Image MIME Reference
FastBid
FastBid Sheet
image/vnd.fastbidsheet
VS
Extended Image File Format
image/vnd.xiff
XIFF
A complete technical comparison of FastBid Sheet and Extended Image File Format — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | FastBid | XIFF |
|---|---|---|
| Transparency (Alpha) | ✕ No | ✕ No |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | ✕ No | ✕ No |
| EXIF Metadata | ✕ No | ✕ No |
| ICC Color Profile | ✕ No | ✕ No |
FastBid Sheet
image/vnd.fastbidsheet
Extension
.fbs
Container
Proprietary FastBid Container
Compression
Proprietary
Algorithm
Unknown
Color Depth
Unknown
Developed by
FastBid, Inc. (Scott Becker)
Released
Late 1990s
Magic Bytes
Unknown (Proprietary)
Extended Image File Format
image/vnd.xiff
Extension
.xif
Container
TIFF-based Proprietary Container
Compression
CCITT Group 3 / Group 4 / LZW / Uncompressed
Algorithm
CCITT Group 4LZWNone
Color Depth
1-bit (Monochrome), 8-bit (Grayscale), 24-bit (RGB)
Developed by
Keyfile Corporation
Released
1994
Magic Bytes
49 49 2A 00 or 4D 4D 00 2A
Browser Support Comparison
| Browser | FastBid | XIFF |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
FastBid
FastBid Strengths
- Historically allowed the FastBid application to securely associate and load proprietary construction plans within its ecosystem
Limitations
- Completely obsolete and unsupported in modern software environments
- The official IANA registration of the .fbs extension causes widespread false positives, breaking modern parsers, text editors, and AI SDKs attempting to read FlatBuffers schemas
XIFF
XIFF Strengths
- Pioneered early enterprise document workflow integration by binding administrative routing data directly to the document image file
- Leveraged efficient fax compression standards to keep storage requirements low on 1990s server infrastructure
Limitations
- Completely proprietary and obsolete; Keyfile Corporation's software ecosystem no longer exists
- Causes widespread MIME type identification conflicts due to sharing the exact same binary header signature as standard TIFF files
- Zero support in modern operating systems or web browsers
When to choose which format
FastBid
Use FastBid when…
- Legacy Construction Blueprints
- FastBid Estimating Software
- Causing .fbs MIME Type Conflicts (FlatBuffers)
XIFF
Use XIFF when…
- Keyfile Enterprise Document Management
- Legacy Corporate Workflow Archival
- Scanned Multi-page Document Routing