Question: I'm looking for a way to add a universal search function to my web app without building it from scratch.

If you want to add a universal search feature to your web app without having to start from scratch, Cmdk is a good option. It lets you easily add a universal search and command widget to your web app with a keyboard-first interface and customizable keyboard shortcuts. It supports major browsers, offers analytics to measure usage, and has a variety of pricing tiers, including a free basic tier.

Another good option is HelpBar, which is geared for SaaS apps. It centralizes help information into a single interface, offering universal search, AI-powered answers and navigation. HelpBar is highly customizable, easy to deploy, and works on all modern browsers, so it's well suited to improving self-serve UX in SaaS environments.

If you need a powerful, open-source search engine, Meilisearch is worth a look. It offers fast, relevant results with search-as-you-type and supports a variety of integrations, including filtering and language detection. Meilisearch offers flexible pricing and good security options, so it's a good choice for sites and apps that need high availability and high performance.

Last, Vespa is a unified search engine and vector database that supports both vector search and lexical search. It's good for building search applications at scale with machine-learned models. Vespa supports a wide variety of data types and offers free usage to get started, so it's a good option for developers who want to add AI-powered search abilities to their apps.