For developers

Link reference

Every rollcast://print parameter, limit and a link to try.

URL

rollcast://print?type=<raw|text|html>&data=<base64>&printer=<id>

Parameter	Meaning
type	raw (default, also escpos): ESC/POS bytes. text (also txt): UTF-8 text. html (also htm): UTF-8 HTML document.
data	Required. Base64 of the payload. Standard or URL-safe alphabet, padding optional. Percent-encode standard base64, because '+' would become a space.
printer	Optional printer ID (up to 128 characters). If it is missing or unknown, the default printer is used.

Limits

Limit	Value
Query length	2 MB (2,097,152 characters). Android may fail near 1 MB, so keep links small.
Rate	1 link per second; extras are dropped.
Allow web prints	Must be on for every rollcast:// link, from browsers and apps.
Shared files	20 MB per file, up to 32 files. Always printed on the default printer.

From web pages, use this form so users without RollCast go to a fallback page or the Play Store.

URL

intent://print?type=text&data=<base64>#Intent;scheme=rollcast;package=com.rollcast.app;S.browser_fallback_url=<percent-encoded https URL>;end

This link prints "Hello from RollCast!" on the default printer:

URL

rollcast://print?type=text&data=SGVsbG8gZnJvbSBSb2xsQ2FzdCE

Testers can send it from a computer with adb:

Shell

adb shell "am start -a android.intent.action.VIEW -d 'rollcast://print?type=text&data=SGVsbG8gZnJvbSBSb2xsQ2FzdCE'"

Tip

The inner single quotes stop the phone's shell from treating '&' as a command separator.

Message	Meaning
Sent to printer	The job was accepted.
Printing from web links is disabled in RollCast settings	Turn on "Allow web prints".
Too many print requests	More than one link per second.
Nothing to print: …	The link was rejected. The reason follows (missing data, invalid base64, unknown type, payload too large).
No printer configured. Open RollCast to add one.	Notification: the printer ID was missing or unknown and there is no default printer.