A search engine aggregator
Metasearch is a meta-search engine in the form of an extension. It aggregates results from online search engines, that can either be general (such as DuckDuckGo) or domain-specific (such as IMDb).
All of these results are fetched through the browser (as separate tabs opened by the extension), so there is no centralized "Metasearch" service. This means that the user is no more anonymous than if you were directly accessing these websites, but it also makes it very easy to access login-bound search engines such as library websites.
The Metasearch extension looks as much as an online search engine as possible, and is installed as one in the browser, so it can be set as the default search engine.
Metasearch intends to be easy to use, private, and versatile. While general search engines, such as Google, are good at answering all kinds of searches, a large part of the time, the answers come from a small selection of large websites, such as Wikipedia, or StackOverflow. These websites have their own search, but it would be quite cumbersome to search each one manually. Metasearch aims to facilitate this process, and answer a large percentage of queries with domain-specific search engines, while deferring to general search engines in the rest.
Metasearch ought to be as fast as the fastest engine it queries (at least for displaying initial results). As such, it is faster than other search aggregators, such as Searx, which by design have to wait for the slowest result. Furthermore, Metasearch is intended for personal use, and thus is packaged as a browser extension, so the user does not need to manage their own server.
In order to improve user experience, each engine is associated with a set of aliases and keywords (configured through the options page). Aliases (such as ddg for DuckDuckGo) enable the associated engines and are removed from the search query. If the search query contains any aliases, only the engines that contain at least one of these aliases are queried. Different engines may share aliases (both Merriam-Webster and Wiktionary share the "define" alias), and the same engine may have multiple aliases (IMDb has the aliases "movie", "tv", and "imdb"). Keywords (such as "python" for StackOverflow) enable the associated engines but are not removed from the search query. The star (*) keyword matches all queries (enabled by default for DuckDuckGo and Wikipedia). If an engine's keywords exist in the query, but its alias doesn't it will only be queried if the query does not contain any aliases.
