.
This week on Hacker News
Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 3:56:07 PM UTC.
No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.
Mentions over time
HN mentions by year5 dated mentions
Observed mentions: 2020-01-22 10:25:51 UTC to 2024-11-18 23:54:27 UTC.
Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.
View mention counts and date ranges
| Period | Start (UTC) | End (exclusive, UTC) | Mentions | Submissions | Comments |
|---|---|---|---|---|---|
| 2020 | 2020-01-01 00:00:00 UTC | 2021-01-01 00:00:00 UTC | 1 | 0 | 1 |
| 2021 | 2021-01-01 00:00:00 UTC | 2022-01-01 00:00:00 UTC | 1 | 0 | 1 |
| 2022 | 2022-01-01 00:00:00 UTC | 2023-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2023 | 2023-01-01 00:00:00 UTC | 2024-01-01 00:00:00 UTC | 1 | 0 | 1 |
| 2024 | 2024-01-01 00:00:00 UTC | 2025-01-01 00:00:00 UTC | 2 | 0 | 2 |
What Hacker News says
5 sourcesA few others (last I looked, mailhog was the best option IMHO):
- https://github.com/maildev/maildev
- https://github.com/Nilhcem/FakeSMTP
- https://gitlab.com/markbeeson/maildrop
- https://github.com/sj26/mailcatcher
In Show HN: A fake SMTP server for software integration testinghey HN, I recently published an article going deep into email previewing (in Ruby on Rails, but I think it's relevant beyond Rails).
MailCatcher (https://github.com/sj26/mailcatcher) and MailHog (https://github.com/mailhog/MailHog) are super handy and easy to run locally. Both spin up an SMTP server which you can direct mail to, and give you a nice web interface to browse mail and preview it.
Happy to answer any question! thanks, harrison
In Preview emails with letter_opener, MailCatcher and MailHogWith the advent of easy to use docker containers, this is really easy to do for most backing services, right on your machine during tests (and in CI).
If all your app needs is rabbitmq (or some queue), redis, and postgres you can run all of them in the background and give out databases/exchanges to your app as you see fit. This also does something interesting -- it turns you away from tools that don't do badly in containerized environments or who are hard to set up, which is a benefit in my mind. It also turns you away from proprietary cloud solutions that you can't run yourself (which isn't always possible but meh).
I trust my E2E tests a lot more when they're not built on mocking. I'm almost tempted to say that mocking is pointless in this world -- just test the real thing.
[EDIT] Since most people will know how to run redis/postgres/ra
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bbitmq easily, one of the high value things is smtp testing. Here are a few projectsfor that:
- https://github.com/sj26/mailcatcher (https://mailcatcher.me)
- https://github.com/mailhog/MailHog
- https://github.com/maildev/maildev (http://maildev.github.io/maildev/)
- https://github.com/remko/smtp-http-proxy (this is more for turning SMTP into HTTP but it's cool)
- https://github.com/flashmob/go-guerrilla
Remember, for a lot of these projects don't be worried if you don't see updates for years -- once you've written a reasonably working SMTP server, it may not need to change much.
I might take one of these and try to build a MailTrap[0] competitor eventually. $10/month is twice the cost of a digital ocean droplet running one of these pieces of software (and I know that I can run the instances for even cheaper).
[0]: https://mailtrap.io/pricing/
Is there a specific reason you haven't replaced the Vagrant stuff with a container-based approach? You can also do stuff like using the lxc backend[0] for Vagrant if that's more your speed. While containers aren't strictly better, they are certainly lighter weight and quicker to spin up/tear down, though performance characteristics and OS settings/etc can definitely differ.
I've found linux containers to be fantastic for both replicating pieces of the environment and making your e2e tests a little more offical. Running postgres itself (migrating it like you would your real app, inserting data like the app would, then tearing it all down in seconds), apps like mailcatcher[1][2] and actually letting your app send mail (this way you don't even need a local/log-only implementation), running redis locally, and replicating S3 with a project lik
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e minio[3] is very easy and fast.
You can take this even further also by building a way to completely spin up your production environment to a certain point in time locally -- though all the resources for the ecosystem of apps may not be on the same VM image (otherwise you could just snapshot and technically go to the point in time), if you can assemble the state and the backups, you can hook them all up to the containers running locally (or in a VM running locally to be fair) and get an approximation of your entire system.
Of course, it is somewhat less true-to-production (given that production is you running a VM), but you can remove that barrier with things like linuxkit[4].
[0]: https://github.com/fgrehm/vagrant-lxc
[1]: https://mailcatcher.me
[2]: https://github.com/sj26/mailcatcher
[3]: https://www.minio.io/
[4]: https://github.com/linuxkit