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About this tool
Build a file naming rule for logos, exports and campaign assets, validated against POSIX, Windows and S3 filename limits.
Brand Asset Naming Convention Builder turns a chosen set of tokens — brand, campaign, asset type, variant, dimensions, date and version — into a single filename pattern, then validates the result against the limits that actually break files: the POSIX portable filename character set, the Windows reserved device names, the 255-byte path component limit shared by NTFS, ext4 and APFS, the 260-character legacy MAX_PATH, and the 1024-byte Amazon S3 object key cap. Design and marketing teams get a copyable rules document plus worked examples across a real export set.
Open Brand Asset Naming Convention Builder on AltFTool — it loads instantly in your browser.
Under Tokens and order, tick the tokens you want — Brand, Project or campaign, Asset type, Descriptor, Variant, Colour mode, Dimensions, Locale, Date, Version — and use the arrow buttons to reorder them.
Set Separator, Case, Date format, Version number and Version digits under Style rules, then enter the Sample values and the Folder path (for the 260-character check).
Example filename shows the result and its pattern above Filename length (limit 255 bytes), Bytes (UTF-8), Full path length (Windows MAX_PATH 260) and POSIX portable, with any reserved-name issues listed; Copy rules copies the convention as Markdown.
Every token value is sanitized to the portable filename character set as you type, then the finished name is still checked against the reserved-name, length and path limits sanitizing alone can't fix.
ISO 8601 dates and padded versions make an alphabetical file list a chronological one.
Copies out as a Markdown page you can paste straight into a brand book or team wiki.
Stick to A-Z, a-z, 0-9, dot, underscore and hyphen — the POSIX portable filename character set defined in IEEE Std 1003.1. Windows additionally forbids < > : " / \ | ? * and control characters, so anything outside the portable set risks failing on at least one platform.
A single path component is capped at 255 bytes on NTFS, ext4 and APFS, and the legacy Windows MAX_PATH limits a whole path to 260 characters. In practice keep filenames under about 80 characters so they are not truncated in file browsers and email clients.
Use hyphens if the file may ever be served from a URL — search engines treat a hyphen as a word separator and an underscore as a joiner. Underscores are equally safe on disk, but they can be hidden by the underline in a hyperlink.
Windows reserves the device names CON, PRN, AUX, NUL, COM1-COM9 and LPT1-LPT9, and rejects them even with an extension, so CON.png cannot be created. It also silently strips a trailing dot or space from the very end of the name, so a file saved as "logo.png." or "logo.png " is written to disk as plain "logo.png" instead.