Does Insert at Index upload my file or text to Tool-You servers?

No. Insert at Index runs in this browser tab. Files stay on the device. Limit note: 0-based index in range. Empty fails.

Should I use Delete at Index instead of Insert at Index?

Use Insert at Index when you need Insert text at a character index. Use Delete at Index when you need Delete characters from an index. They share a category (Developer) but not the same job.

Insert at Index

Insert text at a character index.

Inserts a string at a 0-based index. Unlike Delete at Index this inserts. Index out of range fails. Empty base fails.

What Insert at Index does

Inserts a string at a 0-based index. Unlike Delete at Index this inserts. Index out of range fails. Empty base fails.

Practical limit for Insert at Index: 0-based index in range. Empty fails. That is why output can differ from heavy desktop Developer software. Read the tool-specific note again: Inserts a string at a 0-based index. Unlike Delete at Index this inserts. Index out of range fails. Empty base fails.

How to use Insert at Index

Keep this tab on Insert at Index (/developer/insert-at-index). Pasting into the wrong Developer tool (for example Delete at Index) changes the job.
Paste or type the input Insert at Index expects. Path hint: developer · insert at index. Insert text at a character index.
Apply the Insert at Index action only. Slice Text Range is a different transform (Slice text by start/end indexes.). Inserts a string at a 0-based index. Unlike Delete at Index this inserts. Index out of range fails. Empty base fails.
Copy the output of Insert at Index if you need it elsewhere. Size/complexity still follows: 0-based index in range. Empty fails.
If the text job is actually Delete characters from an index., leave Insert at Index and open Delete at Index.

When not to use Insert at Index

Skip Insert at Index when a neighbor tool matches better — start with Delete at Index or Slice Text Range — or when the description already warns the job will fail. In the tool’s own words: Inserts a string at a 0-based index. Unlike Delete at Index this inserts. Index out of range fails. Empty base fails.

Questions about Insert at Index

What does Insert at Index do that other Developer pages on this site do not?: Inserts a string at a 0-based index. Unlike Delete at Index this inserts. Index out of range fails. Empty base fails. Short version: Insert text at a character index.
Does Insert at Index upload my file or text to Tool-You servers?: No. Insert at Index runs in this browser tab. Files stay on the device. Limit note: 0-based index in range. Empty fails.
Should I use Delete at Index instead of Insert at Index?: Use Insert at Index when you need Insert text at a character index. Use Delete at Index when you need Delete characters from an index. They share a category (Developer) but not the same job.
What are the limits of Insert at Index?: 0-based index in range. Empty fails. Also: Inserts a string at a 0-based index. Unlike Delete at Index this inserts. Index out of range fails. Empty base fails.