Platform creative delivery

Email
Creative Specifications

Independent email-delivery specification. Requirements come from mailbox providers (Gmail sender guidelines) and industry convention — NOT from StackAdapt: StackAdapt's email offering is an owned sending product with a WYSIWYG editor and publishes no creative specification, and StackAdapt does not document email as a media-activation channel.

Formats supported
HTML Email
Primary campaign uses
Not specified by platform
Last verified
Aug 2, 2026
Recommended delivery package
Not specified by platform
Catalog status
Current
Email creative formats
Published catalog 5Published August 2, 2026

Quick delivery checklist

What to send Cphere

  • Final platform-ready creative
  • Approved copy and CTA
  • Destination URL and tracking parameters
  • Brand and legal requirements

Canonical records

Formats and placements

HTML Email

Published format-level guidance.

Current

Required

Not specified by platform

Recommended

Not specified by platform

Placement-dependent

Not specified by platform

Cphere best practice

Not specified by platform

Marketing Email

Deliverability requirements come from mailbox providers; visual conventions are industry guidance.

Required
Message Format
Format messages per RFC 5322; HTML must follow HTML standards; never hide content with HTML or CSS; links must be visible and predictable
Unsubscribe
Bulk senders (5,000+/day to Gmail) must support one-click unsubscribe (List-Unsubscribe headers) and a visible unsubscribe link
Recommended

Not specified by platform

Placement-dependent

Not specified by platform

Cphere best practice
Body Width
600–640 pixels pixels — Industry convention (Litmus); not a platform mandate.
Image Weight
Individual images under 200 KB; total email assets around 1 MB or less — Industry convention (Litmus); not a platform mandate.
Html Weight
Keep the HTML under roughly 102 KB to avoid Gmail clipping — Observed Gmail behavior documented by industry sources; not stated in Google's official guidelines.
Accessibility
Alt text on all images; live text over image-only text; test light and dark mode with transparent-safe PNGs — Industry convention (Litmus).

Delivery detail

File, copy, audio, and destination requirements

File requirements

Not specified by platform

Copy requirements

Not specified by platform

Audio requirements

Not specified by platform

Tracking requirements

Not specified by platform

Landing-page requirements

Not specified by platform

Prohibited or unsupported elements

No prohibited-element list is published for this record.

Interface-aware delivery

Safe zones

No verified safe-zone diagram is published for this placement. Do not infer pixel-safe areas.

Clearly separated guidance

Recommended best practices

No additional Cphere best-practice copy is published for this record.

Source transparency

Sources and verification

Last verified: Aug 2, 2026. Platform requirements may change; check these official references before final delivery.

Publisher, exchange, and standards-body trademarks referenced in this specification belong to their respective owners. Cphere does not imply endorsement or partnership.