Visual JSON Diff & Data Comparison

Fine-Tune Your JSON Responses and Algorithms

Comparing the output of different algorithm versions is crucial for development. Slicelytics lets you easily diff two JSON or CSV datasets to pinpoint the exact impact of your changes. It's an indispensable JSON diff tool for regression testing and verifying the behavior of your APIs and data transformations.

Debug and Monitor Data with Precision

Track down bugs by comparing a known-good dataset with a problematic one. Understand why your data looks different for various users or scenarios. Monitor data modifications over time to ensure data quality and detect unexpected alterations before they become a problem.

All the Power of Explore, in a Diff

The Compare view inherits all the powerful features of the Explore view. All processing, including decompression of Gzip and Zstandard files, happens in your browser, so your data remains private. Our advanced filtering, keyboard shortcuts, and automatic schema inference are also at your disposal to make comparisons as efficient as possible.

Narrow the diff down to the properties you care about, with autocomplete for nested property names as you type and every active filter shown as a chip you can remove in one click.

Diff Large Datasets, Batch by Batch

Both sides of a diff can be large. NDJSON files are streamed into your browser's IndexedDB in the background, on either side, with a progress bar for each, so you can compare two files of several gigabytes without running out of memory. Files in every format are shown 100 items at a time: "Load more" in either pane loads the next batch of both datasets, so matching items stay side by side.

The dataset you compare with is remembered, too. Come back later and both datasets are restored, however large, so you can pick up the comparison where you left it.

Share Your Diffs, Not Your Data

Share your findings with your team. Click Share to copy one link that carries both datasets with only the items and properties you kept, so your colleague sees the same diff you do. The data is compressed into the part of the link after #, which browsers never send to a server, so it's never stored by us. Browsers limit how long a link can be (about 2 MB in Chrome), so sharing suits small and medium datasets.

Let Your AI Agent Open the Diff

Comparing two runs, two API responses, or the output of two algorithm versions with an AI coding agent such as Claude Code? Ask it to "compare before.json and after.json in Slicelytics". Following slicelytics.com/llms.txt, the agent builds a Compare link that carries both files, unchanged. The data travels in the part of the link after #, so it stays in your browser. For larger files or a new file on every run, the agent can write the runs into a watched folder instead.

How the JSON Diff Tool Works

Using Slicelytics to diff your JSON, CSV, or NDJSON datasets is straightforward:

1. Step 1: Drop Your Baseline Data: Select or drag-and-drop your original standard dataset (the "before" state).
2. Step 2: Drop Your Modified Data: Upload the new, updated dataset (the "after" state). Both datasets are remembered for your next visit.
3. Step 3: Instantly Review the Diff: Slicelytics immediately highlights structural shifts, missing keys, and value alterations side-by-side.
4. Step 4: Zoom in on the Diffs that Matter to You: Use the available filtering options to compare only the properties you're interested in.

Built For Modern Data Engineering Workflows

Our compare tool is optimized specifically for technical professionals working directly with raw datasets:

• For Backend Developers: Quickly catch API regressions by diffing API responses between your staging and production environments.
• For Data Engineers: Validate ETL data pipeline outputs by comparing structural changes in massive NDJSON log outputs, streamed on both sides of the diff.
• For QA Teams: Rapidly verify dataset integrity against a known-good baseline CSV or TOON file locally.
• For Developers Working with AI Agents: Have your agent open the diff between two runs in Slicelytics, then filter it yourself.

Supported Formats and Encodings

We handle the complex parsing operations so you can focus entirely on comparing the generated diffs. Slicelytics effortlessly supports the following file formats:

• .json
• .ndjson / .jsonl (Newline Delimited JSON / JSON Lines)
• .csv
• .toon

Are your datasets safely compressed in storage? There is no need to manually unpack them first. The diff tool provides fully client-side decompression for datasets stored as .gz (Gzip) and .zst (Zstandard) straight in your browser window.