API overview

Base URL, content type, and the shape of every response.

The ZevSend API is a REST API. All requests and responses are JSON, all endpoints are versioned, and all errors share a single shape so you can write one error handler for the whole surface.

Base URL

https://api.zevsend.com

There is no separate sandbox host. Test-mode API keys (sk_test_…) route to the same endpoints; the key implies the mode.

Versioning

The API is versioned by URL prefix. The current version is v1:

POST https://api.zevsend.com/v1/emails
POST https://api.zevsend.com/v1/sms
POST https://api.zevsend.com/v1/whatsapp

Backwards-incompatible changes ship under a new prefix (v2). Existing prefixes keep working — we’ll give you at least 12 months’ notice before sunsetting one.

Authentication

Pass your API key as a Bearer token in the Authorization header. See Authentication for details.

curl https://api.zevsend.com/v1/emails \
  -H "Authorization: Bearer sk_test_..."

Content type

Every request must set Content-Type: application/json. Every response is JSON. Empty responses still set Content-Type: application/json for parser symmetry.

Response shape

Success

Successful POST endpoints return 202 Accepted with the identifier of the resource that was created:

{
  "id": "eml_01HXYZ...",
  "to": "you@example.com",
  "status": "sending",
  "sandbox": true,
  "created_at": "2025-05-24T12:34:56.789Z"
}

202 rather than 201 because the send is asynchronous — by the time you read this, the message is on its way but hasn’t necessarily been accepted by the upstream network yet.

Error

Every error response is shaped the same way. See Errors.

{
  "error": {
    "code": "invalid_phone",
    "message": "Recipient must be a phone number in international format, e.g. +2348012345678.",
    "param": "to",
    "type": "validation_error",
    "request_id": "req_01HXYZ..."
  }
}

Identifiers

Every resource has a stable, opaque public id with a type prefix:

Ids are stable for the lifetime of the resource and safe to store in your own database.

Timestamps

All timestamps are ISO 8601 in UTC, to millisecond precision:

2025-05-24T12:34:56.789Z

Pagination

List endpoints (delivered through the GraphQL surface that powers the dashboard) use cursor-based pagination via the before parameter. The REST send endpoints are write-only, so they don’t paginate.

Updated at, Thursday, October 1, 2026