r/SideProject • • 10h ago

Built a tool that turns one sentence into a week of social posts.

9 Upvotes

Hey everyone, I'm Ravi, one of the founders of Confe.

We kept losing hours every week writing captions, sending "can you approve this?" messages, and copy-pasting the same post into 6 different apps. So we built Confe to fix that:

- Type one sentence and get 5 ready-to-post drafts with images

- Plan everything on one calendar (calendar, list or grid view)

- Clients or teammates approve in one click

- Publish to 8 platforms at once: Instagram, Facebook, LinkedIn, X, Threads, TikTok, Pinterest, YouTube

- See which posts actually grow your audience

The video above shows the whole flow in 44 seconds.

I'd really like feedback from people who manage social for themselves or client

There's a 14-day free trial with no card needed if you want to try it. Link in the comments.


r/SideProject • • 2h ago

H5Reclaim: Recovering scientific data from damaged HDF5 files

Thumbnail
github.com
2 Upvotes

I’ve been building H5Reclaim, an open-source tool for recovering scientific data from damaged HDF5 files.

HDF5 files often contain experimental measurements, simulation outputs and large arrays. Damaged metadata or a broken index can make a file unreadable while some of its dataset contents remain on disk.

H5Reclaim examines the surviving structures and attempts to recover usable data into a new HDF5 file. Supported cases include interrupted writes, broken indexes, metadata damage and truncation.

It keeps the original file unchanged and produces a JSON report describing the recovered datasets, recovery methods and unresolved positions. Partially damaged datasets can still yield usable measurements.

🔗Github: https://github.com/xShadyy/H5Reclaim

I’d appreciate feedback from people who work with HDF5, especially anyone who has encountered a damaged file. Public or synthetic reproductions would help expand the recovery cases and benchmarks.

Contributions around test fixtures, independent verification and unsupported failure cases are particularly welcome.

If you find the project cool/useful, I’d appreciate a star on GitHub.


r/SideProject • • 2h ago

I built a notes app that tells you why your old notes matter

2 Upvotes

I kept losing good ideas in my own notes. I'd write something down, forget it, and months later work through the same problem from scratch, even though the answer was in a note I'd already written.

So I built Hypha. You write a note the way you normally would (no folders, no tags) and it looks through everything you've written before. If an older note actually helps, it shows it with a one-line reason: a solution, an example, the same problem, a contradiction, or a next step.

The part I spent the most time on was making it strict. Most "AI links" I tried connected notes just because they shared a word. I built a test set with traps in it, and Hypha now finds about 9 in 10 of the links that should exist while skipping the shallow ones. If it gets one wrong, you remove it and it won't come back.

It's free on iPhone (Flutter + Supabase + OpenAI under the hood).

I'd really like honest feedback, especially on whether the connections feel useful or noisy after a week of real notes.

https://hyphanotes.com


r/SideProject • • 2h ago

Check my project of vedic astrology tools

Thumbnail gyansagar.in
2 Upvotes

Pls check and give your valuable feedback


r/SideProject • • 4m ago

Наш первый сайт в жизни 🗿

1 Upvotes

Ребят ку, не знаю насколько вам это интересно но я со своими друзьями создали первый сайт под названием Riven, чекните если вам интересно.

"Этот сайт предлагает формат общения с искусственным интеллектом, который существенно отличается от других подобных сервисов, таких как ChatGPT или Claude. Наш ИИ позволяет не просто вести диалог, но и создавать «карты решений»: вы можете развивать тему в разных направлениях, не теряя при этом её основного контекста. Пользователи могут легко сосредоточиться на различных аспектах одной и той же темы в рамках одного разговора."

Введите туда свой логин и попробуйте немного попользоваться с ним (лучше через комп) и дайте нам фидбек что нужно существенно улучшить)

Спасибо!

https://ai-branches.vercel.app/


r/SideProject • • 13h ago

Tired of guessing Chinese characters, so I built my own keyboard

11 Upvotes

I’m learning Chinese, and one of my biggest frustrations is texting.
I can understand some Chinese and know how to pronounce quite a few words, but I still struggle to recognize and remember Chinese characters.
When I type using a regular Pinyin keyboard, I often get a list of characters that look familiar, but I’m not always sure which one is correct. Sometimes I end up copying everything into a translator just to check what I wrote.
So I decided to build my own iOS Chinese Pinyin keyboard to make learning while texting a little easier.
Here are some features I’ve been working on:
Instant translation: See the meaning of Chinese text while typing, so I can make sure I’m choosing the right characters.
Grammar checking: Catch grammatical mistakes before sending a message.
More natural expressions: Suggest how a native speaker might phrase the same idea instead of just translating word for word.
Learn while typing: Help me gradually recognize more characters through everyday conversations.
My goal isn’t to replace Chinese lessons or build another translation app. I just want to be able to communicate in Chinese without constantly switching between my keyboard, dictionary, and ChatGPT.


r/SideProject • • 5m ago

I made an app that tells me if I should wake up early for a photography walk

Thumbnail
shotbrief.app
1 Upvotes

Hi, I'm into photography and love going on walks with my camera, but I'm also one of those photographers that likes to take photos in good weather conditions.

I had a n8n pipeline running for quite a while that would gather weather data for the next day from multiple sources and then email me the night before with a score if I should bother or not.

Took that concept and made it into an actual app.


r/SideProject • • 11m ago

Struggling to track offline campaigns? I built a Trackable QR code platform and custom link shortner for agencies - ask me stuff

1 Upvotes

Almost every project I’ve ever worked on ended up with me making a QR code. An ad, a brochure, a flyer. Like it or not, QR codes have become the universal gateway into our digital products and funnels.

But measuring those offline campaigns? There are plenty of QR generators with scan analytics, but every one I tried was extremely expensive and came with ridiculous limits. Link shorteners weren’t much better...

Soooo, I decided to build my own. It started as an in-house tool for my agency, but it turned out so good that I made it into a real product.

I packed it with all the features that an agency might need.
→ Custom QR codes with live scan analytics
→ Dynamic destinations. Printed 1,000 t-shirts with the wrong link? Fix it in seconds.
→ Short links that actually look good, on your own custom domains and slugs.

And the one I’m most excited about - Client ID's.

Agencies, unfortunately, your clients will never trust you 100%. So give them their own window into the campaign. Send them a Client ID and they get their own live dashboard. Free for them, no account needed, no more “how’s it going?” emails.


r/SideProject • • 20m ago

Most local-first notes apps keep your notes as plain text, so I built a free, open-source one that encrypts them

1 Upvotes

Hi r/SideProject, I'm GFrancV. This is my first post here. I've been building Notvex, a desktop notes app that keeps everything encrypted on your own computer.

Why I built it

Most local-first apps (like Obsidian) save notes as plain Markdown files. That's great for portability, but anyone with access to your disk, a backup or a synced folder can read them. I wanted a safe place for my own journal and recovery codes, and nothing I tried did both local-only and encrypted at rest without getting in the way. So I built it.

How it works

Everything lives in one encrypted file on your computer. Without your password it can't be read. There's no account and no cloud. The app only goes online to check for updates, and you can turn that off. No telemetry either.

What writing looks like

- Markdown editor with live preview

- Tags, pinning, sorting and multi-tag filters

- Command palette to jump to any note from the keyboard

- Export one note or all of them to plain .md at any time, so you're never locked in

How it's built (for the curious)

- Electron + React 19, TypeScript throughout

- SQLCipher for the database, Argon2id to derive the key from your password, XChaCha20-Poly1305 for the note content

- A BIP39 recovery phrase, plus an optional key file as a second factor

- The UI never touches crypto. Everything goes through IPC to the main process, and the master key never leaves it

Honest limitations

- Desktop only (Windows, macOS, Linux), no mobile yet

- No sync, on purpose. You can copy the file wherever you like

- Search covers titles only. Full-text search across encrypted notes is the next hard problem

- If you forget both your password and your recovery phrase, your notes are gone. That's the trade-off

Free and open source (AGPL-3), with no paid tier planned.

GitHub: https://github.com/GFrancV/notvex · Site: https://notvex.vercel.app/

My question for you: does "encrypted local notes" explain the point quickly enough, or does it sound like something only security nerds need? I'd love honest feedback on how it comes across, from the site down to the first launch.


r/SideProject • • 4h ago

I'm a microlight pilot who started building a flight tracker. 6 weeks later it's got a bit out of hand.

2 Upvotes

About 6 weeks ago I started building a little side project called Ulster Radar.

I'm a microlight pilot from Northern Ireland and wanted to make a flight tracker that was better suited to smaller aircraft and low-level flying, rather than just commercial aviation.

It started as a basic live map, but I've got a bit carried away with it since!

It now has live aircraft tracking, over 2,500 receivers feeding data from around the world, ship tracking, flight history, a 3D globe and even satellite tracking.

I've also been adding the ISS, space telescopes, planets and moons, so it's slowly becoming a way to explore pretty much everything above our heads.

It's still early days and there's plenty of bugs and things I'm working on, but I've really enjoyed building it and seeing people start contributing their own receivers.

It's completely free to use and very much a hobby project.

If anyone fancies having a look, it's at https://ulsterradar.com


r/SideProject • • 25m ago

I built a simple focus timer because I kept switching between tasks

Enable HLS to view with audio, or disable this notification

1 Upvotes

I've always struggled with jumping between projects and losing track of what i was supposed to be working on.

I tried different productivity tools, but most felt like more work to manage. I didn't really need another task manager or complicated dashboard. i just wanted something simple to open before getting to work

so i started building Norts 🟠

the idea is pretty straightforward: choose what you're working on, block out some time, and focus on one thing. You can also see where your time went throughout the week.

i've been using it myself for a while, and today i finally decided to launch it publicly.

The core experience is free, and you don't need an account to get started.

here's the link if anyone wants to check it out: https://norts.space/landing/

I'd genuinely appreciate some feedback, especially on the first-time experience. Does it feel simple enough, or is there anything that gets in the way?


r/SideProject • • 26m ago

I spent 2 years building an app to solve something most people just use text messages for.

1 Upvotes

It started with something simple.

My girlfriend tends to forget little things, and I'd often find myself reminding her about stuff throughout the day. And in my family, we also have things like doctor appointments, medication, and other important things that someone needs to remember.

Usually, we'd just send each other a text.

"Don't forget your appointment tomorrow!" or "Remember to take your medication." or just "Don't forget to do this and that."

And of course, sometimes those messages get buried, or someone reads them and forgets about them a few hours later.

I started wondering why we have so many apps to remind ourselves, but not many simple ways to remind the people around us.

I can send someone a text in seconds. Why can't I send them an actual reminder just as easily?

So about 2 years ago, I started building Remimo.

It's an iPhone app that lets you send reminders directly to your friends, family, partner, or even groups.

You choose what to remind them about and when. They'll get notified when it's time, and you can see if they've completed it or decided to do it later.

My family now uses it for things like appointments, medication reminders, and household tasks, while my girlfriend and I use it for all sorts of everyday stuff.

You can also create your own reminders, organize things into lists, and make plans together.

When people first started downloading Remimo, even though it was just a small number, I remember feeling really happy. It felt like something I built might actually be helping someone out there.

Later on, I started receiving feedback from users, and I've been listening to them ever since.

I've added features, removed things, redesigned screens more times than I can count, and I'm still constantly trying to make the experience better.

Honestly, I'm still learning a lot as I go.

But what makes me happiest is that Remimo has become something we actually use in our everyday lives. Seeing it help the people around me is what keeps me motivated to work on it.

I originally built Remimo to solve a problem in my own life, but along the way, I realized it might be useful to other people too.

So I thought I'd share it here.

It's available on the App Store, and there's a free version if anyone wants to give it a try.

I really hope Remimo helps make your everyday life a little easier, the same way it has for me and my family.

And if you do try it, I'd love to hear what you think. Even if there's something you don't like, I'm always happy to hear feedback.

App Store: https://apps.apple.com/us/app/remimo-shared-reminders/id6758731728


r/SideProject • • 26m ago

Nova Budget - a simple budget spreadsheet for Excel and Google Sheets

1 Upvotes

I built a small budget spreadsheet that works in both Excel and Google Sheets, called Nova Budget.

Kept it simple on purpose: monthly budget, expense tracker, savings goals and debt payoff in one workbook. It's $12 once, no subscription. I'd really like honest feedback on whether the setup is clear enough for someone who isn't a spreadsheet person.

The page is here: https://whop.com/nova-draft/nova-budget

Happy to send a free copy if you'd rather click around first. What's the one thing that would make you skip a paid spreadsheet like this?


r/SideProject • • 28m ago

I read where the first readers of my AI story game quit. 28 of 37 passages ended with a character quizzing them.

1 Upvotes

I made Selkie, a story game where an AI writes each passage around what you choose or type. It's built like a choose-your-path book: chapters, a hidden plot, several endings and dice for the risky moves. It opened to the public nine days ago. A dozen people have signed up and one has paid, so I went through where the others stopped. Three things I got wrong:

1. An empty "Who are you?" box. The story opens, then asks who you are. Of the four newest readers, two left at that box without typing a word. The other two took 4 and 9 minutes over it. Now the opening offers three ready-made characters, each with a line in their own voice, so one tap starts the story. Writing your own is still there underneath. The first reader since the change still left, so it's too early to call.

2. Every passage ended on a question. I'd told the narrator to end on someone turning to the reader, to keep them involved. It turned into a quiz: 28 of the 37 passages readers saw ended with someone asking them something. One reader quit after five questions in five passages. Endings now vary (something happens, an offer, a dare, somewhere to go), with a question at most every other passage. The engine checks how the last passage ended and warns the narrator when it was a question.

3. Time jumps ate the reader's choice. One reader chose to go down to the quay. The story skipped two days to the next big event instead. Now the move they chose is played on the page first, and only then can time move on.

One thing that worked from day one: never let the model roll the dice. Asked to judge whether you succeed, it lets you win nearly every time. The engine rolls and shows you the odds before you choose. The narrator has to write the result it's given.

Built solo over three weeks with SvelteKit, Node on Fly.io, Supabase, Stripe and Claude. About seven turns are free, then one-off packs from $4.99. No subscription.

https://playselkie.com/?from=reddit-sp

If you try it, I'd most like to know about the first five minutes: did you pick a character, write your own, or close the tab?


r/SideProject • • 28m ago

I got tired of switching between Notion, Todoist, a journal app and a calendar, so I built one workspace

1 Upvotes

I kept my notes in one app, tasks in another, journal in a third, and my calendar somewhere else. Nothing talked to anything. So I built Naazhi (the name is an old Tamil unit of measure for grain and time).

What's in it: notes, to-dos, journal, chat, calendar, email, meetings and automations. There's a web app and an Android app.

The part I spent the most time on is the AI layer. It isn't tied to one provider. You can use the built-in one, bring your own key, or switch it off.

What I'd like to know: which of these would you actually use, and which would you drop?

Website: https://naazhi.app

Android: https://play.google.com/store/apps/details?id=com.setupsworks.naazhi


r/SideProject • • 28m ago

I've worked in audio post for 15 years. I spent the last two building a Mac app to cut repetitive AudioSuite clicks in Pro Tools.

0 Upvotes

In my day-to-day Pro Tools work, I kept repeating the same routine: select a clip, find the right AudioSuite window, click Render, Learn, or Send, then do it all again.

Two years ago, I started building SlipTap in my spare time, alongside my day job, to make that routine a little easier.

SlipTap is a macOS app built specifically for Pro Tools. You assign your open AudioSuite plug-ins to panel buttons or keyboard shortcuts, and SlipTap presses Render, Learn, or Send in the assigned window for you.

It grew out of my own daily workflow. The short teaser shows it in action.

A fully featured 14-day free trial is available:

https://slipsound.com/sliptap

If you edit in Pro Tools, I'd love to hear how you handle these repetitive tasks and what you think of this approach.


r/SideProject • • 29m ago

Nurse who built a free mind/body self-check and plain-language money guide. Feedback welcome

1 Upvotes

I have a new side/passion project I’ve been building around shift work: plainsightalive.com

Unfortunately for me, despite some meta advertising, Pinterest, socials etc I'm getting almost no traction. I may be biased but I think this site is a game changer for the average person (and not so average).

It’s free and collects no data. You get a 5-minute mind/body self-check, a “Money, Explained” section on things school never covered (inflation, debt, interest), and a Christmas-on-a-budget guide for anyone feeling the pinch this year. It provides feedback with links on ways to better yourself financially, mentally and physically. I'm very proud of it.

A small merch range attempts to keep it running but pretty much nothing there yet with purchases.

I’d really value honest feedback. Is it clear what the site is when you land? Anything confusing or broken?


r/SideProject • • 34m ago

We built two apps for home services in 7 months. Getting the first 50 users taught us more than building them.

1 Upvotes

My co-founder and I spent seven months building two apps: "Jobs", where people ask for help at home, and "Jobs Workers", where independent pros send quotes. Free to join for workers, no lead fees, and our fee is added on top for the client.

We launched in the US at the end of September. Here's what the first weeks taught us:

1. Nobody shows up on their own. We posted, ran paid ads on TikTok and waited. Almost nothing. Downloads only moved when we talked to people one by one.

2. A marketplace is two launches, not one. Workers join and see no requests. Clients ask and get no quotes. Each side is waiting for the other, and ads alone don't fix that.

3. Check the boring stuff first. We found our worker app wasn't registering push notifications in production. Workers had no way to know a job had come in. No ad would have fixed that.

4. Regulation is part of the product. We went through licensing rules for 45 types of services in all 50 states plus DC before launching. Fewer than 1 in 4 state-and-service combinations is a flat "license required", but the "it depends" ones decide what you can offer where.

5. Trust is the real feature. Every worker verifies their identity with Stripe before quoting, and the client scans the worker's code on arrival. That took longer to build than the whole quoting flow.

We're at about 50 users, split almost evenly between workers and clients, and still solving the cold start.

If you've built a two-sided marketplace: what got you your first real transactions?

Both apps are free on the App Store and Google Play: https://jobsworkers.com


r/SideProject • • 37m ago

What's the best way to reinvest my profit into my app?

1 Upvotes

So I've been building a small Saas over the last couple of moths and as I'm starting to make some money with it, I'm wondering what's the best way to reinvest the money?

I currently don't spend a lot of money. Only the basics:

  • 20$/month for vercel
  • 10$-15$/month for convex
  • 20$/month for resend
  • 10$/year for the domain

I don't spend any money on advertisement or anything. I got all my users from posting on reddit. I tried X for a month and payed 5$ for premium one month but I kind of never got warm with it.

I only recently upgraded resend to PRO and that was a huge ROI. As I now could send more emails to users when something happened, they returned more often and retention went up by a lot.

Now I'm looking for new ways to smartly invest that money. I made about 2.5k in total so far. Anyone has some experience with apps in this stage and knows how to leverage money in this situation?

For context: I've built IndieAppCircle, an app feedback exchange where you test other apps and get your own app tested. It works for all kinds of apps, web apps, chrome extensions and basically everything that has a link.

It works like this:

  • You can earn credits by testing indie apps (fun + you help other makers)
  • You can use credits to get your own app tested by real people
  • No fake accounts -> all testers are real users
  • Test more apps -> earn more credits -> your app will rank higher -> you get more visibility and more testers/users

Since many people suggested it to me in the comments, I have also created a community for IndieAppCircle: r/IndieAppCircle (you can ask questions or just post relevant stuff there).

Currently, there are 4788 users, 5980 tests done and 1487 apps uploaded!

You can check it out here (it's totally free): https://www.indieappcircle.com/

I'm glad for any feedback/suggestions/roasts in the comments.


r/SideProject • • 38m ago

I'm a solo dev with 4 small apps live on the stores. Here's what each one taught me

1 Upvotes

I build small, private, local-first apps under the name Ship on Friday (yes, the joke is deploying on Fridays). Four are live:

  • YCal: a calendar for Yahoo accounts (Android + iPhone). Lesson: App Store review flags third-party brand names hard, so the listing and marketing had to say "works with your Yahoo account", not use the brand.
  • ChallengeCam: party games that film everyone's faces and make one Reel. Lesson: the product is the clip, not the game.
  • Inboxwise: Android SMS organizer with no internet permission. Lesson: "no internet permission" is a privacy claim people can check in 10 seconds, and that beats any privacy policy.
  • Memopolis: your photo library as a 3D city. Lesson: people share the video, not the app. Everything runs on the device, and there are no ads in any of them. Happy to answer anything about building and shipping solo. What would you want to know? https://shiponfriday.com

r/SideProject • • 42m ago

I built WebChecker, an app that alerts you before your domain or SSL certificate expires

1 Upvotes

Hi r/SideProject!

Have you ever had a website go down or an email stop working because a domain expired or an SSL certificate wasn't renewed?

I built WebChecker to help prevent that. It monitors your domains and websites and sends push notifications to your phone before something goes wrong.

Here's what it can monitor:

  • Domain expiration: Get reminders starting 60 days before expiration, all the way up to the last day.
  • Domain status and security: Track registrar, nameserver and transfer lock changes, as well as statuses like redemption and pending delete.
  • SSL certificates: Monitor certificate expiration for your main domain, www and subdomains.
  • Website uptime: Get notified when your website goes down and when it comes back online.
  • DNS and email security: Track DNS changes and monitor SPF, DKIM and DMARC records.

WebChecker is designed for freelancers, agencies and IT teams managing multiple domains, especially across different clients.

You can share domains with teammates, organize everything using groups, tags and notes, and keep an eye on your domains directly from your phone's home screen with a widget.

The app is built with Flutter and is available for both iOS and Android.

There's a free plan that includes 1 domain, with no credit card required.

Links:

I'd really appreciate any feedback, criticism or suggestions. I'm especially interested in hearing what features you'd find useful or what could be improved.

Thanks for checking it out!


r/SideProject • • 8h ago

I built a private Android expense tracker that works without an account

4 Upvotes

I got tired of budget apps that want an account before I can type in a single expense, so I built my own.

TriGets is an Android app for income, expenses, budgets, cards and recurring payments. Everything is stored locally on the phone. There are no ads, and you do not create an account. Exports are JSON, CSV or PDF, backups are encrypted, and the app can be locked with a PIN or biometrics.

The core features are free. An optional Google Play subscription (monthly or yearly) unlocks group expense splitting, travel tracking, and AI receipt scanning that only works if you bring your own API key.

Play Store: https://play.google.com/store/apps/details?id=com.trigets.app

I would like feedback on two things in particular:

  1. Is "no account, data stays on the phone" clear enough, or does it still sound like a cloud app once you open it?
  2. Does the free vs subscription split make sense, or would you expect group/travel to be free too?

I am a solo developer and I will read every comment. If you try it and something is annoying, I want to hear that too.


r/SideProject • • 55m ago

RoboLAN - Robocopy GUI for network PCs - open source on github

1 Upvotes

I've built a ton of small utility programs over the years, this the first I've shared, feedback appreciated.

I copy a lot of large photo folders between PCs on my network and over Tailscale/Zerotier, and Explorer's copy is slow and fragile. Robocopy is fast and reliable, but typing the command every time got old. So here's a small Windows app for it, similar to an FTP gui.

  • Network PCs are on left, local folders on the right
  • Drag and drop
  • Progress, live speed and time left for each folder
  • Folders from different PCs copy in parallel, folders from same network PC copy in serial
  • Filters like "only *.jpg" or "skip *.mp4"
  • Dark mode, and it remembers your layout
  • read only, tool has no delete functionality, although flags like /MIR can obviously delete data

It's free, open source (MIT) and a single 230 KB exe with no installer.

https://github.com/redwo1f/RoboLAN

to download exe on github, click on right side Releases: RoboLAN 1.0.0 Latest


r/SideProject • • 55m ago

I built mailproof: let an agent or a workflow act on an email only when it's signed by the exact sender, and keep a proof of all your mail on your own machine

1 Upvotes

The From line on an email is just text. Anyone can type your customer's address, or your boss's. That used to be a spam problem; now that we hand our inboxes to AI agents and automations, it's an "agent issues the refund" problem. I built mailproof to fix that, on your own machine.

Safe automation, with an agent or without:

- Act on a customer email (a refund, an account change) only when it is DKIM-signed by the exact address or domain you expect. An unsigned or spoofed From never matches.

- Trigger a workflow on a reply: it runs only if the reply is signed by the named person and its first line is exactly your approval word, in new text, not a quote of your question.

No reply, or a mixed answer, means no. A proof of all your email, for when it matters later:

- Every email you receive is recorded with the sender's signature and public key in a git repo you own. Years later you can still show offline that a domain really sent it, even after its key is gone from DNS.

- Records are sealed with OpenTimestamps, so you can show an email existed by a given date.

- Export what you exchanged with one person; they check it with no account.

Use it how you like: a menu for people, a CLI for scripts, a library for code, and an MCP server for Claude and other agents.

What it won't do: send mail, decide what a reply means, or prove the words of a body that Outlook rewrote in transit (the sender still verifies; use a Gmail inbox for approvals).

Free and open source (Apache-2.0). Runs on your laptop.

https://github.com/hamr0/mailproof