Join the Hacktoberfest Open-Source AI Challenge: Side Hustle! $2,550 in Prizes Across 18 Winners.

Week 2 of our five Hacktoberfest DEV Challenges starts today! Running through October 18, the Hacktoberfest Open-Source AI Challenge: Week 2 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 1: Touch Grass? 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 17 partner categories. See all five challenges and current partner categories on the HF26 DEV Challenge Hub.

Build something with open-weight models or open-source AI that someone would actually pay for.

That can mean running an open-weight model, building on an open-source agent harness or framework, running inference locally, or all three. Whatever you pick, the open pieces should be what makes your project work.

Think small, specific, and useful. The best builds here solve a real problem for a real person, whether that's a freelancer, a small business owner, a niche hobby community, or your friend who keeps complaining about the same tedious task. A few ideas to get you going:

In your post, tell us why open innovation matters for what you built. Does running your own model keep costs low enough that the business actually works? Keep your customers' data private? Let you fine-tune for a niche that a general-purpose API handles poorly? Avoid getting locked into someone else's pricing? Tell us where your open-based approach worked better than a closed one.

Bonus points if you land your first user. Get it in front of someone, let them use it, and tell us how it went. Did they pay? Would they? What did they ask for next?

Alongside our overall winner, we have 17 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.

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, including Tinker, Render, and Backboard. Claim yours at hacktoberfest.com/my.

A huge thank you to our partners for making these prizes possible!

This is DEV, so your write-up matters most.

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.

All participants with a valid submission will receive a completion badge.

Publish a post on DEV using the submission template below. Tell us what you built and who would pay for it, show us a demo, and explain why open innovation matters for what you built. If you landed your first user, tell us about it!

Please review our judging criteria, rules, guidelines, and FAQ page before submitting so you understand our participation guidelines and official contest rules, such as eligibility requirements.

Week 3 launches Monday, October 19 with a brand-new theme. Be sure to register so you don't miss the announcement.

Register now to be notified as details drop.

Questions about the challenge? Drop them in the comments below.