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Apollo Signal publishes public SDKs from the same API contract. Each SDK defaults to https://api.signal.apollodeploy.com and exposes the same email, contact, domain, metrics, suppression, and webhook operations.
Use SDKs only in trusted server, worker, or command-line environments. Never include a Signal API key in browser JavaScript, a mobile binary, or a public repository.

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Before you install

  1. Create an API key with Emails: Send permission.
  2. Add and verify a sending domain.
  3. Store the key as SIGNAL_API_KEY in your server-side secret manager.

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JavaScript and TypeScript

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Languages and frameworks

PHP and Laravel intentionally use one Composer package. Laravel discovers the bundled service provider automatically; plain PHP applications load only the core SDK.

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Public source and downloads

All SDK source, checksummed release archives, and generation provenance are public in Apollo-Deploy/signal-sdks. The Signal API implementation remains private. The command-line package is also available as @apollo-deploy/signal-cli:

SDK examples

Copy production send examples for every published SDK, including HTML, metadata, idempotency, and test mode.

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After the API accepts a message

A successful send returns an ID for the accepted message. Acceptance is not final delivery. Open Emails to follow the timeline, or configure signed webhooks for asynchronous delivery, bounce, complaint, rejection, and suppression outcomes.

REST API

Call the public HTTP API without an SDK.

SMTP

Send through a standard SMTP client.