Hacktoberfest 2026 DEV Challenges: Five Challenges, One Prompt, a New Theme Every Week
Hacktoberfest is here, and this October we’re running five DEV Challenges back to back. Every challenge uses the same prompt. Every challenge gets its own theme, and each theme stays secret until the day it launches. This year’s Hacktoberfest is not about open source pull requests. There’s no PR count to hit and no repos to hunt for. Instead, you build a brand-new project with open-source AI at its core, and write about it on DEV. Here’s everything you need to know about Hacktoberfest 2026. First up is our Hacktoberfest Weekend Challenge, launching in just a few hours. Then a new challenge launches every Monday in October. How It Works Five challenges: a weekend challenge to start, then a new one every Monday in October. One prompt: the same prompt for all five, so you always know what we’re looking for. A new theme each time: the theme gives each challenge its own flavor. We reveal it the day the challenge launches. One submission per challenge: that’s up to five in October. Each submission is automatically in the running for the overall prize and every partner category it qualifies for. You can win once per challenge. New projects, not pull requests: each submission is a new project built during that challenge’s window. Pull requests to existing projects don’t count this year. Joining late? No problem. Every challenge is a fresh start, so someone who finds us in week four competes on the same footing as someone who’s been here since day one. Our Prompt Build something with open-source AI at its core. 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. In your post, tell us why open innovation matters for what you built. Does it run on a laptop with no internet? Keep someone’s data off a server they don’t control? Let you fine-tune, swap models, or change how your agent behaves? Cost nothing to run? Tell us where your open-based approach worked better than a closed one. Prizes Every challenge has its own winners, and we’ll share each challenge’s prizes when it launches. Here’s what’s up for grabs in the Weekend Challenge. Overall winner (1): $250, a DEV++ membership, and an exclusive DEV badge. Featured categories (6): $200 for each winner. Best Use of Render: Use Render as your project’s AI runtime, to host an agent’s front end, or to run Hermes or OpenClaw. Best Use of TabPFN: Use TabPFN, Prior Labs’ tabular foundation model, to forecast, predict, classify, or spot anomalies from historical data like a CSV. Use it inside an agent tool (with or without the MCP server) or on its own. Best Use of Tinker: Use Thinking Machines’ Tinker to fine-tune a model for a specific task, and show a clear improvement in performance, latency, or cost over a baseline. Best Use of Arduino: Build with an Arduino UNO Q: run a model on the board, build a physical agent that senses and acts, or optimize a model for it with Qualcomm AI Hub. Open to anyone building with an UNO Q, whether you got one at an in-person Fest or have your own. Best Use of DigitalOcean: Build or deploy your project on DigitalOcean: host your app or agent, run an open-weight model on a GPU Droplet (1-Click Models make this quick), or build an agent on the Gradient AI Platform. Best Use of Gemma: Use Gemma, Google’s open-weight model, in building your project: run it locally, fine-tune it, or serve it through Google Cloud or another provider. Partner categories (10): $100 for each winner. Best Use of Backboard: Build with R-CLI, Backboard’s open-source terminal coding agent, compare open-weight models through a single Backboard API key, or give an open-source project’s assistant memory and RAG. Best Use of ElevenLabs: Give an open-source agent a voice, transcribe audio for a local model, or generate narration for your demo. Best Use of Entire: Share the agent sessions behind your project in the write-up, or search past agent work to explain why code exists. Best Use of GitHub Copilot: Build with Copilot’s coding agent, the Copilot CLI, or the new Copilot app, automate your project with GitHub Actions, or review contributors’ PRs with Copilot. Best Use of Mastra: Orchestrate an agent over open models, add memory and tools to a chat agent, or build a workflow that triages GitHub issues. Best Use of MongoDB Atlas: Use Atlas as your data layer: Atlas Vector Search for retrieval, long-term memory for an agent, or the database behind an app built on an open-weight model. Best Use of Sentry Agent Tracing: Show your agent’s work: how it’s set up, how it performs (latency, tokens, cost), what you found, and how you debugged it. Include traces or screenshots in your write-up. Best Use of SerpApi: Give an agent live web search, ground a RAG app in fresh results, or track news for an open-source project. Best Use of Temporal: Make your agent durable. Wrap it in a Temporal workflow so it survives failures, retries flaky tool calls, and picks up where it left off. Best Use of Tiger Data: Store embeddings with pgvector, run hybrid keyword and vector search for an agent, or let an agent manage a database through Tiger MCP. Partner categories may change from challenge to challenge as new partners join. Every winner also gets an exclusive DEV badge, and everyone with a valid submission gets a completion badge. You don’t need to use any partner technology to win the overall prize, but if you’ve been curious about any of this tech, here’s your excuse to try it. 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 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, Backboard, and ElevenLabs. 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. A great project with a thin write-up won’t win. Tell us the story. 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 at the core of the project? Does it fit this challenge’s theme? 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. The Schedule Challenge Theme Launches Winners Announced Weekend Challenge Revealed at launch Thu Oct 1 (PT/ET), Fri Oct 2 (elsewhere) Week of Oct 5 Week 1 Revealed at launch Mon Oct 5 Week of Oct 12 Week 2 Revealed at launch Mon Oct 12 Week of Oct 19 Week 3 Revealed at launch Mon Oct 19 Week of Oct 26 Week 4 Revealed at launch Mon Oct 26 Week of Nov 2 Each challenge’s page has its exact deadline in every timezone. Follow the #hf26challenge tag so you don’t miss a reveal. 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. Drop questions in the comments below, too. Happy Hacktoberfest!