Does NowConverter upload the file?
No. The selected file is read by JavaScript in your browser. Some format parsers can download their code from a public CDN, but the file bytes are not sent to NowConverter.
Universal File Inspector
Enable JavaScript to inspect files locally.
About this tool
What exactly is inside this file?
Universal File Inspector examines a file's signature bytes instead of trusting only its filename. It can calculate cryptographic fingerprints, compare the extension with the detected format, inspect supported metadata and internal structures, flag common privacy clues, and show a raw header preview. Reports can be copied or downloaded as TXT, PDF or JSON.
What can it inspect?
The current release includes detailed support for common images, PDF files, ZIP and ZIP-based Office documents, audio/media containers, text and JSON/XML files, TrueType/OpenType fonts, Windows PE and ELF binaries, SQLite databases and several other recognizable formats. Unsupported formats still receive basic identity, hash, entropy and raw-header analysis.
Important safety note
This is a structural and metadata inspector, not an antivirus scanner. A file with no warnings is not automatically safe, and a warning does not automatically mean a file is malicious. Never run an untrusted executable just because its metadata looks normal.
Can it detect a fake file extension?
Yes for many common formats. The inspector checks magic bytes and container signatures, so a file named like an image can still be identified as a PDF, ZIP, executable or other supported format.
Can I save the inspection results?
Yes. After inspection you can copy the report or download it as TXT, PDF or JSON.
Is the report a malware scan?
No. It can reveal structural warning signs such as extension mismatches, executable content, PDF JavaScript markers, macros or executable files inside a ZIP, but it does not replace antivirus or sandbox analysis.
Use inspection as a clue, not a guarantee
A filename extension is only a label. The File Inspector also looks at file signatures, readable structure, hashes and selected metadata so you can compare what a file is called with what its bytes suggest. That is useful when a download has the wrong extension, when you want to document a checksum, or when you want to see whether an image still contains EXIF or GPS-related fields.
Inspection does not make an unknown file safe. A valid signature can still belong to a malicious or damaged file, and entropy or metadata findings are indicators rather than a malware verdict. For untrusted executables, archives or documents, use an up-to-date security product and an isolated environment in addition to basic inspection.
Practical checks
- Compare the detected type with the filename extension before opening suspicious downloads.
- Record a SHA-256 hash when you need to verify that the same file has not changed later.
- Treat privacy findings such as location metadata as a prompt to review the file before sharing.
Practical walkthrough · file inspector
Check whether a renamed download is what it claims
Example task: Someone sends a file labelled photo.jpg, but you want to know whether its header looks like JPEG data.
Try this workflow
- Select the file and compare detected signature with its extension.
- Review relevant metadata and any flags before opening it in another program.
- Export or record the findings if you need to discuss the file with a sender.
What to expect
A signature mismatch is a useful clue that the extension may be wrong, not proof of malicious behavior.
When to take extra care
The inspector is not an antivirus engine, malware sandbox or guarantee that a file is safe to open.