25 KB JS sample
A JS file of exactly 25,600 bytes. It is a valid JavaScript source file file, generated by this site. Compare its checksum and test it with the parser used by your application. Use it wherever you need a 25 KB sample, test or dummy JS file.
Download
sample-js-25kb.js
25 KB25,600 bytes
Download 25 KB JSCreated in your browser in a few seconds, then checked against the SHA-256 checksum. The file is not uploaded anywhere. No sign-up.
- Type
- text/javascript
- SHA-256
59ca7a6c44bb4ed5b85ef40ba5ab617e9f3cc882f099b1ed3d0d7438a164dc1b- Delivery
- Created in your browser from static generator assets (how it works).
What is in this file
Strict-mode JavaScript that declares an array of 206 record objects and two helper functions, and runs nothing when loaded. Comment lines at the end bring the file to the exact size.
| Records | 206 |
|---|---|
| Functions | 2 (totalBalance, findById) |
| Module format | Script, with a CommonJS export when available |
| Dependencies | None |
| Encoding | UTF-8 (ASCII characters only) |
How the file begins
The opening lines of sample-js-25kb.js, exactly as they appear in the file.
00000000 2f 2f 20 53 61 6d 70 6c 65 54 65 73 74 46 69 6c |// SampleTestFil|
00000010 65 73 20 73 61 6d 70 6c 65 20 4a 61 76 61 53 63 |es sample JavaSc|
00000020 72 69 70 74 20 66 69 6c 65 20 28 32 35 20 4b 42 |ript file (25 KB|
00000030 29 0a 2f 2f 20 50 6c 61 69 6e 20 45 43 4d 41 53 |).// Plain ECMAS|Preview
Shows the file contents.
Where 25 KB matters
A 25,600-byte file: the size of a small web image or a short document. These are the default limits a file of this size is useful for testing:
| System | Limit | Note |
|---|---|---|
| TCP initial congestion window | About 14.6 KB (10 segments) | 25 KB needs at least two flights of packets on a new connection. |
| Base64 encoding | Adds 33 percent | A 25 KB file becomes about 34 KB inside JSON or an email. |
Use this file for
- Checking thumbnail and icon handling
- Testing static asset delivery and caching
- Testing bundlers and minifiers with large inputs
Testing notes for JS
- The old types application/javascript and application/x-javascript are obsolete; text/javascript is the registered type.
- Never execute an uploaded script. Treat .js uploads as text to be stored or analysed.
Technical details
| File name | sample-js-25kb.js |
|---|---|
| Format | JS (JavaScript source file) |
| Extension | .js |
| MIME type | text/javascript |
| Size | 25,600 bytes (25 KB) |
| Kind | Text |
| SHA-256 | 59ca7a6c44bb4ed5b85ef40ba5ab617e9f3cc882f099b1ed3d0d7438a164dc1b |
| Created | 2026-10-23 |
| Validation | See the listed size and SHA-256. Small downloads are checked in the browser; verify streamed downloads manually. A hash match does not prove parser compatibility. |
| Preview | Available on this page |
| Source | Generated in your browser by this site's generator; not copied from elsewhere |
| Licence | Free to use, modify and redistribute (terms) |
| Category | Code |
Check the stated structure and checksum against your application requirements. As with any download, scan the file with your own security tools before opening it. How files are made and checked
Verify your copy
This file is created in your browser, so it has no direct URL for curl or wget. The generator is designed to produce reproducible bytes. After saving, compare the checksum with the SHA-256 value above.
sha256sum sample-js-25kb.js # Linux
shasum -a 256 sample-js-25kb.js # macOSOn Windows, run Get-FileHash sample-js-25kb.js -Algorithm SHA256 in PowerShell. For scripts and pipelines, save the file once and keep your own copy.
Related files
Questions about this file
- Is this file exactly 25 KB?
- Yes. It is 25,600 bytes, which is 25 KB in the binary units that operating systems and server limits use (1 KB = 1,024 bytes).
- What is inside the 25 KB JS file?
- Strict-mode JavaScript that declares an array of 206 record objects and two helper functions, and runs nothing when loaded. Comment lines at the end bring the file to the exact size.
- Does the sample script do anything when loaded?
- No. It defines an array and two functions and has no side effects.