schemax

Infer JSON Schema from sample data. Feed it one or more JSON files and get a clean, mergeable schema back.

Install

pip install schemax-cli

Usage

# Infer schema from a single file
schemax infer data.json

# Infer from multiple examples (schemas are merged)
schemax infer example1.json example2.json example3.json

# Infer from a JSON array (each element = sample)
schemax infer users.json

# From stdin
cat data.json | schemax infer -

# With title and compact output
schemax infer data.json --title "User" --compact

# Disable format detection
schemax infer data.json --no-formats

# Different draft version
schemax infer data.json --draft 7

Commands

Format Detection

Automatically detects and annotates string formats:

• date-time — ISO 8601 timestamps
• date — YYYY-MM-DD dates
• time — HH:MM:SS times
• email — Email addresses
• uri — HTTP(S) URLs
• uuid — UUIDs
• ipv4 — IPv4 addresses

Multi-File Merging

When given multiple files (or a JSON array), schemax merges schemas intelligently:

• Object properties from all samples are combined
• required = intersection (only keys present in ALL samples)
• Types are widened (integer + number → number)
• Nullable fields are detected
• Conflicting types produce anyOf

For AI Agents

See SKILL.md for agent-optimized documentation.

License

MIT