generated: '2026-08-26'
method: searched
source: https://docs.paubox.com/email-api/limits
description: >-
  Paubox publishes hard sending limits (recipients, attachment size, batch size) and plan
  quotas with overage pricing, but does NOT publish a numeric request rate limit and
  does NOT document any rate-limit response header. An agent gets no runtime pacing
  signal — only the 429 itself.
docs: https://docs.paubox.com/email-api/limits
limit_count: 4
rate_limits:
  - name: Max recipients per message
    scope: per-request
    api: Paubox Email API
    limit: 100
    unit: recipients
    window: null
    operations: [sendMessage]
    source: https://docs.paubox.com/email-api/limits
  - name: Max attachment size per message
    scope: per-request
    api: Paubox Email API
    limit: 50
    unit: MB (total across all attachments)
    window: null
    operations: [sendMessage, sendBulkMessages]
    source: https://docs.paubox.com/email-api/limits
  - name: Recommended bulk batch size
    scope: per-request
    api: Paubox Email API
    limit: 50
    unit: messages per request
    window: null
    enforced: false
    note: Published as a provider recommendation, not a hard cap.
    operations: [sendBulkMessages]
    source: https://docs.paubox.com/email-api/limits
  - name: Max form submission request size
    scope: per-request
    api: Paubox Forms API
    limit: 250
    unit: MB (total request size including attachments)
    window: null
    source: https://docs.paubox.com/cli/commands
    note: Stated in the CLI reference for `paubox forms submit --attach`.

quota_limits:
  note: >-
    Monthly send quotas are plan-attached rather than rate limits. Exceeding them does not
    return 429 — it bills overage. See plans/paubox-plans-pricing.yml.
  tiers:
    - plan: Free
      monthly_emails: 300
      overage_per_email_usd: null
    - plan: Pro
      monthly_emails: 10000
      overage_per_email_usd: 0.0130
    - plan: Pro
      monthly_emails: 30000
      overage_per_email_usd: 0.0130
    - plan: Pro
      monthly_emails: 50000
      overage_per_email_usd: 0.0100
    - plan: Pro
      monthly_emails: 100000
      overage_per_email_usd: 0.0098
    - plan: Pro
      monthly_emails: null
      overage_per_email_usd: null
      note: Custom volume — priced on request.

exhaustion:
  status_code: 429
  status_title: Too Many Requests
  documented_at: https://docs.paubox.com/email-api/errors
  guidance: 'Provider guidance is verbatim: "back off and retry."'

response_headers:
  documented: false
  ratelimit_headers: []
  retry_after: false
  note: >-
    No RateLimit-*, X-RateLimit-* or Retry-After header is documented anywhere in
    docs.paubox.com, and no rate-limit header appears in any response definition in the
    three OpenAPI documents. The 429 status is the only runtime signal published. This is
    the largest single agent-readiness gap in the Paubox surface: a client cannot pace
    itself, only react after being refused.

gaps:
  - No numeric requests-per-second or requests-per-minute limit is published for any API.
  - No rate-limit headers are documented, so backoff interval is entirely client-chosen.
  - 429 is not declared as a response on any operation in any OpenAPI document.