# How to Get JSON Output from IPATool: A Complete Guide to Structured Logging

> Learn how to get JSON output from IPATool using the --format json flag. This guide provides a complete solution for structured logging in your projects.

- Repository: [Majd/ipatool](https://github.com/majd/ipatool)
- Tags: how-to-guide
- Published: 2026-09-01

---

**Use the global `--format json` flag with any IPATool command to emit structured JSON output to stdout instead of human-readable text.**

IPATool is a command-line utility for interacting with the App Store ecosystem. When you need to script downloads, automate searches, or integrate with data pipelines, configuring **JSON output from IPATool** provides the structured data necessary for programmatic processing.

## How the `--format` Flag Works

The `--format` flag is a persistent global argument registered on the root command. When you pass `--format json`, the CLI reconfigures its internal logging system to output structured data using **zerolog**, a high-performance structured logging library.

In [[`cmd/output_format.go`](https://github.com/majd/ipatool/blob/main/cmd/output_format.go)](https://github.com/majd/ipatool/blob/main/cmd/output_format.go), the codebase defines the `OutputFormat` enumeration and the `OutputFormatJSON` constant that represents the JSON mode. The flag binding occurs in [[`cmd/root.go`](https://github.com/majd/ipatool/blob/main/cmd/root.go)](https://github.com/majd/ipatool/blob/main/cmd/root.go), which maps the string values `"json"` and `"text"` to their respective internal constants.

When JSON mode is selected, the initialization logic in [[`cmd/common.go`](https://github.com/majd/ipatool/blob/main/cmd/common.go)](https://github.com/majd/ipatool/blob/main/cmd/common.go) creates a logger using `zerolog.SyncWriter(os.Stdout)`. This writer ensures thread-safe, streaming JSON output where each log entry or command result becomes a self-contained JSON object separated by newlines.

## Practical Examples for JSON Output

You can append `--format json` to any IPATool operation. These patterns demonstrate common automation workflows:

```bash

# Download an app and capture metadata as JSON

ipatool download com.example.app --format json

# Search the App Store and extract specific fields with jq

ipatool search "photo editor" --format json | jq '.apps[] | {name, bundleID}'

# List all versions of an app for version pinning

ipatool list-versions com.example.app --format json > versions.json

# Combine with verbose mode for detailed request metadata

ipatool download com.example.app --format json --verbose

```

The output integrates seamlessly with standard Unix pipes, allowing you to chain IPATool with `jq`, `grep`, or custom Python scripts for further processing.

## Source Code Implementation Details

According to the `majd/ipatool` source code, the JSON output capability spans three architectural layers:

- **[[`cmd/output_format.go`](https://github.com/majd/ipatool/blob/main/cmd/output_format.go)](https://github.com/majd/ipatool/blob/main/cmd/output_format.go)**: Defines the `OutputFormat` type and the `OutputFormatJSON` constant used throughout the application.
- **[[`cmd/root.go`](https://github.com/majd/ipatool/blob/main/cmd/root.go)](https://github.com/majd/ipatool/blob/main/cmd/root.go)**: Registers the persistent `--format` flag on the cobra root command, validating user input against allowed values (`"json"`, `"text"`).
- **[[`cmd/common.go`](https://github.com/majd/ipatool/blob/main/cmd/common.go)](https://github.com/majd/ipatool/blob/main/cmd/common.go)**: Contains the runtime initialization that switches between human-readable formatters and `zerolog.SyncWriter(os.Stdout)` when `OutputFormatJSON` is active.

## Summary

- **Use `--format json`** as a global flag on any IPATool command to enable structured output.
- The JSON mode utilizes **zerolog** via `zerolog.SyncWriter(os.Stdout)` for high-performance, thread-safe streaming.
- Key source files include [`cmd/output_format.go`](https://github.com/majd/ipatool/blob/main/cmd/output_format.go), [`cmd/root.go`](https://github.com/majd/ipatool/blob/main/cmd/root.go), and [`cmd/common.go`](https://github.com/majd/ipatool/blob/main/cmd/common.go).
- JSON output is newline-delimited and designed for integration with `jq`, Python's `json` module, and CI/CD pipelines.

## Frequently Asked Questions

### What is the default output format for IPATool?

By default, IPATool uses a human-readable **text** format. If you omit the `--format` flag, the CLI renders output as formatted plain text with color coding where supported, corresponding to the `OutputFormatText` constant defined in [`cmd/output_format.go`](https://github.com/majd/ipatool/blob/main/cmd/output_format.go).

### Can I use JSON output with every IPATool command?

Yes. The `--format` flag is defined as a persistent flag on the root command in [`cmd/root.go`](https://github.com/majd/ipatool/blob/main/cmd/root.go), making it available to all subcommands including `download`, `search`, `list-versions`, and `purchase` without exception.

### How does IPATool generate the JSON structure?

IPATool uses the **zerolog** library to serialize log entries and command results. In [`cmd/common.go`](https://github.com/majd/ipatool/blob/main/cmd/common.go), when `OutputFormatJSON` is detected during initialization, the logger is configured with `zerolog.SyncWriter(os.Stdout)`, which outputs compact, newline-delimited JSON objects optimized for streaming parsers.

### Is the JSON output pretty-printed or minified?

The output is **compact (minified)** JSON. Zerolog's default configuration in [`cmd/common.go`](https://github.com/majd/ipatool/blob/main/cmd/common.go) emits newline-delimited JSON without extra whitespace or indentation. For human-readable formatting, pipe the output through `jq .` or similar JSON formatting tools.