---
title: Captures
---

Captures let you describe Change Data Capture (CDC) pipelines that turn external data changes into Chronicle events.

## Overview

A capture definition describes:

- **Source**: where data comes from (`api`, `webhook`, `message`)
- **Identity key**: the property used to detect changes per entity
- **Mapping**: optional transformations before append logic
- **Append rules**: which event to append and when to append it
- **Scopes**: root, nested objects, and child collections

Chronicle supports three authoring approaches. Only the first is language-neutral — the other two are .NET client features, documented alongside the rest of the .NET client:

- **Capture Declaration Language (CDL)** for text-based definitions
- **Declarative API** (.NET) for fluent definitions in code
- **Model-bound API** (.NET) for attribute-based definitions

## Topics

| Topic | Description |
| ----- | ----------- |
| [Capture Declaration Language](/chronicle/captures/capture-declaration-language/) | CDL syntax, semantics, and formal language specification |
| [Declarative Captures](/chronicle/clients/dotnet/captures/declarative/) | .NET client fluent API (`ICapturer` + `ICaptureBuilder`) |
| [Model-Bound Captures](/chronicle/clients/dotnet/captures/model-bound/) | .NET client attribute-based capture declarations |