generated: '2026-08-13'
method: searched
source: https://www.zoho.com/campaigns/help/developers/
docs:
  - https://www.zoho.com/campaigns/help/developers/
  - https://www.zoho.com/campaigns/help/emailapi/error-codes.html
name: Zoho Campaigns API Rate Limits
description: Rate limiting policies for the Zoho Campaigns REST API v1.1 and the Email API v2
url: https://www.zoho.com/campaigns/help/developers/
limit_count: 3
limits:
  - name: Standard API Rate Limit
    description: Maximum API calls allowed within a 5-minute window
    requests: 500
    window: 5 minutes
    scope: per account
    api: Zoho Campaigns API v1.1

  - name: Lockout Period
    description: If the rate limit is exceeded, API access is suspended for 30 minutes
    lockout_duration: 30 minutes
    scope: per account
    api: Zoho Campaigns API v1.1
    note: Other Zoho APIs remain accessible unless their own lock period has been reached

  - name: Email API report date range
    description: Reporting endpoints reject a date range wider than 90 days
    window: 90 days
    scope: per request
    api: Zoho Campaigns Email API v2
    error_code: '400303'
    error_message: Date range exceeds the limit of 90 days

quota_limits:
  - name: API keys per user
    limit: 20
    api: Zoho Campaigns Email API v2
    source: https://www.zoho.com/campaigns/help/emailapi/authentication.html
  - name: Attachments per transmission
    limit: 5
    api: Zoho Campaigns Email API v2
    error_code: '400040'
  - name: Total attachment size per transmission
    limit: 5 MB
    api: Zoho Campaigns Email API v2
    error_code: '400041'
  - name: Single-request suppression-list size
    limit: not published
    api: Zoho Campaigns Email API v2
    error_code: '400404'
    error_message: Limit for a single API request has been exceeded

response_headers:
  published: false
  headers: []
  retry_after: false
  status_on_exhaustion: not published
  note: >-
    Zoho publishes the numeric limit but documents NO rate-limit response
    headers (no X-RateLimit-*, no RateLimit-*, no Retry-After) and no status
    code for exhaustion. Because the v1.1 API returns HTTP 200 with an in-body
    numeric code even on failure, a client has no runtime budget signal at all
    and can only detect the lockout after it has already been applied.

token_limits:
  - name: Access Token Expiry
    description: OAuth 2.0 access tokens expire after one hour
    duration: 1 hour
    refresh: Use refresh token to obtain a new access token
    source: https://www.zoho.com/campaigns/help/developers/access-token.html

notes:
  - Rate limits apply per account across all API keys
  - Exceeding the limit triggers a 30-minute cooldown for the Zoho Campaigns API
  - Other Zoho product APIs are not affected by a Zoho Campaigns rate-limit lockout
  - Rate limits may vary by plan tier; consult official docs for current values
  - API documentation reference: https://www.zoho.com/campaigns/help/developers/