Week 3 of our five Hacktoberfest DEV Challenges starts today! Running through October 25, the Hacktoberfest Open-Source AI Challenge: Week 3 gives you a full week to build.
This year's Hacktoberfest is all about building brand-new projects with open-source AI and open-weight models. Here's everything you need to know about Hacktoberfest 2026.
Missed Week 2: Side Hustle? No problem. Every challenge is a fresh start, so you're competing on the same footing as everyone else.
This week, we'll select one overall winner and a winner in each of our 20 partner categories. See all five challenges and current partner categories on the HF26 DEV Challenge Hub.
Let's get to it (slowly)! 🦥
Prize Categories
Alongside our overall winner, we have 20 prize categories for projects that use a specific partner's technology. You don't need to use any of these to win the overall prize, but if you've been curious about any of this tech, this is a great excuse to give one a try. Full descriptions are on the hub.
Featured categories:
- Best Use of Render
- Best Use of TabPFN
- Best Use of Tinker
- Best Use of Arduino
- Best Use of DigitalOcean
- Best Use of Gemma
Partner categories:
- Best Use of Auth0 for AI Agents 🆕
- Best Use of Backboard
- Best Use of Browserbase 🆕
- Best Use of ElevenLabs
- Best Use of Entire
- Best Use of GitHub Copilot
- Best Use of Mastra
- Best Use of MongoDB Atlas
- Best Use of Sentry Agent Tracing
- Best Use of SerpApi
- Best Use of Temporal
- Best Use of Tiger Data
- Best Use of Ultramarine (Paper Instruments) 🆕
- Best Use of a .tech Domain
Pro Tip: Partner category winners come from a smaller pool of submissions, so your odds are meaningfully higher.
Note: One project can enter every category it genuinely uses, but you can only win once per challenge, and we'll aim to celebrate as many different builders as possible across the month.
Free credits: several partners are giving participants credits and promo codes. Claim yours at hacktoberfest.com/my.
A huge thank you to our partners for making these prizes possible!
Judging Criteria
This is DEV, so your write-up matters most.
- Writing Quality (weighted most heavily): Is the post clear and engaging? Does it explain what you built, who it's for, and why open innovation matters?
- Relevance to the Prompt and Theme: Is open-source AI or open-weight models at the core of the project? Does it genuinely save effort, help someone relax, or make life easier?
- Creativity: Is it an original idea, or a fresh take on a familiar problem?
- Technical Execution: Does it work, and is it well built?
- Use of Partner Technology (optional): If you're entering a partner category, does the project use that technology in a meaningful way?
Show your work. We'd love to see how you built it. Save your agent session with DevRelay and embed it in your post, or link to it. It's optional, but it helps the judges understand your process.
Prizes
- Overall winner (1): $250 USD, a DEV++ membership, and an exclusive DEV badge
- Featured category winners (6): $200 USD and an exclusive DEV badge each
- Partner category winners (14): $100 USD and an exclusive DEV badge each
All participants with a valid submission will receive a completion badge.
Need Help?
- New to Hacktoberfest this year? Start with Everything You Need To Know About Hacktoberfest 2026.
- Come hang out and ask questions in the MLH Discord.
- The challenge page has resources from our partners to help you get started.
Important Dates
- October 19: Hacktoberfest Open-Source AI Challenge: Week 3 begins!
- October 20: International Sloth Day 🦥
- October 25: Submissions due at 11:59 PM PDT
- Week of October 26: Winners announced
Looking Ahead
Week 4, our final Hacktoberfest challenge, launches Monday, October 26 with a brand-new theme. Be sure to register so you don't miss the announcement.
Hacktoberfest Open-Source AI Challenge: Week 4
October 26, 2026Register now to be notified as details drop.
Questions about the challenge? Drop them in the comments below.
Take it slow, happy Hacktoberfest, and good luck!
Top comments (40)
May the slow and steady win the race this time as well, like all the other times 🤣🥰
Best wishes to all those who'll participate 🤞
And just in case you need some more free credits: 👇
Grab $250 in Free Cloud VM Credits from Docker (Before Oct 31, 2026)!
Good luck!!!🥰
BTW, this challenge suits your DEV user name perfectly! May be you should join ... just saying. 🤣🥰
Maybe DEV got inspired by my Dev user name and came up with this challenge, lol! Just kidding 🤣By the way, DEV should launch a Halloween challenge too! 🎃👻
Thanks! 🥰
Just published my submission for Week 3: SlothLog (🦥)!
It’s an offline, privacy-first developer utility that inspects local git commits, clusters them into work sessions by ticket ID, and writes clean timesheet worklogs using local Gemma 2 2B (with Sentry tracing and a Render cloud demo). No more wasting 45 minutes every Friday afternoon trying to remember what you did on Tuesday!
Check it out here: SlothLog
Happy International Sloth Day and good luck everyone! 🦥✨
Hi Alessio! I read your write-up—the ticket grouping and editable hour controls are useful touches. I'm working on a nearby problem with SlothPulse: local Gemma drafts a standup from commits and an optional traceback, with Python binding each item to its source.
One failure surprised me: a summary cited the correct commit but turned ‘submission handoff’ into ‘submitted.’ Source validation passed, yet the meaning still needed correction. Have you seen Gemma 2 2B turn tentative work into a completed accomplishment, especially with short ‘wip’ commits? Curious how you handle that before copying a worklog.
I preserved the raw example here if useful: github.com/TengByte/slothpulse/tre...
Good luck with the challenge! 🦥
Hi @tengbyte! Thanks so much for reading and for the thoughtful question! SlothPulse sounds like a fantastic concept—binding standup bullets to source commits and tracebacks is super smart.
You hit on a very real challenge: compact models like Gemma 2 2B definitely suffer from an inherent "completion bias". Because summarization fine-tuning heavily associates commit logs with deliverables, the model loves to turn tentative phrasing like "wip: auth handoff" into triumphant assertions like "Completed auth implementation."
Here’s how we approach and mitigate this in SlothLog:
0.2to minimize creative extrapolation and keep Gemma tightly tethered to the actual commit verbs.wip refactoring,investigating edge case,drafting tests), the chronological timeline helps anchor the reality of the work better than a single ambiguous commit. In our deterministic fallback, we also explicitly filter out bare keywords likewip,test, orcommitso low-signal commits don't get inflated.I took a peek at your evidence repo—the ground-truth binding you’re doing with Python AST / source references is really neat and adds that layer of determinism small LLMs often lack.
Best of luck with SlothPulse and Hacktoberfest Week 3! 🦥🚀
Thanks, Alessio! The session-grouping approach gives me a useful experiment to try on ambiguous commits. Small clarification: SlothPulse uses Python to validate source references and coverage, rather than AST analysis. As our example showed, a valid reference can still accompany an incorrect completion claim—so I agree that human review matters. Thanks for sharing your approach, and good luck! 🦥
Thanks for the clarification, Teng! That makes total sense—ground-truth referencing confirms where the code changed, but discerning semantic intent and completion state is exactly where human review still shines.
Really glad the session-clustering angle gives you an interesting experiment to explore. Looking forward to seeing where you take SlothPulse!
Have a great Hacktoberfest, and happy hacking! 🦥✨
Well, I'm not gonna be left out even though this is my first submission and I had to rush things just to meet up.
dev.to/thesonofraj/geosim-lab-a-vi...
My Week 3 entry is
PDFme
a local, offline PDF toolkit for large print files. It compresses, splits, merges and removes image backgrounds on your own computer. Background removal uses an open-source model, and Gemma through Ollama handles page labels.
The most useful finding wasn’t a speed number. It was a skip. A photo covering 91% of a page was ignored by my 90% rule, and the tool only said “1 not processed”. It didn’t say why, so I changed the message to name the reason and the option that fixes it.
Write-up, code and demo: dev.to/parnita_singh_73778510977/p...
I’d welcome feedback from anyone who has removed a background from a photo that fills the whole page. 🐘
I almost didn't make it due to time crunch
but its done now dev.to/0shuvo0/im-too-lazy-to-writ...
I recently built Spotlight — a launcher for people who hate waiting!
It's designed to make accessing apps and tools faster and simplify everyday workflows. I'd love to explore how open-source AI and local models could make it even smarter and more privacy-friendly.
🔗 Check out my project: dev.to/chndrapratapsingh/spotlight...
I'd appreciate your feedback! 🦥💻
This is my 3rd hackathon and again submitted at the last minute: 🫣dev.to/mohammad515253/sloth-migrat...
Loved this week's theme. Sloth energy is exactly what I was going for 🦥
I built Actum, an Android app where you say one messy sentence ("buy rice, wake me at 6 tomorrow, mark 4th Nov as my birthday") and Gemma 4, running on the phone, turns it into ready cards for your to-do list, alarm and calendar. One tap each and it's done. The app doesn't even have the internet permission, so nothing you share into it can leave your phone.
The part I'm proudest of: I wrote 100 fresh test sentences, froze them, and measured rules vs Gemma vs the hybrid on a real phone. I published the failures too (prompt injection and negations still slip through).
Write-up: dev.to/aritra_maity_e3bce29864e8/a...
Code: github.com/AM2004legend/ActIum
Would genuinely love feedback, especially from anyone running models on-device. Good luck everyone!
Looking forward to seeing all the submissions.
Excited for the upcoming events!!!
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