specification: API Commons Rate Limits
specificationVersion: '0.1'
schema: https://raw.githubusercontent.com/api-evangelist/interface-research/main/schema/api-commons.yml#/$defs/RateLimits
provider: MailerSend
providerId: mailersend
created: '2026-05-08'
modified: '2026-08-13'
generated: '2026-08-13'
method: searched
source: https://developers.mailersend.com/general
reconciled: true
tags:
  - Email
  - Transactional
  - SMS
  - Templates
  - API
  - Rate Limiting
  - Quotas
  - Throttling
description: >-
  MailerSend publishes two independent throttles on api.mailersend.com/v1: a per-minute rate limit that
  varies by endpoint, and a per-account daily request quota that varies by plan. Both surface as HTTP 429
  and both are signalled in response headers on every request, so an agent can read remaining budget
  without waiting to be rejected.
notes: >-
  Harvested verbatim from the "Rate limits" and "Daily request quota" sections of the General API
  resources page. The quota endpoint GET /v1/api-quota reports quota/remaining/reset and does not itself
  count against the quota.
sources:
  - https://developers.mailersend.com/general
  - https://developers.mailersend.com/guides/checking-api-quota
responseCodes:
  throttled: 429
  message_rate_limit: 'Your account reached its rate limit of {limit} requests/min. Please wait before trying again. #MS42903'
  message_quota: 'Your account reached its API daily quota limit. Upgrade to increase it. #MS42901'
headers:
  rate_limit:
    - name: x-ratelimit-limit
      description: Requests permitted in the current one-minute window.
    - name: x-ratelimit-remaining
      description: Requests left in the current one-minute window.
    - name: x-ratelimit-reset
      description: Unix timestamp at which the one-minute window resets.
    - name: retry-after
      description: Seconds the client must wait before retrying after a 429.
  daily_quota:
    - name: x-apiquota-remaining
      description: Requests remaining in the account's daily quota.
    - name: x-apiquota-reset
      description: ISO 8601 timestamp at which the daily quota resets (midnight UTC).
quota_endpoint:
  method: GET
  url: https://api.mailersend.com/v1/api-quota
  counts_against_quota: false
  response_fields: [quota, remaining, reset]
  docs: https://developers.mailersend.com/guides/checking-api-quota
limits:
  - name: General API requests
    scope: account
    metric: requests
    limit: 60
    window: minute
    endpoints: all endpoints except the email endpoints listed below
  - name: Email send
    scope: account
    metric: requests
    limit: 120
    window: minute
    endpoints: POST /v1/email
  - name: Bulk email send
    scope: account
    metric: requests
    limit: 10
    window: minute
    endpoints: POST /v1/bulk-email
  - name: Activity
    scope: account
    metric: requests
    limit: 10
    window: minute
    endpoints: GET /v1/activity
  - name: SMTP
    scope: account
    metric: requests
    limit: 120
    window: minute
    endpoints: SMTP relay
daily_quotas:
  - plan: Trial
    requests_per_day: 100
  - plan: Hobby
    requests_per_day: 1000
  - plan: Starter
    requests_per_day: 100000
  - plan: Professional
    requests_per_day: 500000
  - plan: Enterprise
    requests_per_day: 500000
quota_reset: daily at midnight UTC
limit_count: 5
policies:
  - name: Retry-After
    description: >-
      On 429 the client must wait the number of seconds given in the retry-after header before retrying;
      MailerSend documents exponential backoff with jitter as the recommended client behaviour.
  - name: Avoid failed validation
    description: MailerSend advises against repeating requests that fail 422 validation, as they consume quota.
  - name: Use bulk endpoint
    description: High-volume senders are directed to POST /v1/bulk-email rather than looping POST /v1/email.
maintainers:
  - FN: Kin Lane
    email: kin@apievangelist.com