Compact Data

Choose text input when whitespace is part of the baseline, or parsed JSON when the object is already in memory.

Compact text

Python

from axm_smelt import smelt

data = '{\n  "name": "Alice",\n  "age": 30\n}'
report = smelt(data)
print(report.compacted)
print(report.original_tokens, report.compacted_tokens)
print(f"{report.savings_pct:.2f}% saved")
assert report.compacted_tokens <= report.original_tokens

The default safe preset still changes representation. Review format-specific limits for XML, YAML, and Markdown before using the result in a parser or renderer.

Compact an existing object

Python

from axm_smelt import smelt

payload = {"name": "Alice", "notes": None}
report = smelt(parsed=payload, strategies=["minify", "drop_nulls"])
assert payload["notes"] is None
print(report.original)   # Compact JSON baseline, before the strategies
print(report.compacted)

A nonempty strategy list overrides preset; an empty list falls back to the preset/default. Only accepted transforms appear in strategies_applied. A selection is not a guarantee that each strategy will be applied.

Save only the compacted text

This example writes a separate output file in the current directory:

Python

from pathlib import Path
from axm_smelt import smelt

source = Path("payload.json").read_text(encoding="utf-8")
report = smelt(source)
Path("payload.compacted.txt").write_text(report.compacted, encoding="utf-8")

For a JSON consumer, validate the parsed result against the source before writing it. moderate and aggressive can change shape, values, and syntax.

Use the CLI

In an activated environment containing the package (or with uv run):

Bash

printf '{"name": "Alice", "notes": null}\n' | axm smelt
axm smelt --input-path ./payload.json --preset moderate --json-output

Plain stdout includes a header. JSON output contains the compacted string and metrics; extract compacted if you need just the payload. See CLI argument encoding and all report fields.