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Documentation Index

Fetch the complete documentation index at: https://docs.intelliprint.net/llms.txt

Use this file to discover all available pages before exploring further.

Learn about the envelope and postcard sizes available for your print jobs.
For complete parameter documentation, see the Print Jobs API Reference.

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Envelope Sizes (Letters)

Intelliprint automatically selects the appropriate envelope based on your content, but you can specify a preferred size using postage.ideal_envelope.

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Available Envelope Sizes

SizeDimensionsCapacityBest For
C5162 x 229mmUp to 30 sides (15 sheets folded A4)Standard letters (default)
C4229 x 324mmUp to 100 sides (50 sheets unfolded A4)Multi-page documents
C4+250 x 353mmUp to 500 sides (250 sheets A4)Large documents
A4 BoxCustom boxUp to 3600 sides (1800 sheets A4)Very large mailings
Automatic selection: Intelliprint may upgrade to a larger envelope if your content doesn’t fit the specified size. The actual envelope used is returned in the letters[].envelope field.

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C5 Envelope (Default)

The most common envelope for standard letters:
  • Holds up to 15 sheets of A4 paper (folded)
  • Window position: 20mm from left, 45mm from top
  • Window size: 90mm × 40mm
  • Suitable for 1-30 page letters
const printJob = await ip.prints.create({
  testmode: true,
  content: '<h1>Standard Letter</h1>',
  recipients: [{address: {/* ... */}}],
  
  postage: {
    service: 'uk_second_class',
    ideal_envelope: 'c5'  // Default - can omit
  },
  
  confirmed: true
});

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C4 Envelope

Larger envelope for multi-page documents:
  • Holds up to 50 sheets of A4 paper (unfolded)
  • No folding required for A4 pages
  • Suitable for 30-100 page documents
const printJob = await ip.prints.create({
  testmode: true,
  file: fs.createReadStream('./report.pdf'),  // 40 pages
  recipients: [{address: {/* ... */}}],
  
  postage: {
    service: 'uk_first_class',
    ideal_envelope: 'c4'  // Larger envelope for multi-page
  },
  
  confirmed: true
});

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C4+ Envelope

For large document packages:
  • Holds up to 250 sheets of A4 paper
  • Suitable for 100-500 page documents
  • Higher postage costs due to size

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A4 Box

For very large mailings:
  • Holds up to 1800 sheets of A4 paper
  • Packaged in a box for protection
  • Suitable for 500-3600 page documents
  • Premium postage service
Large envelopes increase costs: Larger envelopes have higher postage and handling costs. Use the smallest envelope that fits your content.

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Postcard Sizes

Postcards are sent without envelopes (or optionally in envelopes for A5).

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Available Postcard Sizes

SizeDimensionsEnvelopedBest For
A6148mm × 105mmNoCost-effective bulk mail (default)
A5210mm × 148mmNoPremium larger postcards
A5 Enveloped210mm × 148mmYesPrivate/confidential messages

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A6 Postcard (Default)

The most economical postcard option:
  • Standard postcard size
  • No envelope (arrives as-is)
  • Perfect for marketing campaigns
  • Lower postage costs
const printJob = await ip.prints.create({
  testmode: true,
  type: 'postcard',
  
  file: fs.createReadStream('./postcard.pdf'),
  recipients: [{address: {/* ... */}}],
  
  postage: {
    service: 'uk_second_class',
    ideal_envelope: 'postcard_a6'  // Default for postcards
  },
  
  confirmed: true
});

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A5 Postcard

Larger postcard for premium impact:
  • 50% larger than A6
  • More space for content and images
  • Higher visibility
  • Higher postage costs
const printJob = await ip.prints.create({
  testmode: true,
  type: 'postcard',
  
  file: fs.createReadStream('./large-postcard.pdf'),
  recipients: [{address: {/* ... */}}],
  
  postage: {
    service: 'uk_first_class',
    ideal_envelope: 'postcard_a5'  // Larger postcard
  },
  
  confirmed: true
});

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A5 Enveloped Postcard

A5 postcard sent in an envelope for privacy:
  • Same size as A5 postcard
  • Sealed in envelope before mailing
  • Keep message private until opened
  • Suitable for confidential communications
const printJob = await ip.prints.create({
  testmode: true,
  type: 'postcard',
  
  file: fs.createReadStream('./private-message.pdf'),
  recipients: [{address: {/* ... */}}],
  
  postage: {
    service: 'uk_first_class',
    ideal_envelope: 'postcard_a5_enveloped'  // In envelope
  },
  
  confirmed: true
});
Privacy: Enveloped postcards are sealed in an envelope before mailing, keeping the message private until opened by the recipient.

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Postcard Constraints

Postcard limitations:
  • Can only use uk_second_class or uk_first_class postage
  • No backgrounds or letterheads
  • No extra documents
  • No double-sided printing options (always single-sided)
  • No inserts
  • Always printed in color

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Cost Considerations

Envelope/postcard size affects total cost:
SizeBase CostPostage CostTotal Impact
C5StandardStandardBaseline
C4HigherHigher+30-50%
C4+Much higherMuch higher+100-150%
A4 BoxPremiumPremium+200%+
A6 PostcardLowLowMost economical
A5 PostcardMediumMedium+20-30% vs A6
Use testmode: true to see exact costs for different envelope sizes before sending live print jobs.Learn more about cost calculation →

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Specify Envelope Size

const printJob = await ip.prints.create({
  testmode: true,
  content: '<h1>Multi-page Letter</h1>',
  recipients: [{address: {/* ... */}}],
  
  postage: {
    service: 'uk_first_class',
    ideal_envelope: 'c4'  // Prefer larger envelope
  },
  
  confirmed: true
});

console.log('Actual envelope used:', printJob.letters[0].envelope);

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Best Practices

In most cases, let Intelliprint automatically select the envelope size based on your content. It will choose the most economical option that fits.
Always test with your actual content in test mode to verify the envelope size and cost before sending live print jobs.
Larger envelopes have significantly higher postage costs. Keep content concise to fit in smaller envelopes when possible.
Postcards are more economical than letters for bulk marketing campaigns and have high visibility (no envelope to open).

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Next Steps

Postage Services

Learn about delivery options

Attaching Extra Documents

Add multiple documents to letters

Understand Costs

Calculate printing and postage costs

API Reference

Complete API documentation