File name safety
The File Attachment Checker finds spaces, special characters, long names and confusing dots that can cause older forms or strict validators to reject an upload.
Free File Attachment Checker
File Attachment Checker for safer uploads and submissions before you attach, upload or submit
Upload PDF, DOCX, PNG, JPG, ZIP, CSV and common document files to the File Attachment Checker before sending an email, job application, school upload, visa document upload or website form. The browser-side report checks size, extension, MIME type, detected type, file name safety and whether a form may reject the attachment.
Browser-side attachment check
Upload files to the File Attachment Checker
Choose the preset that matches the destination, then add one or more attachments. The File Attachment Checker reads file names, sizes, browser MIME values and lightweight file signatures locally.
Upload scenario preset
Your files stay in this browser tab. The File Attachment Checker does not upload attachments to inspect them.
Try sample attachment checks
File Attachment Checker results will appear here
Upload attachments or try a sample to see file size, file name, extension, MIME type, detected type, rename, compression and form-readiness checks.
File Attachment Checker workflow before upload
The File Attachment Checker turns a folder of attachments into a practical pre-submission report for email, forms, school portals, job applications and visa uploads.
File Attachment Checker upload presets
Start by choosing email attachment, job application, school upload, visa document upload or website form upload. The File Attachment Checker adjusts size and type checks for that destination.
File Attachment Checker result report
Review whether each attachment is too large, has an unsafe name, mismatches its detected type, needs renaming, needs compression or may be rejected by a strict form.
File Attachment Checker submission workflow
Use the File Attachment Checker before sending deliverables, uploading school files, attaching visa scans or submitting website forms, then rename or compress files before the final upload.
File Attachment Checker features for upload QA
Use the File Attachment Checker when a file looks fine on your computer but may fail after a platform, form or email service applies its own upload rules.
Extension and type check
Compare the extension with browser MIME values and lightweight file signatures for PDF, DOCX, PNG, JPG, ZIP and CSV-style files.
Size limit review
The File Attachment Checker reviews per-file and total-size risk against practical presets for email attachments, job applications, school uploads, visa uploads and website forms.
Form rejection risk
See whether the attachment may fail because it is too large, not allowed by the preset, missing a MIME value or mismatched to its extension.
Rename suggestions
Get a safer file name that keeps letters, numbers, dots, underscores and hyphens before submitting to a strict upload form.
Compression guidance
Find attachments that should be compressed, split or re-exported before they hit an email or portal size limit.
How to use the File Attachment Checker before submission
The File Attachment Checker is a browser-side preflight. It catches common upload blockers, but the final rule is still the exact requirement from the platform, school, employer or visa center.
01
Pick a File Attachment Checker preset
Choose the destination that best matches your task: email attachment, job application, school upload, visa document upload or website form upload. The preset changes practical size and extension checks.
- Use visa for scanned documents with tighter limits
- Use website form upload when no specific platform is known
02
Upload attachments to the File Attachment Checker
Add the files you plan to submit. The checker reads browser metadata and a small local byte sample to compare file name, extension, MIME type and detected type.
Browser MIME values can be blank or wrong, so the result is best treated as a practical warning system rather than a forensic file validator.
Upload files 03
Fix File Attachment Checker warnings
Rename unsafe files, compress large attachments, convert mismatched files again and re-run the check before you submit the final set.
When a portal lists its own maximum size or accepted extensions, use that official requirement over the preset and keep the File Attachment Checker report as an early warning.
Review reportFile Attachment Checker FAQ
Answers about privacy, accuracy, accepted file types, MIME type checks, upload limits and what to do when the File Attachment Checker flags a file.
What does the File Attachment Checker inspect?
The File Attachment Checker inspects file name patterns, extension, file size, browser MIME type and a lightweight local signature for common formats such as PDF, PNG, JPG, ZIP and DOCX. It then reports rename, compression and upload-readiness advice.
Does the File Attachment Checker upload or store my attachments?
No. The check runs in your browser tab. The File Attachment Checker reads only local file metadata and a small local byte sample needed for type detection.
Can the File Attachment Checker guarantee that a form will accept my file?
No. It checks common rejection risks, but each employer, school, visa center, email service or website form may enforce its own limits, malware scan rules and accepted file list.
Why can extension, MIME type and detected type disagree?
A file can be renamed without changing its contents, and browsers can provide blank or generic MIME values. A mismatch means you should re-export or rename the attachment before submission.
Which files can I check?
The File Attachment Checker is designed for common upload attachments such as PDF, DOCX, PNG, JPG, ZIP, CSV, text files and office-style documents. It can still show size and name checks for other files, but type detection may be limited.
What should I do if the File Attachment Checker says a file is too large?
Compress the file, export a smaller PDF or image, split the upload into separate files if the destination allows it, or follow the platform's official file-size instruction when it is available.
Run the File Attachment Checker before the final upload
Use the File Attachment Checker to review attachment size, file name safety, extension, MIME type and detected type before a form or email service rejects the upload.
Fix the report, recheck the final files, then submit with fewer last-minute surprises.
Free File Attachment Checker for PDF, DOCX, PNG, JPG, ZIP, CSV and common upload files.