Server frameworks, APIs, languages
Simplified analytics release workflow. Single-source-of-truth tracking plan, type-safe analytics tracking library, in-app debuggers, and data observability to catch all data issues before you release. Free for two workspace members and 1 hour data observability lookback.
Automatically captures every user action in iOS or web apps. Free for up to 10K monthly sessions.
Simple analytics for people managing lots of sites. Install manually or let Claude/Cursor do it for you. Free for up to 10k events/month.
An easy-to-use currency conversion JSON API. The free tier updates once per day with a limit of 1,500 requests/month.
Privacy-focused, cookie-free analytics, free for up to 3k events/month.
AppFit is a comprehensive analytics and product management tool designed to facilitate seamless, cross-platform management of analytics and product updates. Free plan includes 10,000 events per month, product journal and weekly insights.
Beampipe is simple, privacy-focussed web analytics. free for up to 5 domains & 10k monthly page views.
Free currency conversion and exchange rate data API. Free 300 requests per month, 10 requests per minute for private use.
Reliable Exchange Rates and Currency Conversion for your Business, 100 API requests/month free.
Real-time currency rates for 160+ currencies with 60-second updates and official SDKs. Free tier includes 300 requests/month.
Instant VAT number validation and EU VAT rates API, free 100 API requests/month
Reverse ETL & Operational Analytics Platform. Sync 10 fields from your data warehouse to 60+ SaaS like Salesforce, Zendesk, or Amplitude.
All-in-one platform spanning across analytics, feature flagging, and A/B testing. Free for up to 1m metered events per month.
AI Analytics for E-commerce. Ask questions in natural language about your analytics, get actionable recommendations and grow your revenue with AI-powered insights. Free for up to 10k events per month.
Hightouch is a Reverse ETL platform that helps you sync customer data from your data warehouse to your CRM, marketing, and support tools. The free tier offers you one destination to sync data to.
Live Currency Rates for Physical and Cryptocurrencies, delivered in JSON and XML. The free tier offers 1,250 API requests/month.
Test designs and mockups on real people and track visitors. Free for one user, unlimited tests
Global phone number verification in a free, fast, reliable JSON API. 1000 requests/month
Cancel flows (open-sourced), churn metrics, and revenue analytics for subscription businesses. Free forever.
Help merchants to prevent payment fraud and chargebacks. Free Micro Plan available with 500 queries/month.
All-in-one cross-platform subscription management platform offering analytics, A/B testing, Apple Search Ads, remote configs, and growth tools for optimizing in-app purchases and monetization. Compatible with iOS, Android, React Native, Flutter, Unity, Cordova, Stripe, and web. Free up to $10k in mo
Privacy-focused, open-source web and product analytics platform with a free cloud plan for 3 websites, 3 team members, 60-day data retention, AI analytics, goals, funnels, events, and hits.
Website Viewer Analytics. Free plan for analytics of 500 most recent visitors.
Automatically adjust pricing based on visitor location to expand your business globally and reach new markets (purchasing power parity). The free plan includes 7,500 API requests/month.
Web analytics made simple and therefore privacy friendly. Free or pay what you want by donation.
Website Analytics and Reports . Free Plan allows 2000 pageviews/day. One hundred snapshots/day (max capacity: 300). Three snapshot heatmaps can be stored for 365 days. Unlimited Team Members. Also in App and standalone surveys, feedback widgets with screenshots. Free tier allows creating 3 surveys &
Full unified web and product analytics platform, including embeddable analytics widgets and automated robots (slack, telegram, and webhooks). Free plan includes 10,000 events per month.
100,000 monthly tracked users, unlimited data history and seats, US or EU data residency
Provides current and historical currency exchange rates. Free DEVELOPER plan available with 1000 requests/month.
Provides real-time and historical exchange rates. The free tier requires attribution.
Blazingly fast, connected spreadsheet. Connect directly to data databases, S3, and APIs. Import, analyze, graph, and share millions of rows instantly. Three free (forever) workbooks.
Open Source, Privacy-Friendly, and Simple Analytics for Mobile and Desktop Apps. SDKs for Swift, Kotlin, React Native, Flutter, Electron, and many others. Free for up to 20,000 events per month.
Provides cryptocurrency market data including the latest crypto and fiat currency exchange rates. The free tier offers 10K call credits/month.
Generate revenue from APIs via usage-based billing. Connect to Stripe, Chargebee, etc. The free tier offers 30,000 events/month.
Secure document sharing with document tracking and engagement Analytics. Free plan supports up to 20 PDF documents (10 MB max), 10 contacts, and 2 shares per document with basic analytics for views downloads, time and engagement.
GoatCounter is an open-source web analytics platform available as a hosted service (free for non-commercial use) or self-hosted app. It aims to offer easy-to-use and meaningful privacy-friendly web analytics as an alternative to Google Analytics or Matomo. The free tier is for non-commercial use and
Hosted backend for in-app purchases and subscriptions (iOS and Android). Free up to $2.5k/mo in tracked revenue.
Automatically detect digital analytics, marketing data and pixels issues, maintain up-to-date tracking plans, and foster seamless collaboration. Deploy it to your production environment with real traffic or add analytics coverage to your regression tests without writing code.
Free lightweight privacy-focused alternative to Google Analytics. Unlimited pageviews, unlimited visitor, unlimited page heatmaps & goal tracking. Free for up to 3 domains and 600 session replay per domain.
Beautiful dashboard for tracking GitHub repo traffic history longer than 14 days. Free Plan allows users to monitor traffic for a single repository.
One-stop solution with open-source SDK for mobile in-app subscription integration to iOS, Android, React Native, Flutter, Unity, or web app. Free up to $10k monthly revenue.
Full Product Analytics suite free for up to 1m tracked events per month. Also provides unlimited in-App Surveys with 250/month responses.
Seline is a simple & private website and product analytics. Cookieless, lightweight, independent. Free plan includes 3,000 events per month and provides access to all our features, such as the dashboard, user journeys, funnels, and more.
Real-time mid-market exchange rates for 150+ currencies with official JavaScript, Python, and PHP SDKs. Free tier includes 300 requests/month over HTTPS.
Open-source and cookieless alternative to Google Analytics that is 10x more intuitive. Free plans has 3,000 monthly events.
Multi-protocol tunneling for HTTP, TLS, TCP, UDP, File Server (Default, SFTP, WebDAV), and Proxy Tunnel (HTTP, SOCKS5, Shadowsocks, VLESS). Free plan: 1 tunnel, 1GB/month bandwidth, 30 min timeout (excl. HTTP Tunnels).
Expose locally running servers over a tunnel to a public URL. Free hosted version, and [open source](https://github.com/localtunnel/localtunnel).
Expose local servers to the internet. No installation, no signup. Free subdomain, no limits.
Connect multiple computers together via a VPN-enabling LAN-like network. Unlimited peers. (Hamachi alternative)
Public URLs for localhost with a single command, no downloads required. HTTPS / TCP / TLS tunnels. The free plan has 60 minutes tunnel lifetime.
Manage, debug, fan-out, and proxy all your webhooks to public or internal (i.e. localhost) destinations. Also, expose servers running in a private network over a tunnel by getting a public HTTP endpoint (`https://yoursubdomain.webrelay.io http://localhost:8080`).
Zero config VPN, using the open-source WireGuard protocol. Installs on MacOS, iOS, Windows, Linux, and Android devices. Free plan for personal use with 100 devices and three users.
Develop, test, and monitor your webhooks from anywhere. 100K requests and 100K attempts per month with three days retention.
Unlimited STUN usage + 500 MB monthly TURN bandwidth, capped bandwidth, single geographic region.
FOSS managed virtual Ethernet as a service. Unlimited end-to-end encrypted networks of 25 clients on the free plan. Clients for desktop/mobile/NA; web interface for configuration of custom routing rules and approval of new client nodes on private networks
Reverse proxy that enables you to expose your localhost servers to the internet. The free plan has 15 minutes tunnel lifetime.
Free push notifications for up to 1 million messages/month and 100 active daily devices
Expose local sites via secure tunnels. The free plan includes an EU Server, Random subdomains, and Single users.
The Open Source Firebase Alternative to build backends. Free Plan offers Authentication, Realtime Database & Object Storage.
Backend service API with flexible authentication, full-text search and caching. Free for one app, 1GB of app data.
Move data everywhere instantly and automatically, multi-platform, unlimited sending and storage of structured data, max. 2,500 users/month
LogMeIn Hamachi is a hosted VPN service that lets you securely extend LAN-like networks to distributed teams with a free plan that allows unlimited networks with up to 5 people
API management with authentication, quotas, monitoring and analytics. Free cloud offering
Free, unlimited push notifications for 2000 monthly active users. A single API for iOS and Android devices.
Connect the apps you use to automate tasks. Five zaps every 15 minutes and 100 tasks/month
Visual Studio extension to expose IIS Express to the local network or over a tunnel to a public URL.
Expose localhost and local tcp server to the internet. Free plan includes file server, custom http request and response headers, basic auth protection and 1 hour tunnel timeout.
Build your Flutter App UI without writing a single line of code. Also has a Firebase integration. The free plan includes full access to UI Builder and Free templates.
Unlimited chat messages, p2p voice & video calls, files attachments and push notifications. Free for apps up to 1000 users.
Back4App is an easy-to-use, flexible and scalable backend based on Parse Platform.
Reactive backend as a service, hosting your data (documents with relationships & serializable ACID transactions), serverless functions, and WebSockets to stream updates to various clients. Free for small projects - up to 1M records, 5M monthly function calls.
Unlimited free push notifications. 10,000 email sends per month, with unlimited contacts and access to Auto Warm Up.
Build automation flows to connect several apps together in your app's backend. For example, send a Slack message or add a Google Sheet row when an event fires in your app. Free up to 5,000 tasks per month.
Build scalable In-App Chat, Messaging, Video and audio, and Feeds in a few hours instead of weeks
Serverless backend for web and mobile apps. The free plan includes PostgreSQL, GraphQL (Hasura), Authentication, Storage, and Serverless Functions.
Mobile backend. 1GB of data storage, 256MB instance, 3K API requests/day, and 10K pushes/day are free. (API is very similar to Parse Platform)
Define, version, and deploy automation scripts using YAML. A developer-first alternative to drag-and-drop tools. Can be used for scheduled tasks, AI agents, and infrastructure monitoring. Free tier includes 100 credits/month.
Mobile and Web Baas, with 1 GB file storage free, push notifications of 50,000/month, and 1000 data objects in the table.
10 API requests per hour for email verification, IP, and phone number validation in the free tier. No Credit Cards are required.
Test if the email's DNS/SPF/DKIM/DMARC settings are correct, 20 free/month.
Open source, anonymous email alias/forwarding solution with PGP encryption, reply capability, 10 random & 1 custom alias on the free plan with developer API & CLI.
SMTP relay and email API for developers. 5,000 emails per month, unlimited domains, free email verification, blacklist monitoring, mail tester and more.
Email API with REST API and SMTP integrations, free for upto 3,000 emails/month.
Up to 100 subscribers and unlimited emails as well as automations for free.
EU-hosted feature flag management with scheduled releases, instant rollback, and A/B testing. 12 SDKs included. Free plan up to 500K API requests/month, unlimited flags, 3 team members, no credit card required.
Email forwarding for custom domains with ARC/DKIM signing. Free plan includes 1 domain, 1 mailbox, 300 emails/month, and up to 1MB message size. Email receiving webhook also available. Special plans for open-source projects.
Release features with confidence; manage feature flags across web, mobile, and server-side applications. Use our hosted API, deploy to your own private cloud, or run on-premise.
Free email deliverability test with no signup. Generates a unique inbox address, then analyzes SPF, DKIM, DMARC, Rspamd spam score, 23+ RBL blacklists, reverse DNS, and content quality. Unlimited tests, results in seconds, shareable report pages.
Free secure email account service provider with built-in end-to-end encryption. Free 1GB storage.
Type-safe feature flags, A/B testing, analytics and app configuration, with Git-style version control and synchronous, in-memory, local flag evaluation. Free for up to 5 team members with unlimited feature flags and A/B tests.
Free 10 Email IDs, 1 Domain, 1 Mailbox. Single Mailbox for All Email IDs.
Email API, SMTP, 3,500 emails/month free for transactional and marketing emails. Email Sandbox - fake SMTP server for development, free plan with one inbox, 100 messages, no team member, two emails/second, no forward rules.
Open source feature flag and A/B testing provider with built-in Bayesian statistical analysis engine. Free for up to 3 users, unlimited feature flags and experiments.
Free API for temporary email testing, free public email hosting, outbound capture, email-to-slack/websocket/webhook (1,500 monthly API limit)
Up to 2 Email addresses under your domain for free with 100MB of storage space. IMAP, POP3, SMTP, SPF/DKIM support.
Test if the email's DNS/SPF/DKIM/DMARC settings are correct, free service by roundsphere.com
Open-source anonymous email forwarding, create unlimited email aliases for free
Block disposable emails, catch typos, and validate MX records via a simple API. 100 free requests/month.
Free disposable email addresses with forwarding and automatic address expiration
ConfigCat is a developer-centric feature flag service with unlimited team size, excellent support, and a reasonable price tag. Free plan up to 10 flags, two environments, 1 product, and 5 Million requests per month.
Enterprise-ready, scalable multi-regional feature toggles management platform. Free plan up to 10 flags, two environments, unlimited requests. SDK, analytics dashboard, release calendar, Slack notifications, and all other features are included in the endless free plan.
Free secure email account service provider with built-in end-to-end encryption, no ads, no tracking. Free 1GB storage, one calendar (Tuta also have an [paid plan](https://tuta.com/pricing).). Tuta is also partially [open source](https://github.com/tutao/tutanota), so you can self-host.
Transactional emails API for developers. 3,000 emails/month, 100 emails/day free, one custom domain.
A robust platform for feature management, A/B testing, analytics, and more. Its generous free plan offers unlimited seats, flags, experiments, and dynamic configurations, supporting up to 1 million events per month.
Ethereal is a fake SMTP service, mainly aimed at Nodemailer and EmailEngine users (but not limited to). It's an entirely free anti-transactional email service where messages never get delivered.
Free email infrastructure grader that checks SPF, DKIM, DMARC and mail server configuration. Scores any domain out of 100. No signup required.
This is not an entire email server; this is just an email client that you can use to send emails right from the client without exposing your credentials, the free tier has 200 monthly requests, 2 email templates, Requests up to 50Kb, Limited contacts history.
Open source, self-hostable email alias/forwarding solution. Free 10 Aliases, unlimited bandwidth, unlimited reply/send. Free for educational staff (student, researcher, etc.).
Transactional email service, free for 1000 emails per month, with unlimited domains, team members, webhooks and message routes in the free plan.
Free disposable temporary email service with multiple emails at once and forwarding
free 12,000 emails/month, Email API and SMTP, SPF/DKIM/DMARC support, No Credit Cards are required.
Email framework as a service, that adds templates, automations, history, etc to your own SMTP server (E.g. AWS, Maileroo, Gmail). Free up to 100 emails/day, no time limit.
Turn incoming emails into webhooks to trigger your API from emails. The service is completely free.
Prevent users to sign up with temporary email addresses, 120 requests/hour (~86,400 per month)
Email API, SMTP, 500 emails/month free for transactional emails, 100 API requests/day
Verify up to 200 emails a month for free and see if an email is temporary or not.
Temporary / Disposable Mail Gen Utilizing a range variety of domain. Email Address refreshes everytime, the page is reloaded. It is entirely free and does not include any pricing for their services.
A user-friendly DMARC monitoring platform. The free plan covers one domain with up to 1,000 emails per month.
Create up to 3 temporary emails a day, then delete them when you're done from within a handy Chrome extension. Perfect for testing signup flows.
Open-Source feature flags & A/B testing. Configuration as Code & Fully Typed Typescript SDKs. Strong integration with Frameworks such as Next.js & React. Generous free tier and cheap scaling options.
Free email forwarding for custom domains. Create and forward an unlimited amount of email addresses with your domain name (note: You must pay if you use .casa, .cf, .click, .email, .fit, .ga, .gdn, .gq, .lat, .loan, .london, .men, .ml, .pl, .rest, .ru, .tk, .top, .work TLDs due to spam)
Sandbox Email Server for testing email functionality across build/qa and ci/cd. Free accounts get 15 emails a day forever.
Waitlist management software for product launches. Create branded waitlist pages, collect and verify email subscribers, manage signups with tags and analytics. Free plan includes 100 subscribers/month, 1 waitlist, and API access.
Real-time email verification API with mailbox confirmation and disposable email address detector; 25 free email verifications/day.
Free temporary/disposable email inbox, with up to 3-day email auto-deletes. Open source and can be self-hosted.
Multi-channel notification infrastructure for developers with a prebuilt in-app inbox and no-code template editor. Free plan includes 10,000 messages/mo.
The open-source notification infrastructure for developers. Simple components and APIs for managing all communication channels in one place: Email, SMS, Direct, In-App and Push. The free plan includes 30,000 notifications/month with 90 days of retention.
Communication infrastructure in 5 minutes. Free tier includes: 100 SMS and calls, 3000 Emails, Push, Slack, MS Teams, WhatsApp, and more.
Realtime messaging service with presence, persistence and guaranteed delivery. The free plan includes 3m messages per month, 100 peak connections, and 100 peak channels.
All-in-one Customer Engagement and Automation Tool (email, push, SMS, product tours, banners and more) for SaaS. Free for up to 1,000 active users per month.
Realtime messaging service, Pusher-compatible. Dev tier is limited to local development only and free with 100 concurrent connections, 1,000,000 broadcasts/month, unlimited client events, 32kb message size.
SuprSend is a notification infrastructure that streamlines your product notifications with an API-first approach. Create and deliver transactional, crons, and engagement notifications on multiple channels with a single notification API. In free plan you get 10,000 notifications per month, including
Notifications infrastructure for developers. Send to multiple channels like in-app, email, SMS, Slack, and push with a single API call. The free plan includes 10,000 messages/mo.
Send and receive text messages using your Android phone as an SMS Gateway. Free to send and receive up to 200 messages per month.
Connect your MQTT devices to the Cloud Native IoT Messaging Broker. Free to connect up to 100 devices (no credit card required) forever.
Send push notifications to your iOS and Android devices. Effortlessly integrate via API or Webhooks and maintain full control over your alerts. Free plan: 50 messages per day to 1 device and 1 application.
Realtime messaging service. Free for up to 100 simultaneous connections and 200,000 messages/day
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
Single API for push, in-app, email, chat, SMS, and other messaging channels with template management and other features. The free plan includes 10,000 messages/mo.
Realtime messaging service. Free for up to 20 simultaneous connections and 100,000 events/day
SMS Gateway for Android™ enables sending and receiving SMS messages through your devices using cloud routing. Completely free cloud service (with recommended notification for usage above 10,000 messages/day to maintain quality for all users).
[NATS.io](https://nats.io) as a service. Global, AWS, GCP, and Azure. Free forever with 4k msg size, 50 active connections, and 5GB of data per month.
Web Push Notifications - Free for upto 10k subscribers, unlimited push notifications, in-browser messaging
Scalable and secure serverless MQTT broker you can get in seconds. 1M session minutes/month free forever (no credit card required).
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