Zapier is not available as a self-hosted solution but there are plenty of alternatives for power users and business that want to host a solution on-premise. The most popular Self-Hosted alternative is 
Huginn, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 50 alternatives to Zapier and 12 are available as a self-hosted solution so hopefully you can find a suitable replacement. Other interesting Self-Hosted alternatives to Zapier are 
n8n.io (Free, Open Source), Trigger Happy (Free, Open Source), 
Syndesis (Free, Open Source) and 
elastic.io (Paid).
Zapier enables you to automate tasks between other online services (services like Salesforce, Basecamp, Gmail, and 249 more). If you're looking for more info about Zapier like screenshots, reviews and comments you should visit our info page about it. Below you find the best alternatives.
Huginn is a system for building agents that perform automated tasks for you online. They can read the web, watch for events, and take actions on your behalf. Huginn's Agents create and consume events, propagating them along a directed graph. Think of it as a hackable version of IFTTT or Zapier on your own server. You always know who has your data. You do.
n8n is a free Node-based source-available Workflow Automation Tool. It can be self-hosted, easily extended, and so also used with internal tools.
"Trigger Happy" is a tool that permits to take the control of your data with this opensource clone of IFTTT, a bridge between your internet services that make them speak to each other. Thus, instead of giving your credential to company that provide this kind of service, you own them and keep them with you.
A flexible, customizable, open source platform that provides core integration capabilities as a service.
elastic.io is an Integration Platform as a Service (iPaaS) that allows developers and IT organizations to build, host and maintain integration components as well as integrate disparate SaaS and on-premise solutions like Salesforce or Microsoft Dynamics NAV. The elastic.io Java and Node.js SDKs as well as a number of pre-built open-sourced connector templates make creation of new integration components a breeze.
Beehive is an event and agent system, which allows you to create your own agents that perform automated tasks triggered by events and filters. It is modular, flexible and really easy to extend for anyone. It has modules (we call them Hives), so it can interface with, talk to, or retrieve information from Twitter, Tumblr, Email, IRC, Jabber, RSS, Jenkins, Hue - to name just a few.
Project Flogo is an ultra-light, Go-based open source ecosystem for building event-driven apps. Event-driven, you say? Yup, the notion of triggers and actions are leveraged to process incoming events. An action, a common interface, exposes key capabilities such as application integration, stream processing, etc.
If you use Slack, Skype, Telegram in different teams at the same time, you can feel gloomy, because there is no integration between these services. It looks impossible to connect messages from a slack channel to skype chat. Konektor allows Slack teams and Skype teams to interact easily, without boring copy-past between messengers.
CloudRail API Integration Solution: Save Weeks of Development Time. Unified APIs: Tired of learning different APIs and dealing with bad API documentation? CloudRail gives you a unified API for multiple Web-APIs. So, for instance, the function upload() works exactly the same for Dropbox as it does for Google Drive. Easily integrate whole categories of providers, e.g. Social Log-Ins, or change a provider with a single line of code.
