Manage Columns in JSON Files Online

Drop or select specific columns from JSON files directly in your browser. No upload required.

How to manage Columns in JSON files

Drop your file onto the upload area. Every column is listed as a chip with its detected type, and all are selected to start with.
Click a chip to deselect a column you want to drop. It turns grey with a line through it. Click again to bring it back.
Use Deselect all and then click the few columns you need when you only want to keep a handful.
Click Apply to preview the result, then Download to save it in the same format you uploaded.

Your file is processed locally in your browser and is never uploaded. The free limit is 50 MB per file; larger files work if your device has the memory for them.

Worked example

An HR analyst needs to send a headcount list to a facilities team, without salary or national ID numbers.

Input (JSON)

[
  {
    "emp_id": 2041,
    "name": "Maria Keane",
    "dept": "Finance",
    "salary": 68000,
    "national_id": "KX 44 91 02 C"
  },
  {
    "emp_id": 2042,
    "name": "Dev Patel",
    "dept": "Operations",
    "salary": 54500,
    "national_id": "LM 20 17 88 A"
  },
  {
    "emp_id": 2043,
    "name": "Sofia Brandt",
    "dept": "Finance",
    "salary": 71200,
    "national_id": "PR 63 05 19 D"
  }
]

Settings

Deselected: salary, national_id
Kept: emp_id, name, dept

Result

emp_id	name	dept
2041	Maria Keane	Finance
2042	Dev Patel	Operations
2043	Sofia Brandt	Finance

The two sensitive columns are removed entirely, not blanked, so they are absent from the downloaded file. The three kept columns stay in their original left-to-right order with their original types. Every row is kept, and no values change.

Working with JSON files

Each top-level key in the JSON array is listed as a column. Deselecting one removes that key from every object in the output. Nested objects appear as a single STRUCT column, so an address object is kept or dropped as a whole. To remove only address.phone, flatten the file first and drop that flattened column. Arrays of values are one column each as well. The chip for each key shows its detected type, such as BIGINT, VARCHAR or a STRUCT, so nested keys are easy to recognise.

This is a quick way to strip internal fields, such as _id, created_by or debug flags, from an API response before sharing it. The result is a pretty-printed JSON array. Kept keys follow the column order shown in the list, and a kept key that was missing from an object in the source is written as null. Removing large unused fields can shrink a JSON file a lot, since every object repeats every key name. Values in kept keys are unchanged.

Frequently Asked Questions

Can I remove a key from every object in a JSON array?

Yes. Deselect that key's chip and Apply. The key is removed from every object in the downloaded file.

How do I drop a nested JSON key such as user.email?

Nested objects are listed as one column. Flatten the JSON first so user.email becomes its own column, then deselect it.

Can I reorder columns with this tool?

No. Kept columns stay in their original left-to-right order. To change the order, use the SQL Query tool and list the columns in the order you want.

Does selecting columns change any values or types?

No. Kept columns are copied exactly, with the same types. Only the dropped columns are removed.

Can I drop every column?

No. At least one column must stay selected, and Apply is disabled until one is.

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