JSON to Custom Template — Free Online Converter with Powerful Template Syntax

What Is JSON?

JSON (JavaScript Object Notation) is a lightweight, text-based data-interchange format defined by RFC 8259. It represents structured data as arrays and key-value objects. REST APIs, configuration files, databases, and data pipelines use JSON as their primary exchange format.

Example JSON array:

[
 {"id": 1, "name": "Alice", "email": "[email protected]"},
 {"id": 2, "name": "Bob", "email": "[email protected]"}
]

What Is a Custom Template?

A custom template is a text pattern containing placeholders. The tool replaces each placeholder with data from your JSON and outputs the result. This approach lets you convert the same JSON dataset into any text format — SQL statements, CSV rows, HTML snippets, code files, shell commands, or configuration blocks — without writing scripts.

Why Convert JSON to a Custom Template?

Without this tool, each format conversion requires a custom script. This tool replaces all of them with a single template definition.

Core Features

1. Dual Input Modes

• File Upload: Drag and drop or select a .json file.

• Code Editor: Paste or type JSON directly. Real-time validation shows "Valid JSON" or "Invalid JSON" status.

2. Built-in Template Library

Pre-configured templates organized by category:

3. Custom Template Syntax

4. Three Template Sections

• Header Template: Applied once before all rows (e.g., INSERT INTO table VALUES or a file header).

• Row Template: Applied to every JSON object (the main conversion logic).

• Footer Template: Applied once after all rows (e.g., closing brackets, COMMIT;).

5. Privacy by Design

All processing runs entirely in your browser. No data is uploaded to any server. The tool works offline after the initial page load.

How to Use This JSON to Custom Template Converter?

Step 1: Provide Your JSON Data

• Upload a file: Click "Choose File" and select a .json file, or drag it into the upload area.

• Paste data: Click "Enter Data" to switch to the code editor. Paste your JSON array. The editor validates syntax in real time.

Step 2: Select or Create a Template

Option A — Use a Built-in Template:
Open the "Built-in Template" dropdown and select a template. The Row, Header, and Footer fields populate automatically.

Option B — Write a Custom Template:
Choose "Make your Magic" from the dropdown, then write your own:

• Row Template (required): Define the output pattern for each row using {$1}, {$2}, etc.

• Header Template (optional): Output text before all rows.

• Footer Template (optional): Output text after all rows.

Step 3: Convert

Click Convert. The output appears in the "Output Data" panel.

Step 4: Copy or Download

• Click Copy to Clipboard to paste the result.

• Premium users can click Download File to save the output.

Practical Examples

Example 1: Generate SQL INSERT Statements

JSON Input:

[
 {"id": 1, "name": "Alice", "role": "Engineer"},
 {"id": 2, "name": "Bob", "role": "Designer"}
]

Row Template:

INSERT INTO employees (id, name, role) VALUES ({$1}, '{$2}', '{$3}');

Output:

INSERT INTO employees (id, name, role) VALUES (1, 'Alice', 'Engineer');
INSERT INTO employees (id, name, role) VALUES (2, 'Bob', 'Designer');

Example 2: Generate HTML Select Options

Row Template:

<option value="{$1}">{$2}</option>

Output:

<option value="1">Alice</option>
<option value="2">Bob</option>

Example 3: Batch File Rename

Row Template:

ren "{$1}.txt" "{$2}.txt"

Output:

ren "1.txt" "Alice.txt"
ren "2.txt" "Bob.txt"

Example 4: CSV with Semicolons (Built-in)

Select "CSV with Semi-colons" from the dropdown. The tool generates:

1;Alice;Engineer2;Bob;Designer

Example 5: Add Row Numbers

Row Template:

{NR}. {$2} — {$3}

Output:

1. Alice — Engineer
2. Bob — Designer

Supported JSON Input Formats

• JSON arrays of objects: [{"key": "value"}, ...] — most common

• JSON arrays of arrays: [["val1", "val2"], ...]

• Nested objects: Flattened to dot-notation keys automatically

Frequently Asked Questions （FAQ）

• Does the tool upload my data to a server?

  No. All conversion happens locally in your browser. Your data never leaves your device.

• What does the template syntax {$1} mean?

  {$1} is a placeholder that gets replaced with the value of the first field in each JSON object. {$2} is the second field, and so on. You can also use {$A}, {$B}, etc.

• Can I use JavaScript functions in templates?

  Yes. The syntax {x expression} evaluates any JavaScript expression. For example, {x new Date().toISOString()} inserts the current timestamp.

• What is the difference between Header, Row, and Footer templates?

  
  

  1. Header outputs once before all rows.

  2. Row outputs once per JSON object (repeated for each row).

  3. Footer outputs once after all rows.

  
  

• What built-in templates are available?

  SQL (INSERT, UPDATE), CSV, HTML select options, JIRA tables, PHP arrays, C arrays, LDIF, URL query strings, batch rename commands, and file creation scripts. Select any from the dropdown to auto-populate the template fields.

• Can I convert JSON to SQL online?

  Yes. Select "SQL: Insert example" or "SQL: Update example" from the built-in template dropdown, or write your own SQL template using the syntax INSERT INTO table (col1, col2) VALUES ('{$1}', '{$2}');.

• Is there a file size limit?

  The tool processes data entirely in your browser. Files up to 10 MB typically convert without issues on modern hardware.

• Can I use this on mobile?

  Yes. The tool is responsive and works on smartphones and tablets.