Letters
What it is
Letters are 8.5×11-inch mailers sent in envelopes. Two formats are available:
- Windowed letter - the recipient's address shows through a transparent window cut into the envelope.
- Windowless letter - no address window; the address is printed on the envelope directly.
Both formats support two send modes:
- Cover page mode — a designed cover page using an Image Template and a Message Template (handwritten-style font). You can optionally attach additional pages as a PDF appended after the cover. Additional pages can be printed front/back.
- PDF-only mode — the entire mailer is a PDF you upload. No Image Template or Message Template is used; your PDF is the complete letter. All pages can be printed front/back.
Both formats support Standard and First Class postage and replacement variable personalization.
When to use it
- Formal communications where a traditional letter format builds credibility (B2B, legal notices, nonprofit appeals)
- Long-form content that needs more space than a postcard - proposals, newsletters, multi-page donor letters
- Situations where the envelope presentation matters: windowed letters look like official mail and get opened
- Nonprofit fundraising appeals and donor acknowledgments
Windowed letters
For windowed letters, the address block on your printed letter must fall within the window zone. The editor shows the window zone as an overlay on the design canvas.
- Keep all address content inside the window zone boundary.
- Do not place any other design elements inside the window zone - they will be visible through the envelope.
- Use a white or light background behind the address area.
In cover page mode, the window zone constraint applies to the cover page. In PDF-only mode, your PDF is the entire letter — ensure the address block on page 1 of your PDF falls within the window zone.
Windowless letters
Windowless letters have no window constraint - full design freedom across the entire letter. The address is handled separately by the printing process. Windowless letters are mailed with a real postage stamp, and the recipient's address is printed on the envelope in a handwriting font. The envelope color cannot be modified.
Use the windowless format when:
- Your design spans the full page without an address zone.
- You're sending a newsletter or multi-page document as a PDF.
Send modes
Both windowed and windowless letters support the same two send modes.
Cover page mode
Your first page is a designed cover using an Image Template and a Message Template (handwritten-style font). You can optionally attach additional pages as a PDF appended after the cover. Additional pages can be printed front/back.
PDF-only mode
Your entire mailer is a PDF you upload. There is no cover Image Template or Message Template — your PDF is the complete letter. All pages can be printed front/back. This is the right mode for newsletters, CMA reports, multi-page proposals, and any document that already exists as a formatted PDF file.
See Send a PDF Letter for a step-by-step walkthrough of the PDF-only workflow.
Multi-page pricing
The first physical page is included in the base per-piece price. Each additional physical page adds $0.20 per piece. A physical page is one sheet of paper — a page printed front/back counts as one physical page, not two.
Example: a 4-page PDF where each page is a separate side (2 sheets, printed front/back) = base price + $0.20 × 1 additional physical page.
Tips & best practices
- Use a clean, professional letterhead for windowed letters - the window creates an impression of official correspondence.
- For nonprofit appeals, a personalized opening line with
%FIRST_NAME%and a handwritten-style signature can meaningfully increase response rates. - For PDF newsletters, design at 8.5×11 with 0.5-inch margins to avoid content being trimmed.
Limits & gotchas
- Both send modes (cover page and PDF-only) are available for windowed and windowless letters.
- Additional pages cost $0.20 per additional physical page. A sheet printed front/back is one physical page.