Introduction

The ACE SEND API lets your systems — a CRM, a game platform, a payment backend — send WhatsApp and SMS messages through ACE SEND, follow their delivery and keep the contacts of your account up to date.

Everything you do in the API belongs to your account in the console: the balance that pays for messages, the templates your team created, the contacts and the stop lists.

What you can do

Task	How
Send a WhatsApp or SMS message	POST /v1/messages with a template of your account
Send a one-time code or an own SMS text	POST /v1/messages with channel: "sms" and text — when your account allows own texts
Know what happened to a message	webhooks, or GET /v1/messages/{id}
Find messages by your own id, number or status	GET /v1/messages
See which templates you can send	GET /v1/templates
Keep contacts and their fields in sync for campaigns	POST /v1/contacts

Campaigns, template editing and moderation, contact imports, reports and billing stay in the console.

The basics

• Base URL: https://api.ace-send.com/v1. HTTPS only.
• Authentication: every request carries an API key: Authorization: Bearer ak_live_…. See Authentication.
• Test and live: a test key (ak_test_…) sends through a free sandbox that never reaches a phone. Build and test your integration with it, then switch the key.
• JSON: send Content-Type: application/json; answers are JSON. Errors are application/problem+json with a stable machine-readable code — see Errors.
• Asynchronous delivery: POST /v1/messages answers 202 Accepted once the message is queued. Its statuses come later, as webhooks.

Conventions

What	Format	Example
Phone numbers	E.164: +, country code, number — no spaces or dashes	+5521998120937
Ids	a type prefix and a random part; treat them as opaque strings up to 64 characters	msg_CgdWeHQN4sPaZnXfh7kP5
Timestamps	ISO 8601 in UTC, seconds precision	2026-11-02T12:00:04+00:00
Money	an object with a decimal string (6 digits after the point) and an ISO 4217 currency	{"amount": "0.062500", "currency": "USD"}
Countries	ISO 3166-1 alpha-2	BR
Template languages	as in the template: en, pt, pt_BR…	pt

Id prefixes: msg_ message, cnt_ contact, cmp_ campaign, whd_ webhook delivery, whe_ webhook address.

Languages of texts. Error titles, field messages and failure texts follow the Accept-Language header: English (default), Portuguese, Spanish, Turkish or Russian. Codes never change with the language — build your logic on codes, show titles to people. Webhooks are always in English.

Compatibility. Within v1 we add things without notice: new fields in answers and webhook bodies, new endpoints, new optional request fields, new webhook events, error codes, failure codes and enum values. Ignore what you do not know rather than failing on it. Removing or renaming a field, or changing its meaning, would be a new version. See the changelog.

Machine-readable spec

The whole API is described in OpenAPI 3.1, examples and webhooks included: https://docs.ace-send.com/openapi.json. Import it into Postman, Insomnia or a client generator.