---
title: "Estimate a single send's eligibility, segments, and cost without sending"
method: POST
path: "/v2/messages/preflight"
tags: ["preflight-v2"]
---

# Estimate a single send's eligibility, segments, and cost without sending

`POST /v2/messages/preflight`

## Request

- Base URL: `https://api.tracklysms.com/api`
- URL: `https://api.tracklysms.com/api/v2/messages/preflight`
- Auth: API key in header `X-Api-Key`

## Request body

- PreflightRequest
  - `body` string: Required SMS body or optional MMS caption, at most 4096 characters
  - `list_number` string, required: Sending list number (E.164)
  - `media` MMSMedia[]: Nonempty MMS attachments array; media and subject metadata may total at most 512 KiB
    - `content_id` string: Optional unique ASCII attachment content identifier
    - `content_type` string: Optional MIME type
    - `url` string, required: Public HTTPS media URL
  - `subject` string: Optional MMS subject; requires media
  - `to` string, required: Recipient (E.164)

## Response `200`

Success

---

[API](https://skmtc.dev/tracklysms/apis/trackly-sms-api.md) · [All operations](https://skmtc.dev/tracklysms/apis/trackly-sms-api/llms.txt) · [OpenAPI document](https://skmtc.dev/tracklysms/apis/trackly-sms-api/revisions/ac1ad22cb2a9?raw)