Prefix Index

What is Prefix Index and what is it for?

Prefix Index is a Rust code library that a Holochain app developer adds to their app's own code to make a collection of strings searchable by their first letters. It exists so that apps can offer type-ahead or autocomplete-style searching without each app writing and validating that lookup structure itself.

The project is maintained in the holochain-open-dev organisation, and its repository dates to 2023. It is a small piece of infrastructure rather than something a person uses directly: a component that other Holochain apps include in their own code.

An app adds strings to a named index, and the library creates and validates the links that let those strings be found again by their opening letters. The caller supplies the strings and decides how many results a search should return.

In the documented example an app indexes words such as superdupercool and supercomputing, then searches for "sup". Every indexed word starting with those letters comes back, ordered by similarity and then alphabetically, and the caller sets the result limit; letter case is ignored when indexing but kept in what is returned. The repository README walks through that example and the setup steps.

From 2 public sources, checked 23 September 2026.