Show HN: Jsonl Viewer – Desktop app for 10M+ rows with nested flattening

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I built this after struggling with Excel/Pandas for large JSONL log files from
IoT devices. The data had deeply nested objects and millions of rows.

The key insight was using simdjson’s on-demand API with parallel chunk parsing,
then flattening nested objects into dot notation (data.device.serial) so you
can filter/sort on nested fields.

Example JSON:
{“user”: {“profile”: {“email”: “test@example.com”}}}

Automatically becomes filterable columns:
– user.profile.email
– user.profile.age

Tech stack: C++, ImGui for UI, simdjson for parsing, HelloImGui for cross-platform.
Uses all CPU cores. Tested with 5GB files (10M records) – loads in ~2 seconds on M2 Mac.

Available for Mac & Windows:
– Mac: https://iotdatasystems.gumroad.com/l/jsonlviewerpro_mac
– Windows: https://iotdatasystems.gumroad.com/l/jsonlviewerpro_win

Launch discount: 50% off with code HN50 (next 48 hours)


Comments URL: https://news.ycombinator.com/item?id=45899724

Points: 1

# Comments: 0

Source: iotdatasystems.gumroad.com

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