---
title: "Deliverability lint without sending: a 0-100 placement score plus every finding with its fix."
method: POST
path: "/emails/lint"
tags: ["emails"]
---

# Deliverability lint without sending: a 0-100 placement score plus every finding with its fix.

`POST /emails/lint`

## Request

- Base URL: `https://api.agentisend.com`
- URL: `https://api.agentisend.com/emails/lint`
- Auth: HTTP bearer

## Headers

- `Idempotency-Key` string
- `Resend-Idempotency-Key` string

## Request body

- PostEmailsLintBody
  - `from` string, required: Sender address the lint reads.
  - `to` string[], required: Recipient addresses.
  - `subject` string: Subject. Empty is allowed here, because this call sends nothing.
  - `html` string: HTML body to score.
  - `text` string: Plain-text body to score.
  - `headers` object: Headers to score.

## Response `200`

Success

- PostEmailsLintReply
  - `score` integer, required
  - `findings` object[], required
    - `rule` string, required
    - `severity` 'error' | 'warning' | 'info', required
    - `message` string, required
    - `fix` string, required

## Other responses

- `400`: The request is malformed or a field failed validation. Codes: validation_error, invalid_idempotency_key, invalid_cursor, plan_not_purchasable, stripe_signature_invalid, support_upload_rejected, sign_in_check_required.
- `401`: No usable credential was sent. Codes: missing_api_key, session_required, mfa_required.
- `403`: The credential may not do this, or the account or key is stopped. Codes: sending_domain_blocked, young_domain_held, domain_sending_disabled, domain_not_verified, onboarding_recipient_not_a_member, onboarding_sender_unavailable, account_suspended, account_sandboxed, human_action_required, csrf_origin_rejected, charge_not_this_account, invalid_api_key, restricted_api_key, insufficient_role, invite_email_mismatch, domain_scope_violation, dedicated_ip_assigned_by_us, approval_required, staff_review_required, trust_paused, kill_switch_active.
- `409`: The request conflicts with the current state. Codes: domain_already_exists, template_name_taken, template_alias_taken, template_in_use, segment_in_use, contact_resubscribe_required, email_still_scheduled, domain_verified_elsewhere, domain_not_claimable, return_path_subdomain_in_use, overage_not_on_plan, term_not_on_sale, subscription_active, portal_change_unavailable, already_in_account, idempotency_in_flight, idempotency_payload_mismatch, approval_expired, support_closed, support_reopen_expired, support_merge_conflict, support_reply_too_soon.
- `413`: The request body is larger than this operation accepts. Codes: payload_too_large, support_upload_too_large.
- `415`: The request body is not JSON. Codes: unsupported_media_type.
- `429`: A rate, quota or ramp ceiling was reached. Codes: onboarding_daily_cap_reached, trust_throttled, invite_limit_reached, rate_ceiling_exceeded, daily_quota_exceeded, monthly_quota_exceeded, rate_limit_exceeded, support_rate_limited.
- `500`: Something failed on our side. Codes: internal_server_error.

---

[API](https://skmtc.dev/agentisend/apis/agentisend-api.md) · [All operations](https://skmtc.dev/agentisend/apis/agentisend-api/llms.txt) · [OpenAPI document](https://skmtc.dev/agentisend/apis/agentisend-api/revisions/3066dda62a56?raw)