r/sideprojects • • 5h ago

Discussion I made AI crawlers pay per page with HTTP 402 instead of blocking them. People still browse free.

8 Upvotes

AI crawlers (GPTBot, ClaudeBot, PerplexityBot and friends) now fetch a big share of pages on a lot of sites. The options so far have been: let them take everything for free, or block them in robots.txt and disappear from AI answers.

There's a third option now. HTTP has had a status code for this since 1997, 402 Payment Required, and it finally has a working payment scheme (x402: the client signs a USDC payment and retries the same request; it settles in about a second, no accounts or API keys).

So I built a small gateway for it:

You register your site once (free API key, your wallet address, a price like $0.002 a page).

You put ~10 lines in front of your site. There's a Cloudflare Worker version and an Express middleware.

Requests from known AI crawlers get a 402 with your price. A crawler that pays gets the page; the money goes straight to your wallet (the gateway never holds it).

Everyone else, including Googlebot and Bingbot, gets the page as usual, so search ranking doesn't change.

If your site errors, nobody gets charged.

Setup and the snippets: https://aipaygen.com/pay-per-crawl

Honest caveats: crawlers that lie about their user agent won't be caught by this, and most crawlers can't pay yet, so today it mostly works like a block with a price tag on it. But agent frameworks are adding x402 support quickly, and this gives them a way to say yes.

Happy to answer questions about how the 402 flow works.


r/sideprojects • • 8h ago

Showcase: Free(mium) I built a writing platform in a few weeks.

7 Upvotes

I'm a 16-year-old solo developer from India.

Over the past few weeks, I built Lettrim, a writing platform designed for people who want more control over their creative work.

You can create writing projects, experiment with alternate versions, track changes, restore previous revisions, and collaborate with others.

The product is finished and live.

I'm now trying to find my first two paying customers.

My Founder 100 offer is $25 for the first year, paid once, with no automatic renewal.

I'm particularly interested in hearing from novelists, fiction writers, and people working on collaborative writing projects.

Website: https://lettrim.com

I'd appreciate your thoughts, especially if you write regularly.


r/sideprojects • • 4h ago

Showcase: Free(mium) made a free site to learn AI through little games, want blunt feedback

3 Upvotes

I got tired of AI courses that are just 40 min videos so I built Ovrelia. It's free, no signup needed for the tools. There's a hallucination hunt (spot what the AI made up), a prompt lab and a "which AI tool should I use" quiz.
https://ovrelia.vercel.app
Still rough in places tbh. What would make you actually come back to something like this?


r/sideprojects • • 1m ago

Feedback Request I built an iPhone app for filmmakers and content creators to make Log footage easier to watch and share.

Thumbnail
reddit.com
1 Upvotes

r/sideprojects • • 8m ago

Showcase: Purchase Required I built an offline-first 3D Rubik's cube solver, trainer, and speed mat for phones, foldables, tablets, and XR

Thumbnail
reddit.com
1 Upvotes

r/sideprojects • • 12m ago

Feedback Request I built a free browser toolkit for PDFs and photos (no sign-up), looking for honest feedback

Thumbnail
reddit.com
1 Upvotes

r/sideprojects • • 6h ago

Showcase: Prerelease I built a way to give clients AI agents you can actually supervise. Tell me what's wrong with it

Thumbnail
reddit.com
3 Upvotes

r/sideprojects • • 23m ago

Showcase: Open Source 3 years ago I posted my Epic free games newsletter (1000+ subscribers now). I just made a Steam version too!

Thumbnail
steamfreegamesmail.com
1 Upvotes

r/sideprojects • • 45m ago

Showcase: Prerelease I'm building a Mac app to keep an eye on AI activity. Somehow Macbeth and Hemingway got involved.

1 Upvotes

I'm building Angry Porter, a Mac app for keeping track of AI connections and coding-agent activity. The idea is pretty simple: when an agent says it's finished, I'd like a record I can look through.

I love Shakespeare, especially Macbeth. Hemingway is my other favorite author. So I gave Macbeth's porter Hemingway's beard and a new job keeping an eye on who's knocking at the gate. Probably spent more time thinking about the beard than I should have.

The app shows observed AI connections, tool calls routed through MCP connections you configure, and activity reported by supported Claude Code and Codex hooks. The records stay on your Mac.

There are limits. It doesn't decrypt traffic or block connections, and it can't see everything an agent does. What you get depends on which sensors and integrations you set up.

It's a free invited alpha right now, for Apple Silicon Macs running macOS 26 or later. The site has a walkthrough with synthetic demo data and the details on access: https://angryporter.com

If you use coding agents, what do you usually want to check after they say they're finished?


r/sideprojects • • 1h ago

Showcase: Prerelease Got tired of paying to see my own running data, so we built a Strava alternative.

Thumbnail
gallery
1 Upvotes

My brother and I are runners (I'm training for a marathon in Feb). We kept hitting the same wall: the numbers we cared about, like fitness & freshness, grade-adjusted pace and best efforts, are subscription features on Strava.

So we built Inertial, a running app that does the basics with the analytics included.

Upfront on price: the first 1,000 people on the waitlist get their first year free. After that it's a small fee. No ads, no selling your data.

Three questions for you

  1. Is the premium pricing by strava a pain point for you too?

  2. Is "Strava alternative" enough to make you try a new running app, or would you need one thing Strava doesn't have?

  3. Would you move 5+ years of run history over, or is that the dealbreaker?

Waitlist: https://inertial.run/waitlist?src=reddit

Website: https://inertial.run/


r/sideprojects • • 1h ago

Showcase: Free(mium) KGet – Analyze Android Apps, APKs & Security Right on Your Phone

1 Upvotes

Hey everyone!

I wanted to share KGet - Framework Scanner, an Android app that lets you explore how other Android applications are built, inspect APK internals, and perform security analysis directly on your phone.

It started as a framework detection tool and evolved into a more complete Android reverse engineering toolkit.

What you can do with KGet:

  • Framework Detection: Identify Flutter, React Native, Unity, Xamarin, Godot, and other technologies.

  • APK Downloads: Download and inspect APK files from installed applications.

  • DEX & Smali Explorer: Browse classes, methods, Java bytecode, and Smali instructions.

  • Flutter AOT Analysis: Explore Dart structures, embedded strings, and package information inside libapp.so.

  • Native Analysis: Inspect ELF binaries, native libraries, and ARM64 instructions.

  • Security Scanner: Detect potential vulnerabilities, exposed components, insecure configurations, API endpoints, and cryptographic weaknesses using OWASP MASVS-based checks.

APK downloading and framework detection are free and unlimited. Advanced security analysis includes 3 free scans per day, with a Pro option for unlimited scans.

There's also a browser-based version for analyzing APKs without installing the Android app.

I'd love to hear your thoughts and suggestions!

Google Play: https://play.google.com/store/apps/details?id=com.zbd.kget

Web Scanner: https://kgetscan.com


r/sideprojects • • 1h ago

Showcase: Prerelease Built a Mac menu bar app for Sony headphones because Sony only has a phone app

1 Upvotes

I use a WH-1000XM5 at my desk and got annoyed reaching for my phone every time I wanted to switch NC to ambient. So I wrote a native macOS app that talks to the headphones over Bluetooth directly.

What it does: noise cancelling / ambient with level, EQ presets and custom EQ, multipoint (see which device is playing and pull the audio to the Mac), a hotkey to cycle modes, battery alerts. In 1.1 I added profiles that switch automatically, for example during calls or when a certain app is open, plus widgets and Shortcuts support.

Built with Swift and SwiftUI, no backend, no account, no analytics.

Only tested on the XM5 so far. Other Sony models are in there but unverified.

Free TestFlight beta (macOS 14+): https://testflight.apple.com/join/e7S1TqA1

I'm the dev, questions about how it works are welcome in the comments.


r/sideprojects • • 13h ago

Showcase: Free(mium) I made a completely free kettlebell workout app. No ads, no subscriptions, no accounts. Just free.

8 Upvotes

Hello everyone,

My name is Tobias, and I've worked as a software developer for a bunch of years. Between commuting, three small children and everything that follows, my time for workouts is usually pretty limited.

I often found myself grabbing inspiration for workouts and complexes through social media, but found it a pain to keep going back to videos while working out. So I made an app called Complexer to help me out.

It helps me figure out which workout to do based on the time and equipment I have, and then follow through with it. There are ready-made workouts, exercise demonstrations and timers, and you can also add your own workouts. I've been using it myself and really like the result so far, which is why I decided to publish it.

It's free, with no subscriptions, ads or accounts. Your training data stays on your device, and it works offline too. I'm pretty fed up with subscriptions for everything, so I didn't want to add another one.

You can find it here:

https://apps.apple.com/dk/app/complexer/id6824864834

It's only available for iPhone and iPad at the moment.

I'm by far not the most experienced person here when it comes to kettlebells. I just made something that helps me get my workouts done, and hope somebody else can benefit from it too.

A few things I'm looking at next are audio cues so you don't have to keep checking your phone, more of the common workouts and complexes, and a better way to see your progress. I'd also like to add a weekly AMRAP challenge where we all do the same workout and can share our scores, if that's something people would enjoy.

If you give it a try, I'd love to hear what works for you and what could be better.


r/sideprojects • • 1h ago

Showcase: Free(mium) I built a phone finder around one rule: your budget is a ceiling, not a number

Post image
1 Upvotes

Specmob (specmob.com) is a free phone finder. You drag a budget dial and it shows the best phone for that price.

How does the budget dial work?

The dial value is a ceiling. For $500 it shows phones from $450 to $525. The 5% over is there because prices differ by region, and anything over $500 is flagged as over budget instead of hidden. If nothing matches, the floor widens once, to 85%. The ceiling never moves.

Is it free? Yes. I earn a little from affiliate links on buy buttons, and they never change a ranking.

Question for you: do you stick to your phone budget, or does it grow while you shop? And would a 5% tolerance feel fair or like cheating?


r/sideprojects • • 5h ago

Showcase: Free(mium) Bored Hoard - I rebuilt my old StumbleUpon-style discovery site from scratch

2 Upvotes

I recently rebuilt Bored Hoard, a curated discovery site for useful, strange and overlooked websites.

The original version started as a small StumbleUpon-inspired project. An early Reddit post unexpectedly generated a large traffic spike, which exposed several scaling and infrastructure problems. The project was eventually abandoned, but I decided to rebuild it properly.

Live site:

https://boredhoard.com/

What visitors can do:

- Browse curated collections of websites

- Discover something random

- Search by category and topic

- Save websites for later

- Vote for discoveries worth keeping

- Submit their own finds

The goal is to make web discovery feel more intentional and human, rather than another endless algorithmic feed.

The hardest parts were rebuilding the old catalogue, dealing with dead or changed websites, designing a useful editorial model, and making the discovery experience work without requiring users to register.

I would appreciate constructive feedback on:

- Whether the concept is immediately clear

- Whether it feels like a discovery tool or just another directory

- Which part of the experience feels weakest

- What you would improve first

- Whether the visual design fits the idea

This is an active side project and I am still refining it.


r/sideprojects • • 6h ago

Showcase: Open Source Me and a friend created an anti-streaming service

Thumbnail publicinternetsoundstorage.net
2 Upvotes

Hello everyone! Me and a friend have recently been working on publicinternetsoundstorage.net: a website/social media/streaming service/experiment.

The basic idea is very simple:

  1. anyone can upload an mp3 file shorter than 5 minutes once a day

  2. each upload is given a number in the order it was uploaded

  3. anyone can dial a number and listen back to that file

And that's it. There are no accounts, no moderation, and anyone can upload anything completely anonymous.

We've been putting the link everywhere we can and have gotten a pretty crazy range of uploads. Many have been using it as a platform to upload their music/demos, though there are plenty of random sounds and other things you would expect. It's pretty fun to go through some of the numbers and take a listen.

Our current focus is just spreading it around so we can get enough users to make it interesting but we're always looking to improve it. Any feedback is appreciated!


r/sideprojects • • 2h ago

Feedback Request Chess AI in C++

Thumbnail
github.com
1 Upvotes

r/sideprojects • • 2h ago

Question Chess AI in C++

Thumbnail
github.com
1 Upvotes

r/sideprojects • • 2h ago

Showcase: Prerelease We built a scraping API that AI agents connect to directly. Please roast it

1 Upvotes

r/sideprojects • • 2h ago

Feedback Request Looking for 3–5 workflow automation builders to test a lightweight n8n alternative (Free lifetime access)

1 Upvotes

Hey everyone,

I’m building a new AI-powered workflow automation platform designed to make creating, managing, and executing complex automations accessible to people without extensive technical knowledge. I’m looking for 3 to 5 people to test an early pilot version and give me honest, unfiltered feedback.

What you get in return:

Free lifetime access to the Pro/Self-hosted tier once we launch.

Direct input on the roadmap—if you need a specific integration or node right now, I’ll prioritize building it for you.

If you're interested, drop a comment below with one workflow you'd want to test on it, or shoot me a DM and I’ll send over the invite link!


r/sideprojects • • 2h ago

Feedback Request Badminton ELO - a German Badminton Rating Site

1 Upvotes

Hey,

I am a German badminton player. I think it is a shame that we, as a badminton community don't have something which tracks our real world performance (bax only works for states which track in turnier.de). So I created one. It's a side project powered by one single person (me 😅), because I want to know how good I am.

Now to the relevant parts:

• In the newest Release it has all games of every league (of every bundesland) in Germany, since 2010 this is 4.1 mil matches of around 200k players

• it pulls the latest matches on every tuesday, so it is always up to date (at least if everything works fine 😅).

• it has a prediction accuracy of 73% and a brier score of 0.174 (which I am actually proud of 😅). You can find an in depth description whit a comparison to similar systems here: https://www.badminton-elo.de/rating-algorithmus

Here is a screenshot of how my rating looks like:

https://imgur.com/a/NqaqBVn

You can find it here: www.badminton-elo.de

Check it out and let me know what needs to change, how you like it, which new features you'd like to see etc.

Also I'd like to connect to similar minding people which have a similar vision, be it national or internationally.


r/sideprojects • • 2h ago

Showcase: Prerelease Roast my vibe coded weekend build

Thumbnail
reddit.com
1 Upvotes

r/sideprojects • • 6h ago

Feedback Request A little is enough!

2 Upvotes

I built a fitness game for people who skip exercise because a small workout doesn’t feel worth doing

I’m a dad of two. A few squats and push-ups used to feel too insignificant to bother with. I’d tell myself I’d do a proper workout tomorrow, which made doing nothing today surprisingly easy.

So I built Above One, a web app where friends help each other stay active. I built it with Lovable and use it myself.

You join a group with friends, but everyone does their own activity, in their own time. Walking, running, cycling, or a few exercises at home all count.

The game is simple: each active day earns one point. You choose a two- or three-day window between activities. Logging an activity refills a gauge, which gradually runs down towards your deadline. If it reaches zero, your points reset. Friends can see when you’re getting close and give you a nudge.

The part that’s changed things for me is making small efforts feel worth recording and repeating. On a busy day, doing a few exercises keeps me involved instead of putting exercise off completely.

Something I’ve noticed in the small group using it so far: the people who keep coming back are busy parents. That’s an early observation, but it’s making me think more carefully about who I’m building this for.

Here it is: https://aboveone.app

I’d appreciate feedback on one thing in particular: when you open the landing page, is it clear why you’d use this with a friend? Explaining that simply has been harder than building a lot of the features.


r/sideprojects • • 3h ago

Discussion Never build a URL shortener. NEVER!

Post image
0 Upvotes

Nearly four years in: 180,000 short links, 10 million visits, 30,000 people who have shortened links, and 300,000 blocked attempts to reach malicious sites. Not a cent spent on SEO services or advertising. Sounds pretty good, except my total earnings are a whopping ~~$20~~  $19.56. Here’s how it started, what went wrong, and why I’m still happy to keep working on my URL shortener, Clipr.cc.

## How I got myself into this

I build online stores. One day, a client complained that their links didn’t work in a messaging app. After a lot of digging, I found the culprit: the desktop app was cutting them off. A URL shortener should fix that, right? Except the services I tried from Google’s top 20 results wouldn’t accept the domain in Punycode, the encoding used for non-Latin domain names. So I spent a couple of hours building the client a shortener. Problem solved.

A few years later, I needed to brush up on my coding skills for a new client project. I didn’t want to use their project as a training ground, so I decided to build something of my own. I remembered the shortener: a familiar problem, a small project, perfect for practice. What could possibly go wrong?

Here’s what I ended up with first version: https://web.archive.org/web/20240614164816/https://www.clipr.cc/

## Maybe it could cover the hosting bill

The shortener worked. It shortened links and redirected people. Punycode and all sorts of valid URL characters worked just fine. After a while in Google’s index, the first users and links started appearing.

I looked at the competition and ruled out building another Bitly. My budget for growing the project was $0. Hosting and the domain were my only expenses.

My plan was simple: free, minimal, no dashboards, a little advertising on the main pages. No popunders turning the site into Las Vegas after dark. No ads between clicking a short link and reaching the destination. And a modest Buy Me a Coffee link in the header.

I asked a few SEO specialists I knew for advice. The responses weren’t encouraging: too difficult, almost impossible for a shortener, these sites never last, and so on. I’m still waiting for that meeting with one of them. :)

So I handled the SEO myself, using what little I knew. Google seemed to like my changes: impressions would creep up a few percent, giving me a reason to keep going.

## 12 circles of ping-pong hell

Things were going well. New visitors, returning visitors, more traffic to the site and through the short links. Then Google sent me a social engineering warning. Scammers had started putting my service to work. I blocked the offending links, requested a review, and the warning was gone the next day. I didn’t notice much of an effect on my search rankings.

I’d had an abuse report form from the start. People did write in, and I checked the sites and blocked the malicious ones. So GOOGLE itself “asking” me to remove a bad link wasn’t much of a surprise. I physically can’t check every link created on the service.

Then things got properly ridiculous. Looking through the stats one day, I spotted a link with traffic shooting up. The destination looked like a familiar gaming platform, but the domain was one letter off. I checked it, confirmed it was phishing, blocked it without mercy, and went to bed. By morning, around 20,000 visits had hit my blocked-link page instead.

Scammers blocked. I win. The platform’s users are safe!!!

Yeah, right. A little later, I found my site glowing RED on VirusTotal: flags from roughly 30 phishing databases and a few lesser-known antivirus vendors!

That caught me completely off guard. I had to do something: antivirus software and corporate firewalls could now block my links for legitimate users. The site was only a year and a half old. I was tempted to switch domains or just abandon the whole thing. But I also wanted to see if I could get out of this mess.

I hunted down email addresses, tried broken contact forms, and went round in circles with phishing databases. Twelve circles of hell: one database pointed to another, the second to a third, the third to a fourth, and the fourth back to the first. I ended up forwarding their emails to each other. They were playing ping-pong, and I was the ball. It felt endless, but I eventually got the flags down to eight. Those last eight simply wouldn’t reply.

I felt beaten up. I’d blocked the link and stopped 90% of its traffic from reaching the scam, yet keeping my own service alive had cost me a ridiculous amount of time, energy, and nerves.

While dealing with the VirusTotal mess, I started studying phishing patterns and building a simple, practical system to help me quickly spot suspicious sites, sometimes entire networks of malicious links.

After years of this, I can often spot a phishing site at a glance. Sometimes I feel like I’ve become a neural network for detecting and blocking malicious links.

## Unblock my link or else…

One fine day, my system flagged a particularly suspicious link. The site offered a file to download and strongly insisted that you disable your antivirus first. I clicked Block with equal conviction.

I’d already forgotten about it when, five minutes later, an email arrived in very broken English: why had I blocked their “beautiful” link? I pointed them to the rules and was about to get on with my day when another email came in: “I don’t care. Unblock my link right now! You’ll have problems.”

Entertaining, but the link stayed blocked. The threats eventually turned into pleading and tears. Meanwhile, day after day, the blocked-visit counter kept climbing.

The next surprise came through Buy Me a Coffee. Apparently, in desperation, the scammer decided $20 might change my mind. I refunded the money. The link stayed blocked.

By the way, that’s the only time anyone has ever sent me anything through Buy Me a Coffee.

## So what did I actually get out of it?

First, thanks for making it this far.

This kind of shortener barely earns anything, and monetizing it is harder than it looks. Maybe one day it’ll cover the hosting bill. When? Good question.

But I love this project. It’s an experiment that’s still running. Where else would I get to learn all of this?

  • Testing usability. Seeing people actually use a feature you thought up before falling asleep is a lovely feeling.

  • Optimizing a service to handle peaks of 200,000 visits a day on modest, though reliable, shared hosting.

  • Dealing with half a million bot requests a week and DDoS attacks.

  • Spotting phishing quickly and building tools to analyze suspicious sites.

  • Collecting analytics under load, without microservices.

  • Doing SEO beyond just the development side.

  • Even writing articles nobody reads. :) I put my own cybersecurity articles on the blocked-link pages, hoping for 10 readers per 1,000 visits. I got about five per 10,000.

  • A/B testing, and plenty more.

  • $19.56 from ads 

Someone once offered to buy the service. But when I imagined what I’d do without all these experiments, I turned them down without even asking the price. :)

For me, the shortener has been about experience as a developer and beyond. Sometimes I even feel like a little internet Superman: 300,000 attempts to reach malicious sites stopped along the way.

Happy to answer questions when I can. For now, I’m off to build another feature and block some more malicious links.


r/sideprojects • • 3h ago

Showcase: Free(mium) I drive Lyft by day and spent this year building a full audio studio that runs in the browser

1 Upvotes

I’m not a coder. I had the idea, a good set of ears, and a lot of late nights building it with AI (Claude).

The problem: beginners who want to fix a podcast, make a slowed + reverb version of a song, or make a beat have two bad choices. Pro software that is overwhelming and expensive, or sketchy free sites that do one thing and plaster ads everywhere.

What it is: AudioDoc, a free audio studio that runs in the browser. One-click fixes for voice and podcasts, Slowed + Reverb, a Beat Lab with drums and real instruments, multitrack editing, recording, and a filter sweep that makes your intro sound like an old radio before the beat drops.

How it’s built:

  • One single HTML file, no frameworks. Everything runs on the Web Audio API.

  • Audio is processed right on your computer, nothing gets uploaded.

  • Instruments use free soundfont recordings (FluidR3).

  • 228 automated tests that play the app like a robot before every release.

What I learned: AI can write code fast, but it can’t hear. Almost every real bug was found by me listening and saying “that doesn’t sound right”: a track drifting 16 seconds out of sync, a flute landing a hair behind the piano, a limiter that did nothing you could hear. We’re over 1,200 builds in.

I’d love honest feedback, good or bad: audiodoc.io