help/content/reference/checkers/happydeliver.en.md

date	author	title	description	weight
2026-06-11T09:00:00+02:00	nemunaire	Outbound deliverability (happyDeliver)	Send a real test message from your domain to a happyDeliver instance and grade how well it would be delivered to a real inbox.	210

The Outbound deliverability checker (named Outbound deliverability (via happyDeliver) in happyDomain) measures how a message sent from your domain would actually fare on its way to a recipient's inbox. Rather than inspecting DNS records in isolation, it drives an external happyDeliver instance to perform an end-to-end test.

This checker is service-level: it is attached to a service (typically the mail configuration of a subdomain) and needs SMTP credentials to send the test message on your behalf.

How it works

For each run, the checker:

1. Allocates a fresh recipient address on the configured happyDeliver instance.
2. Sends a real test email from the tested domain to that address, using the SMTP submission server and credentials you provide.
3. Polls happyDeliver until the message has been received and analysed.
4. Stores happyDeliver's report and exposes one score per section as a metric.

happyDeliver grades the message across several sections (DNS, authentication, spam filters, blacklists, headers, content) and computes an overall score. The checker turns each section into a rule.

{{% notice style="info" title="An external happyDeliver instance is required" %}} This checker does nothing on its own: it needs a reachable happyDeliver instance, identified by its API URL and bearer token. Those are usually configured once by the administrator and can be overridden per domain. {{% /notice %}}

What it checks

Each section rule compares happyDeliver's score for that section against a configurable minimum. The check is Critical when the score falls below the minimum, otherwise OK.

Rule	What it verifies	Default minimum
happydeliver.score.overall	happyDeliver's Overall score	70
happydeliver.score.dns	DNS configuration score	70
happydeliver.score.authentication	Authentication score (SPF / DKIM / DMARC)	80
happydeliver.score.spam	Spam-filter score	70
happydeliver.score.blacklist	Blacklist score	90
happydeliver.score.header	Header score	70
happydeliver.score.content	Content score	60

A separate happydeliver.lifecycle rule reports the outcome of the run itself: OK when the message was analysed, Critical when the test address could not be allocated, the message could not be sent, or happyDeliver returned a wait/fetch/parse error, and Warning when the message was not analysed before the timeout elapsed.

Each section minimum can be tuned through its own min_score_<section> rule option in the happyDomain interface.

Options

Sending (per domain)

Option	Meaning	Default
Sending SMTP host (smtp_host)	Hostname or IP of the submission server used to send the test email. Required.	(none)
Sending SMTP port (smtp_port)	Submission port (587 for STARTTLS, 465 for implicit TLS, 25 for plain).	587
SMTP username (smtp_username)	Username for the submission server (omit for anonymous submission).	(none)
SMTP password (smtp_password)	Password for the submission server.	(none)
TLS mode (smtp_tls)	How to negotiate TLS: starttls, tls, or none.	starttls
From address (from_address)	Address used in the From header; must belong to the tested domain.	no-reply@<domain>

Message content (per domain)

Option	Meaning	Default
Subject (subject_override)	Override the default test subject.	(built-in)
Plain-text body (body_text_override)	Override the default plain-text body.	(built-in)
HTML body (body_html_override)	Override the default HTML body.	(built-in)

Timing (per domain)

Option	Meaning	Default
Wait timeout (wait_timeout)	Seconds to wait for happyDeliver to receive and analyse the message.	900
Poll interval (poll_interval)	Seconds between status polls (clamped to the 2–60 range).	5

Instance (admin, overridable per domain)

Option	Meaning	Default
happyDeliver instance URL (happydeliver_url)	Base URL of the happyDeliver API.	(admin)
happyDeliver API token (happydeliver_token)	Bearer token for the happyDeliver API.	(admin)

In happyDomain

Enable this checker from the service's Checks tab and provide the SMTP submission details so happyDomain can send the test message. See {{< relref "/pages/checks" >}} for the general workflow of scheduling and reading checks.

Because deliverability depends heavily on your anti-spoofing posture, pair this checker with a well-configured {{< relref "/reference/services/email" >}} setup (SPF, DKIM and DMARC). For the DNSSEC half of your domain's trust chain, see {{< relref "/reference/checkers/dnssec" >}}.