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Limitations & Supported Channels

Overview

Understanding the limits and rate limits in Bird Campaigns helps you plan and execute successful marketing campaigns. This guide covers campaign limits, sending rate limits, channel-specific restrictions, and best practices for working within these constraints.

Rate Limits

Rate limits control how quickly messages are sent to protect deliverability and comply with channel provider requirements.
How rate limiting works:
  • Messages are queued and sent at the allowed rate
  • Bird automatically throttles sends to stay within limits
  • Large campaigns may take longer to complete if they exceed rate limits

Channel-Specific Rate Limits

Rate limits vary by channel and are determined by both Bird's infrastructure and external channel provider restrictions.
SMS
Default: 200 messages per second
Carrier limits: Additional limits may apply based on destination carrier
RCS (Rich Communication Services)
Default: 80 messages per second
Carrier limits: Varies by carrier and region
Considerations:
  • Higher limits available for verified brands
  • Rate limits may be lower during initial brand verification period
WhatsApp Business
Default: 80 messages per second
Tier-based limits: WhatsApp uses a tiered messaging limit system
Quality-based limits: Messaging limits adjust based on message quality ratings
Tier structure:
  • Tier 1: 1,000 unique customers per 24 hours
  • Tier 2: 10,000 unique customers per 24 hours
  • Tier 3: 100,000 unique customers per 24 hours
  • Tier 4 (Unlimited): Unlimited unique customers per 24 hours
Important: Limits reset every 24 hours and are based on unique customer conversations, not total messages.
Learn more: WhatsApp Business Channel Documentation
Email
Default: 400 messages per second
ISP considerations:
  • Major ISPs (Gmail, Outlook) may apply their own receiving limits
  • Warm-up schedules required for new sending domains
Push Notifications
Mobile push: 400 messages per second
Platform limits: Additional limits may apply from Apple (APNs) and Google (FCM)

Message Size Limits

Character and Content Limits

SMS:
  • Standard: 160 characters per message segment
  • Unicode/emoji: 70 characters per message segment
  • Maximum segments: 10 (1,600 standard characters or 700 unicode characters)
RCS:
  • Text: 3,072 characters
  • Image size: 500 KB per image
  • Video size: 1.5 MB per video
  • Rich cards: Up to 10 cards per carousel
WhatsApp:
  • Text: 1024 characters
  • Media file size: 16 MB for images, 16 MB for videos, 100 MB for documents
Email:
  • Recommended Size: 100 KB to avoid clipping and delivery issues
  • Total message size: 10 MB including attachments
  • Attachment size: 25 MB total across all attachments
  • Subject line: 256 characters recommended (no hard limit)
Push Notifications:
  • iOS title: 75 characters
  • iOS body: 235 characters
  • Android title: 50 characters
  • Android body: 240 characters

Supported Channels

Bird Campaigns supports the following messaging channels. Click each channel for detailed documentation:

Marketing Channels