Upload a file and find out exactly what's wrong with it: which PNG chunk's checksum fails, where a JPEG's markers stop making sense, whether a PDF's cross-reference table actually resolves — backed by a byte-level heatmap of the whole file.
If you're here because something threw one of these, this tool shows you exactly what's wrong and how much is recoverable:
Structural validation confirms a file's containers, chunks, and checksums are intact — it doesn't decode the actual payload. Specifically: PNG's deflate/zlib-compressed pixel data isn't decompressed or checked for validity, only its chunk boundaries and CRC-32s. JPEG's entropy-coded scan data (after the SOS marker) isn't decoded — only the marker segments before it. ZIP entries aren't decompressed to verify their contents match their declared CRC-32; for that, use the ZIP Inspector, which does check per-entry local headers. A file can pass every check here and still fail to open if the compressed payload itself is corrupted in a way that doesn't touch the container structure.