Challenge Project

Enter your availability to find a time that works for everyone!

📂 Demo

We are using to plan our DINAcon HACKnight meetups this year. It takes an interesting approach to collect personal preference in a data-protection-conformant way, and presents an original interface to enter and visualize group preferences. Despite being a small project, we found it reliable and useful for planning the HACKnight.

Donate: PayPal

{ hacknight challenges }

What tools do you use for planning meetings for your open initiative? Learn about some of the open source alternatives. Set up a plan for your next code jam, footy match, or Jass night at

Consider setting up your own instance on a free Google Cloud trial. Let the developers know how straightforward the process is, if anything is lacking in the documentation. Become a translator or make a donation.

See the instructions below to deploy and contribute to the open source project. Check out for example issue #143 that we are already discussing with devs.

Crab Fit avatar

Align your schedules to find the perfect time that works for everyone. Licensed under the GNU GPLv3.

Crab Fit - Use your availability to find a time that works for everyone | Product Hunt


⭐️ Bugs or feature requests

If you find any bugs or have a feature request, please create an issue by clicking here.

🌐 Translations

If you speak a language other than English and you want to help translate Crab Fit, fill out this form:


  1. Clone the repo.
  2. Run yarn in both backend and frontend folders.
  3. Run yarn dev in the backend folder to start the API. Note: you will need a google cloud app set up with datastore enabled and set your GOOGLE_APPLICATION_CREDENTIALS environment variable to your service key path.
  4. Run yarn dev in the frontend folder to start the frontend.

🔌 Browser extension

The browser extension in crabfit-browser-extension can be tested by first running the frontend, and changing the iframe url in the extension's popup.html to match the local Crab Fit. Then it can be loaded as an unpacked extension in Chrome to test.


Deployments are managed with GitHub Workflows.

To deploy cron jobs (i.e. monthly cleanup of old events), run gcloud app deploy cron.yaml.

🔌 Browser extension

Compress everything inside the crabfit-browser-extension folder and use that zip to deploy using Chrome web store and Mozilla Add-on store.

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Event finished

Did anyone else notice we put 23.11.23 on the community calendar? #failftw .. If we rock these #HACKnights then let's make it a tradition 😄

23.11.2022 22:05 ~ loleg

Event started

Got invited to the Transifex platform, most of the languages have translations already, but Italian doesn't - it'd be awesome if we could contribute to that one.

17.11.2022 08:41 ~ loleg

We have found some overlaps in our schedules and are setting up calls for the HACKnights. Feel free to add your own on this page.

14.11.2022 08:59 ~ loleg

Edited (version 5)

14.11.2022 08:57 ~ loleg

Repository updated

14.11.2022 08:56 ~ loleg

First post View challenge

14.11.2022 08:56 ~ loleg


All attendees, sponsors, partners, volunteers and staff at our hackathon are required to agree with the Hack Code of Conduct. Organisers will enforce this code throughout the event. We expect cooperation from all participants to ensure a safe environment for everybody.

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