Abalone
data tracking and analytics for conservation efforts
ActiveWorkflow.org
turn complex requirements to workflows
AgileVentures
source code to agileventures.org
Airesis
eDemocracy
Alaveteli
easy FOIA requests for any jurisdiction
Amahi
your personal cloud and media server
AppPerf
application and performance monitoring tool
Autolab
course management and auto-grading of assignments
BareMetrics.com
v1 of baremtrics.com
Bike Index
the internet's bike registry
brief-ideas
journal for brief ideas
Brimir
an email helpdesk
Calls For Proposal App
manage a conference CFP
Case File Editor
editor for digital case files
Catarse
open-source crowdfunding platform
CircuitVerse.org
circuit simulator
Clain for Crown Court Defense
advocacy for defense payments
CodeCuriosity.org
platform to reward OSS contributors
CodeTriage
directory of open-source projects with open issues
Concerto
digital signage system
consul
open government and participation software
Coursemology
open-source gameified learning platform
Cuttlefish
a good-enough SMTP server so you can ditch SMTP providers
Diaspora
community-run, distributed social-network
Do Continuous Integration Yourself
open-source CI server
Droptune
music notifications for Spotify and Apple Music
Drug Gene Interaction Database
The Genome Institute's drug gene interaction database
Duckrails
tool to mock API endpoints
EasyRaceLapTimer
open-source IR lap time tracker
ebwiki.org
database of police abuse cases against people of color
Ecosystem Dashboard
open-source ecosystem monitoring
Ekylibre
farm management information system
Email Dashboard
email suite for marketing and CRM
Envizon
network visualization and pentest reporting
Errbit
open source, self-hosted error catcher
Expertiza
peer-reviews app, supported by the National Science Foundation
Fairmondo
free market place in the hand of the users
Fat Free CRM
a clean, customizable CRM
FederalRegister.gov
daily journal for the United States Government
Feedbin
open-source feed reader for multiple platforms
FeedBunch
simple and elegant reader
fromthepage.com
crowdsource handwritten documents
Gamocosm.com
Minecraft server hosting
Growstuff
tool for small-scale food growers
Gwaphics
graphic design tool
Hackathon Manager
hackathon registration and logistics
HellRaiser
vulnerability scanner
Helpful
simple and elegant support system
Helpy
A Modern Helpdesk Alternative
Hound
Your code, always in style.
Hours
Time registration that doesn't suck.
HRMS
HR management
Huboard.com
better GitHub issues
huginn
open-source IFTTT
if-me.org
mental health communication
Intercity
web-based Dokku deployment
Juvia
commenting server of the likes of Discus or IntenseDebate
Lale Help
collaborative platform for refugee support
LearnAwesome.org
social network of learners
Lewsnetter
email marketing application
libraries.io
open-source discovery service
lobsters
link-aggregation site, inspired by Hacker News
LumenDatabase
database of legal complaints and requests for removals
Morph.io
web scraping tool
Octobox
GitHub notification manager
OneBody
church management software
Open Build Service
build service for Linux packages
OpenFarm
open database for farming and gardening knowledge
OpenFoodNetwork
software to manage the lifecycle of food
openSNP
annotate your SNP-set
Open Source Billing
Beautifully Simple Billing Software
Open-Source Event Manager
event management tool tailored to conferences
Open Split Time
endurance event data management
openstreetmap.org
crowd-sourced map of the world
Panoptes
API to support user-defined research projects
pinballmap.com
source code to pinballmap.com
Plylst
Spotify playlist tool
Pokr
agile estimating and planning
Postal
mail delivery platform for incoming and outgoing e-mail
PublicLab.org
collaborative knowledge-exchange platform
Punchclock
simple electronic punch clock
Racing On Rails
bike racing association management
Registry
TLD management software
Reservations
equipment loans and reservations software
rubygems.org
The Ruby community's gem hosting service
Sanataro
household accounting software
sharetribe
Marketplace platform
SmartVPN Billing
billing management for hosting
Squash
exception reporting and bug analysis by Square
Staytus
status pages
StockAid
manages inventory for the Grateful Garment Project
TagTeam
social tagging for academics
TaxonWorks
workbench for biodiversity informatics
TimeOverflow
time banking system
tip4commit.com
reward contributors
Tracks
software for implementing David Allen's Getting Things Done™ methodology
Trado
simple e-commerce platform for developers
uk-postcodes
postcodes application
Upcase.com
learning platform for programming