Slate Viewer guide
Open JSONL and NDJSON files on Mac
AI tools, exports, and logs often write one result after another into a line-delimited JSON file. Slate Viewer opens that local file in a reader-first view, while keeping the exact source close at hand.
Quick answer
JSONL and NDJSON are two names for the same line-delimited JSON structure. Slate Viewer 1.0 opens .jsonl and .ndjson files locally on macOS 26.0 or later: Preview helps you read the sequence of values, while Raw keeps every original line, delimiter, and escape sequence available for exact checking.
JSONL vs NDJSON: the same line-delimited structure
JSONL and NDJSON are common names for the same pattern: each non-empty line is a standalone valid JSON value. A line is often an object, but it can also be an array, string, number, boolean, or null. That makes the format useful for records that arrive or are written one at a time.
Why these files are different from one JSON document
A regular JSON file usually contains one top-level value. A JSONL or NDJSON file contains a sequence of independent values separated by line breaks. That structure is common in AI result streams, data exports, and logs, where reading the records and checking the original line are both important.
A local reading workflow
- Open the file locally. Use Finder Open With or open it from Slate Viewer.
- Start with Preview. Orient yourself before working through the source line by line.
- Switch to Raw when details matter. Check the exact line, value, delimiter, or escape sequence Slate Viewer opened.
- Keep corrections focused. Use Light Edit for a small supported local text change, not as a replacement for a full data editor.
A reader, not a JSONL repair tool
Slate Viewer is useful when you need to review AI batch output, an export, or a log without pasting it into a website. It keeps the readable representation and exact source together, but it is not a schema validator, converter, database client, or large-dataset processing tool. Use a dedicated data tool when validation, transformation, or bulk editing is the actual task.
Local by default
Slate Viewer opens JSONL and NDJSON files on your Mac. It does not upload document text, file paths, JSON fields, or clipboard contents to Slate Viewer servers by default. It is a file reader, not a cloud workspace or an AI assistant.
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Slate Viewer for Mac