No moat. Still in business.

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Make your own flashcard decks and review them on a spaced repetition schedule in the browser.

Since 2015

Free plan · Courses and learning · Individuals and families

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Website live chat with an AI agent and one shared inbox for WhatsApp, Instagram, Messenger and email messages.

Since 2023Updated 15 days ago

Free plan · Customer support

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Pulls data out of recurring emails and attachments using your rules, then sends it to spreadsheets, CRMs or webhooks.

Since 2013

Free trial · Data and spreadsheets

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Open-source billing engine that meters usage, runs subscription and hybrid plans, and issues invoices for software firms.

Since 2021

Free · Invoicing and billing · Software companies

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Build hosted or embedded checkout pages to sell products, subscriptions, tickets and services through your own Stripe account.

Since 2018

Free plan · Payments and checkout · Online sellers

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Fires webhooks once or on a cron schedule in your timezone and alerts you when a call fails.

Since 2019

Free plan · Developer tools · Developers

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An ecommerce platform with an API for selling products and subscriptions, with custom storefronts and checkout, for online brands.

Since 2021

Free trial · Online shops · Shops and retail

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Build PDF templates in a visual or HTML editor, then fill them with data by API or Zapier to make invoices and other files.

Free plan · Documents and e-signature

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Posts a Slack alert when Apple or Google approves or rejects your app, or a TestFlight build is ready.

Since 2023

Subscription · Uptime and monitoring · Developers

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Helps students sort courses, tasks, class schedules, flashcards and files into colour-coded folders.

Free · Focus and productivity · Individuals and families

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Send your own HTML form to a hosted endpoint that stores entries, holds back spam and forwards them to email or other tools.

Forms and surveys · Agencies

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Jot tasks down quickly on iPhone or Mac and sort them into your other tools later.

Since 2024

Free plan · Projects and tasks · Individuals and families

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An iPhone app that takes Japanese learners from beginner to fluent with one new sentence per flashcard and spaced review.

Since 2015

Courses and learning · Individuals and families

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Lets support and sales staff browse any website together with a customer in real time, without installing code.

Since 2013

Customer support

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A browser extension that saves and highlights words you look up on web pages, then drills them with flashcards.

Since 2020

Free plan · Courses and learning · Individuals and families

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Desktop data analysis app where you ask about your data in plain English and get Python code, charts and notebooks run on your computer.

Since 2017

Data and spreadsheets

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Note app for students that builds flashcards, quizzes and summaries from notes and PDFs with spaced repetition.

Since 2021

Free plan · Courses and learning · Individuals and families

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A hosted service that sends your app's webhooks with retries, logs and debugging so developers need not build it.

Free plan · Developer tools · Developers

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Connect email accounts and get messages sent to your webhooks, with an API for replies and content analysis.

Since 2023

Free trial · Developer tools · Developers

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Sends webhooks from your app to customers with retries, signatures and logs, hosted in the EU or run on your own servers.

Free plan · Developer tools · Developers

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Students turn class notes or a PDF into a practice test that marks itself and explains each question they got wrong.

Since 2024

Free plan · Courses and learning · Individuals and families

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A study app for students with spaced repetition flashcards, made from notes and PDFs, and scheduled around your calendar.

Free plan · Courses and learning · Individuals and families

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Sends messages from your scripts, servers or webhooks straight to the Pocket Alert app on your iPhone or Android phone.

Since 2024

Free plan · Uptime and monitoring · Developers

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A free personal URL that emails you when a script, cron job or build calls it, for developers who want simple alerts.

Free · Uptime and monitoring · Developers

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A WooCommerce plugin that lets shops sell subscriptions, repeat deliveries and instalment plans, with dunning and cancellation flows.

Payments and checkout · Online sellers

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A light self-hosted Git server with a web interface that runs as one binary or Docker container on small machines.

Free · Developer tools · Developers

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Lets app and game developers change settings and run A/B tests remotely, without shipping a new build or waiting for store review.

Since 2024

Developer tools · Developers

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Hosted service that receives, logs and retries webhooks, with a CLI for local testing and a typed SDK.

Since 2024

Developer tools · Developers

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Receives incoming email and passes each message to your app as a signed HTTP POST, so there's no need to run a mail server.

Free · Developer tools · Developers

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Turns PDF liability waivers into online forms that customers sign, for businesses that still collect paper waivers.

Free plan · Documents and e-signature

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Budgeting app that links bank accounts, flags bills due before payday and lets couples split costs they choose to share.

Free plan · Money and budgeting · Individuals and families

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Flashcard maker that schedules reviews by spaced repetition, with dictionaries and text to speech for language learners.

Since 2024

Free plan · Courses and learning · Individuals and families

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A form backend for developers that adds front-end validation, autoresponders and spam blocking, with a HIPAA option.

Free trial · Forms and surveys · Health and clinics

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A small headless CMS for writing and publishing blog posts and media, pulled into your site by API.

Free plan · Website builders · Creators and writers

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Gives static website forms a hosted endpoint that stores submissions, filters spam and sends alerts to email, Slack or Discord.

Forms and surveys · Developers

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Flashcard app for iPad and iPhone where students draw, type or add images to cards and review them with spaced repetition.

Since 2024

Courses and learning · Individuals and families

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Flashcard app that uses spaced repetition so learners review hard cards more often, with sync between devices.

Courses and learning · Individuals and families

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Hosted backend that takes in webhooks from Stripe, Shopify and others, stores them and runs your code with queues, cron and retries.

Since 2024

Free plan · Developer tools · Developers

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Spreadsheet that links to databases and files and lets AI write the formulas, Python and charts for you.

Since 2023

Data and spreadsheets

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An API that renders HTML and saved templates into PDFs and screenshots, for developers who need documents from their apps.

Pay as you go · Documents and e-signature · Developers

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An app for learning Japanese with an AI tutor, speaking roleplays, kanji, quizzes and a personal study plan.

Since 2026

Free plan · Courses and learning · Individuals and families

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An email API that developers use to receive mail on their own domain as JSON, route it and reply in the same thread.

Since 2025

Subscription · Transactional email · Developers

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A language app that translates words offline, saves them to your own tagged word list and helps you review them with flashcards.

Since 2025

Courses and learning · Individuals and families

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Fixes the mixed content and insecure content warnings a WordPress site shows after it moves to HTTPS.

Website builders

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An API that gives AI agents their own email inboxes to send and receive mail, with webhooks and scanning for prompt injection.

Since 2026

Free plan · Transactional email · Developers

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An API and MCP server that lets AI agents send contracts and collect two-party signatures by email.

Since 2026

Free plan · Documents and e-signature · Developers

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One MCP server that gives AI agents hundreds of sourced data streams like weather, markets and releases, with full history.

Since 2026

Developer tools · Developers

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Gives you one fixed webhook URL that forwards Stripe and Paddle events to whichever branch deployment you are testing.

Since 2026

Free plan · Developer tools · Developers