# Overview At the heart of the timing layer are **devices**, **sessions**, and **passings**: * A **device** is any hardware or software capable of detecting a competitor at a specific point—typically by reading a bib number or chip and assigning it a timestamp. * A **session** is created by a device to group a set of passings during a specific timing operation. * A **passing** represents a single recorded event: a competitor identifier and a timestamp generated by a device. The typical flow is simple:\ a device authenticates using an API key → creates a session → sends passings to that session. On top of this ingestion layer, the API now exposes an **event and participant data model**, enabling deeper integrations: * An **event** represents a race or competition managed within the RUFUS ecosystem. * **Participants** are the competitors registered in an event, including their identifiers (bib, chip, etc.) and associated data. This allows external systems not only to send timing data, but also to **consume and manage event-related information**, such as listing events, retrieving participants, or creating new participant records (depending on API key permissions). Before interacting with any of these resources, access must be granted through an **API key**, which defines the level of permissions (read, write, or both) available to your integration. Together, these components provide a complete workflow—from capturing raw timing data in the field to integrating structured event information in the cloud. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://help.runonrufus.com/public-api/getting-started/overview.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.