Latest Update
v0.0.5.2 is now available

JSSON: Universal Config Format
Supercharged

JSSON isn’t just another format — it’s a meta-format. Write your logic once, and let it spit out JSON, YAML, TOML, or fully typed TypeScript. No repetition. No boilerplate. No crying.

Start Coding Documentation
terminal CLI
jsson --version

Why JSSON?

Stop repeating yourself in JSON. Upgrade to a language designed for modern application configuration.

Universal Multi-Format Output

Write once, export everywhere. Convert JSSON into JSON, YAML, TOML, or TypeScript — your entire config ecosystem from a single source of truth.

Declare Variables

Declare variables once and reuse them throughout your config. No more copy-pasting values.

Reusable Templates

Define structured data models once and instantiate them with spreadsheet-style rows. Zero duplication, maximum clarity.

Advanced Maps

Transform values declaratively with map(). Generate derived fields, dynamic objects and multidimensional data pipelines with nested mappings.

Powerful Ranges

Generate massive datasets with 1..10000, nested ranges, and range-driven maps. Ideal for geodata, schedules, grids and simulations.

Expressions & Logic

Full math, comparisons, modulo, ternaries and computed properties right inside the DSL — no scripting needed.

Nested Arrays & Complex Structures

Naturally express deep arrays, nested maps, multi-level expansions and matrix-like outputs with clean declarative syntax.

Includes & Composition

Break large configs into logical parts and merge them with include. Supports keep, overwrite, and strict error modes.

Native Types, No Boilerplate

Strings, ints, floats, booleans, objects and arrays — without JSON’s quoting hell. Clean syntax built for humans.

High-Scale Data Generation

Create thousands or millions of records with a few lines. Perfect for seeds, mocks, simulations, grids, and AI datasets.

Inline-Safe & LLM-Friendly

Minifiable, stable under compression, and easy for LLMs to parse. JSSON wasn’t built for AI, but AI absolutely loves it.

New in v0.0.5

Data Generation Powerhouse

JSSON v0.0.5 introduces nested maps, nested arrays, and universal ranges. Turn complex data generation into simple, readable code.

Nested Maps

Matrix Generation

25 numbers in 1 line

Generate 2D matrices using nested map transformations

input.jsson
// Multiplication table 5x5
rows := 5
cols := 5
 
table = (1..rows map (row) = (
1..cols map (col) = row * col
))
output
1
2
3
4
5
2
4
6
8
10
3
6
9
12
15
4
8
12
16
20
5
10
15
20
25

Product Variants

E-commerce Power

6 variants automatically

Generate all size/color combinations effortlessly

input.jsson
products = (["S", "M", "L"] map (size) = (
["Red", "Blue"] map (color) = {
sku = size + "-" + color
price = 29.99
}
))
output
SKU: S-Red
Size S
$29.99
SKU: S-Blue
Size S
$29.99
SKU: M-Red
Size M
$29.99
SKU: M-Blue
Size M
$29.99
SKU: L-Red
Size L
$29.99
SKU: L-Blue
Size L
$29.99

Large-Scale Generation

Massive Datasets

1,000 records instantly

Generate thousands of records with patterns

input.jsson
totalUsers := 1000
users = (0..(totalUsers - 1) map (id) = {
id = id
username = "user_" + id
tier = id < 100 ? "bronze" : "silver"
})
output
1,000
records generated
100 bronze
900 silver

Ready to supercharge your data generation?

Try It in Playground

Write Logic,
Get JSON, YAML, TOML, TypeScript.

JSSON brings the power of a real programming language to your configuration files. No more copy-pasting or manual error-prone editing.

Native variables & constants
Arithmetic & Conditional Logic
Templates & Maps for complex arrays
Smart Ranges with steps
Modular configuration (include)
input.jssonJSSON
// Simple configuration
api {
url = "https://api.example.com"
timeout = 5000
retries = 3
headers {
content_type = "application/json"
auth_token = "bearer-token-123"
}
}
output.json
{
"api": {
"url": "https://api.example.com",
"timeout": 5000,
"retries": 3,
"headers": {
"content_type": "application/json",
"auth_token": "bearer-token-123"
}
}
}

Frequently Asked Questions