free-for-dev

Developers and Open Source authors now have a massive amount of services offering free tiers, but it can be hard to find them all in order to make informed decisions.

This is list of software (SaaS, PaaS, IaaS, etc.) and other offerings that have free tiers for developers.

The scope of this particular list is limited to things infrastructure developers (System Administrator, DevOps Practitioners, etc.) are likely to find useful. We love all the free services out there, but it would be good to keep it on topic. It's a bit of a grey line at times so this is a bit opinionated; do not be offended if I do not accept your contribution.

You can help by sending Pull Requests to add more services. Once I have a good set of links in this README file, I'll look into a better layout for the information and links (help with that is appreciated too).

NOTE: This list is only for as-a-Service offerings, not for self hosted software.

Table of Contents

• Source Code Repos
• Tools for Teams and Collaboration
• Code Quality
• Code Search and Browsing
• CI / CD
• Automated Browser Testing
• Security and PKI
• Management Systems
• Log Management
• Translation Management
• Monitoring
• Crash and Exception Handling
• Search
• Email
• CDN and Protection
• PaaS
• BaaS
• Web Hosting
• DNS
• IaaS
• DBaaS
• STUN, WebRTC, Web Socket Servers and Other Routers
• Issue Tracking and Project Management
• Storage and Media Processing
• Design and UI
• Data Visualization on Maps
• Package Build System
• IDE and Code Editing
• Analytics, Events and Statistics
• International Mobile Number Verification API and SDK
• Payment / Billing Integration
• Docker Related
• Vagrant Related
• Miscellaneous
• APIs, Data, and ML
• Other Free Resources

Source Code Repos

• bitbucket.org — Free unlimited public and private repos (Git and Mercurial) for up to 5 users
• chiselapp.com — Unlimited public and private Fossil repositories
• github.com — Free for an unlimited number of public repositories
• about.gitlab.com — Unlimited public and private Git repos with unlimited collaborators
• hub.jazz.net — Unlimited public repos, private repos free for up to 3 accounts
• visualstudio.com — Free unlimited private repos (Git and TFS) for up to 5 users per team
• fogcreek.com — Free unlimited public and private repos (hybrid of Git and Mercurial) for 2 users
• plasticscm.com — Free for individuals, OSS and nonprofits organizations
• assembla.com — Free private Subversion, Git, and Perforce repositories
• cloud.google.com — Free private Git repositories hosted on Google Cloud Platform. Supports syncing with existing GitHub and Bitbucket repos. Free Beta for up to 500 MB of storage

Tools for Teams and Collaboration

• appear.in — One click video conversations, for free
• flowdock.com — Chat and inbox, free for teams up to 5
• slack.com — Free for unlimited users with some feature limitations
• hipchat.com — Free for unlimited users with some feature limitations
• gitter.im — Chat, for GitHub. Unlimited public & private rooms, free for teams of up to 25
• hangouts.google.com — One place for all your Conversations, for free, need a Google account
• seafile.com — Private or cloud storage, file sharing, sync, discussions. Private version is full. Cloud version has just 1 GB
• sameroom.io — Free for unlimited users with some feature limitations
• yammer.com — Private social network standalone or for MS Office 365. Free, just a bit less admin tools and users management features
• helpmonks.com — Shared inbox for teams, free for Open Source and nonprofit organizations
• typetalk.in — Share and discuss ideas with your team through instant messaging on the web or on your mobile
• talky.io — Free group video chat. Anonymous. Peer‑to‑peer. No plugins, signup, or payment required
• sourcetalk.net — Code discussion tool, free for open code talks
• helplightning.com — Help over video with augmented reality. Free without analytics, encryption, support
• evernote.com — Tool for organizing information. Share your notes and work together with others
• wunderlist.com — Share your lists and work collaboratively on projects with your colleagues, free on iPhone, iPad, Mac, Android, Windows and the web
• doodle.com — The scheduling tool you'll actually use. Find a date for a meeting two times faster
• sendtoinc.com — Share links, notes, files and have discussions. Free for 3 and 100 MB
• zoom.us — Secure Video and Web conferencing, add-ons available. Free limited to 40 minutes
• ideascale.com — Allow clients to submit ideas and vote, free for 25 members in 1 community
• filehero.io — Make it easy to access your company's file storage from a corporate download page. Free for 5 concurrent downloads
• wistia.com — Video hosting with viewer analytics, HD video delivery, and marketing tools to help understand your visitors, 25 videos and Wistia branded player
• cnverg.com — Real-time shared visual workspace, whiteboard, GitHub integration. Free 5 GB, 5 spaces and 5 collaborators, no GitHub repos

Code Quality

• tachikoma.io — Dependency Update for Ruby, Node.js, Perl projects, free for Open Source
• gemnasium.com — Dependency Update for Ruby, Node.js projects, free for Open Source
• deppbot.com — Automated Dependency Updates for Ruby projects, free for Open Source
• landscape.io — Code Quality for Python projects, free for Open Source
• codeclimate.com — Automated code review, free for Open Source
• houndci.com — Comments on GitHub commits about code quality, free for Open Source
• coveralls.io — Display test coverage reports, free for Open Source
• scrutinizer-ci.com — Continuous inspection platform, free for Open Source
• codecov.io — Code coverage tool (SaaS), free for Open Source
• insight.sensiolabs.com — Code Quality for PHP/Symfony projects, free for Open Source
• codacy.com — Automated code reviews for PHP, Python, Ruby, Java, JavaScript, Scala, CSS and CoffeeScript, free for Open Source
• pullreview.com — Automated Code Review for Ruby in GitHub, Bitbucket and GitLab, free for Open Source
• gocover.io — Code coverage for any Go package
• goreportcard.com/ — Code Quality for Go projects, free for Open Source
• inch-ci.org — Documentation badges for Ruby, JS and Elixir
• scan.coverity.com — Static code analysis for Java, C/C++, C# and JavaScript, free for Open Source
• webceo.com — SEO tools but with also code verifications and different type of advices
• zoompf.com — Fix the performance of your web sites, detailed analysis
• websitetest.com — Yotta's tool to optimize web sites, free limited version online
• gtmetrix.com — Reports and thorough recommendations to optimize websites
• browserling.com — Live interactive cross-browser testing, free only 3 min. sessions with MS IE 9 under Vista at 1024 x 768 resolution
• loadfocus.com — Load and speed tests for websites, mobile apps and APIs, monitoring,... Free 5 tests/month, 120 clients/test, 1 monitor, 1 location,...
• versioneye.com — Monitor your source code and notify about outdated dependencies. Free for Open Source and public repos
• beanstalkapp.com — A complete workflow to write, review & deploy code), free account for 1 user and 1 repository, with 100 MB of storage
• testanywhere.co — Automatic test website or web app continuously and catch bugs in the early stages, free 1,000 tests/month

Code Search and Browsing

• sourcegraph.com — Java, Go, Python, Node.js, etc., code search/cross-references, free for Open Source
• searchcode.com — Comprehensive text-based code search, free for Open Source

CI / CD

• codeship.com — 100 private builds/month, 5 private projects, unlimited for Open Source
• circleci.com — Free for one concurrent build
• travis-ci.org — Free for public GitHub repositories
• wercker.com — Free for public and private repositories
• drone.io — CI platform that includes browser testing, free for Open Source
• semaphoreci.com — 100 private builds/month, unlimited for Open Source
• shippable.com — Free for 1 build container, private and public repos, unlimited builds
• snap-ci.com — Free for public repositories, 1 build at the time
• appveyor.com — CD service for Windows, free for Open Source
• github.com — Comparison of Continuous Integration services
• ftploy.com — 1 project with unlimited deployments
• deployhq.com — 1 project with 10 daily deployments
• hub.jazz.net — 60 minutes of free build time/month
• styleci.io — Public GitHub repositories only
• deploybot.com — Free for 1 repository, private or public. Supports any service you can throw at it
• bitrise.io — iOS CI/CD with 200 free builds/month
• saucelabs.com — CI with scalable testing for mobile and web apps, free for Open Source

Automated Browser Testing

• gridlastic.com — Selenium Grid testing with free plan up to 4 simultaneous selenium nodes/10 grid starts/4,000 test minutes per month
• browserstack.com — Manual and automated browser testing, free for Open Source
• EveryStep-Automation.com — Records and replays all steps made in a web browser and creates scripts,... free with fewer options

Security and PKI

• crypteron.com — Cloud-first, developer-friendly security platform prevents data breaches in .NET and Java applications
• vaddy.net — Continuous web security testing with continuous integration (CI) tools. 3 domains, 10 scans history for free
• letsencrypt.org — Free SSL Certificate Authority with certs trusted by all major browsers
• globalsign.com — Free SSL certificates for Open Source
• startssl.com — Free SSL certs
• wosign.com — Free SSL certs. Up to 5 domain names for 2 years period. China authority
• soclall.com — Free up to 1,000 users login, post, share through top 20+ social networks
• stormpath.com — Free user management, authentication, social login, and SSO
• auth0.com — Hosted free for development SSO
• getclef.com — New take on auth unlimited free tier for anyone not using premium features
• ringcaptcha.com — Tools to use phone number as id, available for free
• ssllabs.com — Very deep analysis of the configuration of any SSL web server
• qualys.com — Find web app vulnerabilities, audit for OWASP Risks
• alienvault.com — Uncovers compromised systems in your network
• duo.com — Two-factor authentication (2FA) for website or app. Free 10 users, all authentication methods, unlimited, integrations, hardware tokens
• tinfoilsecurity.com — Automated vulnerability scanning. Free plan allows weekly XSS scans
• acunetix.com — Free vulnerability and network scanning for 3 targets
• ponycheckup.com — An automated security checkup tool for Django websites
• foxpass.com — Hosted LDAP and RADIUS. Easy per-user logins to servers, VPNs, and wireless networks. Free for 10 users
• opswatgears.com — Security Monitoring of computers, devices, applications, configurations,... Free 25 users and 30 days history
• bitninja.io — Botnet protection through a blacklist, free plan only reports limited information on each attack
• onelogin.com — Identity as a Service (IDaaS), Single Sign-On Identity Provider, Cloud SSO IdP, 3 company apps and 5 personal apps, unlimited users
• logintc.com — Two-factor authentication (2FA) by push notifications, free for 10 users, VPN, Websites and SSH
• report-uri.io — CSP and HPKP violation reporting

Management System

• bitnami.com — Deploy prepared apps on IaaS. Management of 1 AWS micro instance free
• visualops.io — 3,600 instance hours/month free

Log Management

• papertrailapp.com — 48 hours search, 7 days archive, 100 MB/month
• logentries.com — Free up to 5 GB/month with 7 days retention
• loggly.com — Free for a single user, see the lite option
• sematext.com — Free up to 500 MB/day, 7 days retention
• sumologic.com — Free up to 500 MB/day, 7 days retention

Translation Management

• lingohub.com — Free up to 3 users, always free for Open Source
• getlocalization.com — Free for public projects
• webtranslateit.com — Free up to 500 strings
• transifex.com — Free for Open Source
• oneskyapp.com — Limited free edition for up to 5 users, free for Open Source
• crowdin.com — Unlimited projects, unlimited strings and collaborators for Open Source

Monitoring

• opbeat.com — ​Instant performance insights for JS developers. Free with 24 hours data retention
• checkmy.ws — Free 15 days full demo and 3 websites, forever free for Open Source
• appneta.com — Free with 1 hour data retention
• thousandeyes.com — Network and user experience monitoring. 3 locations, plus 20 data feeds of major web services free
• datadoghq.com — Free for up to 5 nodes
• stackdriver.com — Free monitoring up to 10 servers/hosted services
• keymetrics.io — Free for 2 servers with 7 days data retention
• newrelic.com — Free with 24 hours data retention
• nodequery.com — Free basic server monitor up to 10 servers
• watchsumo.com — Free website monitoring, 50 Http(s), Ping or keywords, every 5+ minutes
• opsgenie.com — Alert management with mobile push. 600 free alerts/month for 2 users
• runscope.com — Monitor and log API usage. Single user 25,000 requests/month free
• circonus.com — Free for 20 metrics
• uptimerobot.com — Website monitoring, 50 monitors free
• statuscake.com — Website monitoring, unlimited tests free with limitations
• bmc.com — Free 1 second resolution for up to 10 servers
• ghostinspector.com — Free website and web application monitoring. Single user, 100 test runs/month
• java-monitor.com — Free monitoring of JVM's and uptime
• sematext.com — Free for 24 hours metrics, unlimited number of servers, 10 custom metrics, 500 K custom metrics data points, unlimited dashboards, users, etc
• sealion.com — Free up to 2 servers, 3 days data retention, graphs and raw command output history (top, ps, ifconfig, netstat, iostat, free, custom, etc.)
• stathat.com — Get started with 10 stats for free, no expiration
• skylight.io — Free for first 100 K requests (Rails only)
• appdynamics.com — Free for 24 hours metrics, application performance management agents limited to one Java, one .NET, one PHP, and one Node.js
• deadmanssnitch.com — Monitoring for cron jobs. 1 free snitch (monitor), more if you refer others to sign up
• librato.com — Free up to 100 metrics at 60 seconds resolution
• freeboard.io — Free for public projects. Dashboards for your Internet of Things projects
• loader.io — Free load testing tools with limitations
• speedchecker.xyz — Performance Monitoring API, checks Ping, DNS, etc
• blackfire.io — Blackfire is the SaaS-delivered Application Performance Solution. Free Hacker plan (PHP Only)
• apimetrics.io — Automated API Performance Monitoring, Testing and Analytics. Free Plan, manually make API calls and Run from their West Coast servers
• opsdash.com — Self-hoster server, clusters and services monitoring, free for 5 servers and 5 services

Crash and Exception Handling

• rollbar.com — Exception and error monitoring, free plan with 5,000 errors/month, unlimited users, 30 days retention
• bugsnag.com — Free for up to 2,000 errors/month after the initial trial
• airbrake.io — Automatically groups, organizes and notifies you about your application errors. Free plan with 7,200 errors/day, 1 user, 1 project, 2 days retention
• getsentry.com — Sentry tracks app exceptions in realtime, has a small free plan. Free, unrestricted use if self-hosted

Search

• algolia.com — Hosted search-as-you-type (instant). Free hacker plan up to 10,000 documents and 100,000 operations. Bigger free plans available for community/Open Source projects
• swiftype.com — Hosted search solution (API and crawler). Free for a single search engine with up to 1,000 documents. Free upgrade to Premium level for Open Source
• bonsai.io — Free 1 GB memory and 1 GB storage
• searchly.com — Free 2 indices and 5 MB storage
• facetflow.com — Hosted Elasticsearch for Microsoft Azure. Free 5,000 docs and 500 MB
• indexisto.com — Site search reinvented. Free 10 million document index limit with advertisement block

Email

• sparkpost.com — First 100,000 emails/month are free
• mailgun.com — First 10,000 emails/month are free
• tinyletter.com — 5,000 subscribers/month are free
• mailchimp.com — 2,000 subscribers and 12,000 emails/month are free
• sendloop.com — 2,000 subscribers and 10,000 emails/month are free
• sendgrid.com — 400 emails/day for free and 25,000 free transactional emails/month for emails sent from a Google compute instance or Microsoft Azure App Service
• phplist.com — Hosted version allow 300 emails/month for free
• mailjet.com — 6,000 emails/month for free
• sendinblue.com — 9,000 emails/month for free
• mailtrap.io — Fake SMTP server for development, free plan with 1 inbox, 50 messages, no team member, 2 emails/second, no forward rules
• mailstache.io — 4 mailboxes with 1 GB each for up to 2 custom domains
• postmarkapp.com — First 25,000 emails are free
• zoho.com — Free email management and collaboration for up to 10 users
• domain.yandex.com — Free email and DNS hosting for up to 1,000 users
• pawnmail.com — 2 GB free email hosting across unlimited users for custom domain. Roundcube webmail, POP3, IMAP, and SMTP access. No paid plans or upgrades
• moosend.com — Mailing list management service. Free account for 6 months for startups
• debugmail.io — Easy to use testing mail server for developers
• mailboxlayer.com — Email validation and verification JSON API for developers. 1,000 free API requests/month
• mailcatcher.me — Catches mail and serves it through a web interface
• yopmail.fr — Disposable email addresses
• kickbox.io — Verify 100 emails free, real time API available
• inumbo.com — SMTP based spam filter, free for 10 users
• biz.mail.ru — 5,000 mailboxes with 25 GB each per custom domain with DNS hosting
• maildocker.com — First 10,000 emails/month are free
• sendpulse.com — 50 emails free/hour, first 12,000 emails/month are free
• pepipost.com — Unlimited emails free for first three months, then first 25,000 emails/month are free

CDN and Protection

• kloudsec.com — Minimal CDN platform targeted at programmers. CDN is free. Optional and free plugins include Page Optimization (Pagespeed), Service Doctor (Website performance analytics and alerts) and One-click Encryption (Auto provision/renew LetsEncrypt certs for HTTPS)
• cloudflare.com — Basic service is free, good for a blog, Cloudflare also offers a free SSL certificate service
• bootstrapcdn.com — CDN for bootstrap, bootswatch and font awesome
• surge.sh — Single–command, bring your own source control web publishing CDN
• cdnjs.com — CDN for JavaScript libraries, CSS libraries, SWF, images, etc
• jsdelivr.com — Super-fast CDN of OSS (JS, CSS, fonts) for developers and webmasters, accepts PRs to add more
• developers.google.com — The Google Hosted Libraries is a content distribution network for the most popular, Open Source JavaScript libraries
• asp.net — The Microsoft Ajax CDN hosts popular third party JavaScript libraries such as jQuery and enables you to easily add them to your Web application
• toranproxy.com — Proxy for Packagist and GitHub. Never fail CD. Free for personal use, 1 developer, no support
• rawgit.com — Free limited traffic, serves raw files directly from GitHub with proper Content-Type headers
• incapsula.com — Free CDN and DDoS protection
• fastly.com — Free CDN, all features until USD 50/month is reached, enough for most, then pay or suspended
• athenalayer.com — Free DDoS protection with unlimited websites
• section.io — A simple way to spin up and manage a complete Varnish Cache solution. Supposedly free forever for one site
• netdepot.com — First 100 GB free/month
• dropigee.com — Dropigee provides CDN + Cloud Storage, get 2 GB of bandwidth and unlimited storage free per month

PaaS

• cloud.google.com — Google App Engine gives 28 instance hours/day free, 1 GB NoSQL database and more
• engineyard.com — Engine Yard provides 500 free hours
• azure.microsoft.com — MS Azure gives USD 200 worth of free usage for a trial
• appharbor.com — A .Net PaaS that provides 1 free worker
• shellycloud.com — Platform for hosting Ruby and Ruby on Rails apps, €20 of free credit
• heroku.com — Host your apps in the cloud, free for single process apps
• firebase.com — Build realtime apps, free plan has 100 max. connections, 10 GB data transfer, 1 GB data storage, 1 GB hosting storage and 100 GB hosting transfer
• bluemix.net — IBM PaaS with a monthly free allowance
• openshift.com — Red Hat PaaS, free tier provides three small gears each with 512 MB memory and 1 GB storage. {Browse one-click deployments}
• outsystems.com — Enterprise web development PaaS for on-premise or cloud, free "personal environment" offering allows for unlimited code and up to 1 GB database
• platform.telerik.com — Build and deploy mobile applications using JavaScript. Free plan has 100 MB data storage, 1 GB file storage, 5 GB bandwidth, 1 million push notifications for BaaS offering, 100 active devices for analytics
• scn.sap.com — The in-memory Platform-as-a-Service offering from SAP. Free developer accounts come with 1 GB structured, 1 GB unstructured, 1 GB of Git data and allow you to run HTML5, Java and HANA XS apps
• mendix.com — Rapid Application Development for Enterprises, unlimited number of free sandbox environments supporting 10 users, 100 MB of files and 100 MB database storage each
• pythonanywhere.com — Cloud Python app hosting. Beginner account is free, 1 Python web application at your-username.pythonanywhere.com domain, 512 MB private file storage, one MySQL database
• configure.it — Mobile app development platform, free for 2 projects, limited features but no resource limits
• elastx.com — Free tier with up to 4 cloudlets, must be renewed every year
• pagodabox.io — Small worker, web server, cache, and database for free
• cloudandheat.com — 128 MB of RAM for free, includes support for custom domains for free

BaaS

• apigee.com — Unlimited trial includes NoSQL data store with 25 GB of storage, user and permission management, geolocation, 10 million push notifications/month, remote configuration, beta and A/B split testing, APM, fully API driven. Accessible and manageable via UI, SDK, and API
• appacitive.com — Mobile backend, free for the first 3 months with 100 K API calls, push notifications
• bip.io — A web-automation platform for easily connecting web services. Fully open GPLv3 to power the backend of your Open Source project. Commercial OEM License available
• blockspring.com — Cloud functions. Free for 5 million runs/month
• kinvey.com — Mobile backend, starter plan has unlimited requests/second, with 2 GB of data storage, as well as push notifications for up 5 million unique recipients. Enterprise application support
• konacloud.io — Web and Mobile Backend as a Service, with 5 GB free account
• layer.com — The full-stack building block for communications
• quickblox.com — A communication backend for instant messaging, video and voice calling, and push notifications
• pushbots.com — Push notification service. Free for up to 1.5 million pushes/month
• dreamfactory.com — DreamFactory is an Open Source backend platform that provides all of the RESTful services you need to build fantastic mobile and web applications
• onesignal.com — Unlimited free push notifications
• getstream.io — Build scalable news feeds and activity streams in a few hours instead of weeks, free for 3 million feed updates/month
• tyk.io — API management with authentication, quotas, monitoring, and analytics. Free cloud offering
• iron.io — Async task processing (like AWS Lambda) with free tier and 1 month free trial
• stackhut.com — Async task processing (like AWS Lambda). 10 free private services and unlimited free public services
• pubnub.com — Free push notifications for up to 1 million messages/month and 100 active daily devices
• webtask.io — Run code with an HTTP call. No provisioning. No deployment
• zapier.com — Connect the apps you use, to automate tasks. 5 zaps, every 15 min. and 100 tasks/month
• stackstorm.com — Event-driven automation for apps, services and workflows, free without flow, access control, LDAP,...
• simperium.com — Move data everywhere instantly and automatically, multi-platform, unlimited sending and storage of structured data, max. 2,500 users/month
• stamplay.com — Connect services together with a visual interface. 50 K API calls, 100 GB data transfer, and 1 GB storage for free

Web Hosting

• closeheat.com — Development Environment in the Cloud for Static Websites with Free Hosting and GitHub integration. 1 free website with custom domain support
• simplybuilt.com — SimplyBuilt offers free website building and hosting for {Open Source projects}. Simple alternative to GitHub Pages
• devport.co — Turn GitHub projects, apps, and websites into a personal developer portfolio
• netlify.com — Builds, deploy and hosts static site or app, free for 100 MB data and 1 GB bandwidth
• pantheon.io — Drupal and WordPress hosting, automated DevOps, and scalable infrastructure. Free for developers and agencies
• acquia.com — Hosting for Drupal sites. Free tier for developers. Free development tools (such as Acquia Dev Desktop) also available
• bitballoon.com — BitBalloon offers hosting for static sites and apps. Free on a subdomain
• readthedocs.org — Free documentation hosting with versioning, PDF generation and more
• bubble.is — Visual programming to build web and mobile apps without code, free 100 visitors/month, 2 apps
• contentful.com — Content as a Service. Content management and delivery APIs in the cloud. 3 users, 3 spaces (repositories) and 100,000 API requests/month for free
• tilda.cc — One site, 50 pages, 50 MB storage, only the main pre-defined blocks among 170+ available, no fonts, no favicon and no custom domain

DNS

• freedns.afraid.org — Free DNS hosting
• dns.he.net — Free DNS hosting service with Dynamic DNS Support
• luadns.com — Free DNS hosting, 3 domains, all features with reasonable limits
• domain.yandex.com — Free email and DNS hosting for up to 1,000 users
• cloudns.net — Free DNS hosting up to 3 domains with unlimited records
• ns1.com — Data Driven DNS, automatic traffic management, 1 million free queries

IaaS

• aws.amazon.com — AWS Free Tier, free for 12 months
• exoscale.ch — Free resources for Open Source
• developer.rackspace.com — Rackspace Cloud gives USD 50/month for 12 months
• cloud.google.com/compute — Google Compute Engine gives USD 300 over 60 days
• virtzone.net — Free VPS. You must meet certain minor qualifications

DBaaS

• cloudant.com — Hosted database from IBM, free if usage is below USD 50/month
• orchestrate.io — 1 application free
• redislabs.com — Redis as a Service, 30 MB and 30 concurrent connections free
• backand.com — Back-end as a service for AngularJS
• zenginehq.com — Build business workflow apps in minutes, free for single users
• redsmin.com — Online real-time monitoring and administration service for Redis, 1 Redis instance free
• graphstory.com — GraphStory offers Neo4j (a Graph Database) as a service
• elephantsql.com — PostgreSQL as a service, 20 MB free
• graphenedb.com — Neo4j as a service, up to 1,000 nodes and 10,000 relations free
• mongolab.com — MongoDB as a service, 500 MB free
• scalingo.com — Primarily a PaaS but offers a 512 MB free tier of MySQL, PostgreSQL, or MongoDB
• skyvia.com — Cloud Data Platform, offers free tier and all plans are completely free while in beta
• airtable.com — Looks like a spreadsheet, but it's a relational database, unlimited bases, 1,200 rows/base and 1,000 API requests/month
• fieldbook.com — Fieldbook lets anyone create a simple tracking database, as easily as a spreadsheet. Automatic API. Unlimited free sheets, share with unlimited users
• iriscouch.com — CouchDB as a service. Free for developing, prototyping, etc

STUN, WebRTC, Web Socket Servers and Other Routers

• pusher.com — Hosted Web Sockets broker. Free for up to 20 simultaneous connections and 100 K messages/day
• stun:stun.l.google.com:19302 — Google STUN
• stun:global.stun.twilio.com:3478?transport=udp — Twilio STUN
• segment.com — Hub to translate and route events to other third party services. 100 K events/month free
• ngrok.com — Expose locally running servers over a tunnel to a public URL
• cloudamqp.com — RabbitMQ as a Service. Little Lemur plan: max 1 million messages/month, max 20 concurrent connections, max 100 queues, max 10,000 queued messages, multiple nodes in different AZ's

Issue Tracking and Project Management

• bitrix24.com — Free intranet and project management tool
• pivotaltracker.com — Pivotal Tracker, free for public projects
• atlassian.com — Free Jira etc for Open Source
• kanbantool.com — Kanban board based project management. Free, paid plans with more options
• kanbanflow.com — Board based project management. Free, premium version with more options
• kanbanery.com — Board based project management. Free for 2 users, premium tiers with more options
• zenhub.io — The only project management solution inside GitHub. Free for public repos, OSS, and nonprofits organizations
• trello.com — Board based project management. Free
• producteev.com — Task management tool. Free, premium version with more options. Mobile applications available
• fogcreek.com — Bug tracking and project management. Free for 2 users
• waffle.io — Board based project management solution from your existing GitHub Issues, free for Open Source
• huboard.com — Instant project management for your GitHub issues, free for Open Source
• taiga.io — Project management platform for startups and agile developers, free for Open Source
• jetbrains.com — Free hosted YouTrack (InCloud) for FOSS projects, private projects {free for 10 users}
• github.com — In addition to its Git storage facility, GitHub offers basic issue tracking
• asana.com — Free for private project with collaborators
• acunote.com — Free project management and SCRUM software for up to 5 team members
• gliffy.com — Online diagrams: flowchart, UML, wireframe,... Also plugins for Jira & Confluence. 5 diagrams and 2 MB free
• cacoo.com — Online diagrams in real time: flowchart, UML, network. Free max. 15 users/diagram, 25 sheets
• draw.io — Online diagrams stored locally, in Google Drive, OneDrive or Dropbox. Free for all features and storage levels
• hub.jazz.net — IBM Bluemix's project management services. Free for public projects, free for up to 3 users for private projects
• leankit.com — Kanban board, that visualizes your workflow. Free up to 10 users
• visualstudio.com — Unlimited free private code repositories; Tracks bugs, work items, feedback and more
• testlio.com — Issue tracking, test management and beta testing platform. Free for private use
• vivifyscrum.com — Free tool for Agile project management. Scrum Compatible
• targetprocess.com — Visual project management, from Kanban and Scrum to almost any operational process. Free for unlimited users, up to 1,000 data entities {more details}
• overv.io — Agile project management for teams who love GitHub
• taskulu.com — Role based project management. Free up to 5 users. Integration with GitHub/Trello/Dropbox/Google Drive
• contriber.com — Customizable project management platform, free starter plan, 5 workspaces
• planitpoker.com — Free online planning poker (estimation tool)

Storage and Media Processing

• aerofs.com — P2P file syncing, free for up to 30 users
• bintray.com — Binary File storage, free for Open Source. Includes SSL, CDN and a limited number of REST calls
• cloudinary.com — Image upload, powerful manipulations, storage, and delivery for sites and apps, with libraries for Ruby, Python, Java, PHP, Objective-C and more. Perpetual free tier includes 7,500 images/month, 2 GB storage, 5 GB bandwidth
• plot.ly — Graph and share your data. Free tier includes unlimited public files and 10 private files
• transloadit.com — Handles file uploads & encoding of video, audio, images, documents. Free for Open Source & other do-gooders. Commercial applications get one GB free for test driving
• podio.com — You can use Podio with a team of up to five people and try out the features of the Basic Plan, except users management
• shrinkray.io — Free image optimization of GitHub repos
• imagefly.io — Responsive images on-demand. CDN fronted image resizing, transcoding, and optimizing. 100 MB/month for free
• kraken.io — Image optimization for website performance as a service, free plan up to 1 MB file size
• placehold.it — A quick and simple image placeholder service
• placekitten.com — A quick and simple service for getting pictures of kittens for use as placeholders
• placepenguin.com — A quick and simple service for placeholder images of penguins
• embed.ly — Provides APIs for embedding media in a webpage, responsive image scaling, extracting elements from a webpage. Free for up to 5,000 URLs/month at 15 requests/second
• backhub.co — Backup and archive your GitHub repositories. Free for public repos
• otixo.com — Encrypt, share, copy and move all your cloud storage files from one place. Basic plan provides unlimited files transfer with 250 MB max. file size and allows 5 encrypted files
• tinypng.com — API to compress and resize PNG and JPEG images, offers 500 compressions for free each month
• filestack.com — File picker, transform and deliver, free for 250 files, 500 transformations and 3 GB bandwidth

Design and UI

• pixlr.com — Free online browser editor on the level of commercial ones
• imagebin.ca — Pastebin for images
• cloudconvert.com — Convert anything to anything. 208 supported formats including videos to gif
• resizeappicon.com — A simple service to resize and manage your app icons
• vectr.com — Free Design App For Web + Desktop
• walkme.com — Enterprise Class Guidance and Engagement Platform, free plan 3 walk-thrus up to 5 steps/walk
• marvelapp.com — Design, prototyping and collaboration, free limited for 3 projects

Data Visualization on Maps

• geocod.io — Geocoding via API or CSV Upload. 2,500 free queries/day
• gogeo.io — Maps and geospatial services with an easy to use API and support for big data
• cartodb.com — Create maps and geospatial APIs from your data and public data
• giscloud.com — Visualize, analyze and share geo data online
• latlon.io — Geocoding API + school districts, census geography divisons, and other address based data. 2,500 free requests/month
• mapbox.com — Maps, geospatial services, and SDKs for displaying map data

Package Build System

• build.opensuse.org — Package build service for multiple distros (SUSE, EL, Fedora, Debian etc.)
• copr.fedoraproject.org — Mock-based RPM build service for Fedora and EL
• help.launchpad.net — Ubuntu and Debian build service

IDE and Code Editing

• c9.io — IDE in a browser. Incorporates an Ubuntu virtual machine and in-browser terminal access. Integrates with GitHub and BitBucket, but also adds SFTP and generic Git access
• codeanywhere.com — Full IDE in the browser and mobile apps. Access FTP, SFTP, Dropbox, Google Drive, GitHub, and BitBucket. Hosted virtual machines with terminal access. Collaboration features like share links, live editing, permissions, and version tracking
• codenvy.com — IDE and automated developer workspaces in a browser, collaborative, Git/SVN integration, build and run your app in customizable Docker-based runners (free tier includes: 4 GB RAM, always-on machines, ability to run multiple machines simultaneously), pre-integrated deploy to Google Apps
• nitrous.io — Private Linux instance(s) with interactive collaboration, free for 2 hours/day. {More Details}
• visualstudio.com — Fully-featured IDE with thousands of extensions, cross-platform app development (Microsoft extensions available for download for iOS and Android), desktop, web and cloud development, multi-language support (C#, C++, JavaScript, Python, PHP and more)
• code.visualstudio.com — Build and debug modern web and cloud applications. Code is free, Open Source and available on your favorite platform, Linux, Mac OSX and Windows
• cloud.sagemath.com — Collaborative mathematics-oriented IDE in a browser, with support for Python, LaTeX, IPython Notebooks, etc
• wakatime.com — Quantified self metrics about your coding activity, using text editor plugins, limited plan for free
• apiary.io — Collaborative design API with instant API mock and generated documentation (Free for unlimited API blueprints and unlimited user with one admin account and hosted documentation)
• mockable.io — Mockable is a simple configurable service to mock out RESTful API or SOAP web-services. This online service allows you to quickly define REST API or SOAP endpoints and have them return JSON or XML data
• jetbrains.com — Productivity tools, IDEs and deploy tools. Free license for students, teachers, Open Source, and user groups
• stackhive.com — Cloud based IDE in browser that supports HTML5/CSS3/jQuery/Bootstrap
• tadpoledb.com — IDE in browser Database tool. Support Amazon RDS, Apache Hive, Apache Tajo, CUBRID, MariaDB, MySQL, Oracle, SQLite, MSSQL, PostgreSQL and MongoDB databases
• sourcelair.com — In-browser IDE for Django, JavaScript, HTML5, Python, and more. Integrates with Git, Mercurial, GitHub, Heroku and more. Free forever for 1 private project
• codepen.io — CodePen is a playground for the front end side of the web

Analytics, Events and Statistics

• analytics.google.com — Google Analytics
• heapanalytics.com — Automatically captures every user action in iOS or web apps. Free for up to 5,000 visits/month
• sematext.com — Free for up to 50 K actions/month, 1 day data retention, unlimited dashboards, users, etc
• usabilityhub.com — Test designs and mockups on real people, track visitors. Free for one user, unlimited tests
• gosquared.com — Track up to 1,000 data points for free
• mixpanel.com — Free 25,000 points or 200,000 with their badge on your site
• amplitude.com — 1 million monthly events, up to 2 apps
• keen.io — Custom Analytics for data collection, analysis and visualization. 50,000 events/month free
• inspectlet.com — 100 sessions/month free for 1 website
• mousestats.com — 100 sessions/month free for 1 website
• metrica.yandex.com — Unlimited free analytics
• hotjar.com — Per site: 2,000 pages views/day, 3 heatmaps, data stored for 3 months,...
• imprace.com — Landing page analysis with suggestions to improve bounce rates. Free for 5 landing pages/domain
• baremetrics.com — Analytics & Insights for stripe
• optimizely.com — A/B Testing solution, free starter plan, 1 website, 1 iOS and 1 Android app
• expensify.com — Expense reporting, free personal reporting approval workflow

International Mobile Number Verification API and SDK

• cognalys.com — Freemium mobile number verification through an innovative and reliable method than using SMS gateway. Free accounts will have 70 tries and 50 verifications/day. {Signup}
• numverify.com — Global phone number validation & lookup JSON API. 250 API requests/month
• sumome.com — Heat map and conversion enhancement tools, free without few advanced features

Payment / Billing Integration

• braintreepayments.com — Credit Card, Paypal, Venmo, Bitcoin, Apple Pay,... integration. Single and Recurrent Payments. First USD 50,000 are free of charge
• taxratesapi.avalara.com — Get the right sales tax rates to charge for the close to 10,000 sales tax jurisdictions in the USA. Free REST API. Registration required
• currencylayer.com — Reliable Exchange Rates & Currency Conversion for your Business, 1,000 API requests/month free
• vatlayer.com — Instant VAT number validation & EU VAT rates API, free 100 API requests/month

Docker Related

• quay.io — Unlimited free public repositories
• tutum.co — The Docker Platform for Dev and Ops, build, deploy, and manage your apps across any cloud, free while in beta and free developer plan when tutum will be production ready

Vagrant Related

• atlas.hashicorp.com — HashiCorp's index of boxes
• vagrantbox.es — An alternative public box index

Miscellaneous

• apichangelog.com — Subscribe to be notified each time API Documentation is updated (Facebook, Twitter, Google,...)
• instadiff.com — Compare website versions with highlighted changes before you deploy, free for 100 pages/month
• fullcontact.com — Help your users know more about their contacts by adding social profile into your app. 500 free Person API matches/month
• apicastor.com — Convert spreadsheets into URL and monitor access
• formlets.com — Online forms, unlimited single page forms/month, 100 submissions/month, email notifications
• superfeedr.com — Real-time PubSubHubbub compliant feeds, export, analytics. Free with less customization
• screenshotlayer.com — Capture highly customizable snapshots of any website. Free 100 snapshots/month
• readme.io — Beautiful documentations made easy, free for Open Source

APIs, Data, and ML

• monkeylearn.com — Text analysis with Machine Learning, free 100,000 queries/month
• wit.ai — NLP for developers
• wolfram.com — Built-in knowledge based algorithms in the cloud
• parsehub.com — Extract data from dynamic sites, turn dynamic websites into APIs, 5 projects free
• import.io — Easily turn websites into APIs, completely free for life
• wrapapi.com — Turn any website into a parameterized API
• algorithmia.com — Host algorithms for free. Includes free monthly allowance for running algorithms. Now with CLI support
• bigml.com — Hosted machine learning algorithms. Unlimited free tasks for development, limit of 16 MB data/task
• mashape.com — API Marketplace And Powerful Tools For Private And Public APIs. With the free tier, some features are limited such as monitoring, alerting and support
• dominodatalab.com — Data science with support for Python, R, Spark, Hadoop, Matlab, and others
• havenondemand.com — APIs for machine learning
• restlet.com — APISpark enables any API, application or data owner to become an API provider in minutes via an intuitive browser interface
• scrapinghub.com — Data scraping with visual interface and plugins. Free plan includes unlimited scraping on a shared server

Other Free Resources

• github.com - FOSS for Dev — A hub of free and Open Source software for developers
• github.com - Free for nonprofit — List of free services for nonprofit organizations
• getawesomeness — Retrieve all amazing awesomeness from GitHub... a must see
• education.github.com — Collection of free services for students. Registration required