What Is APRF? The New Email Deliverability Feedback Standard Explained

Current Status: APRF is an active IETF proposed draft, but senders can actually receive live daily reports today. Comcast (Xfinity) is actively sending production beta reports to senders who publish an APRF DNS record. Other co-authoring providers (like Google) have not yet enabled generation.

For as long as organizations have sent bulk email, deliverability managers have faced a fundamental blind spot: once a mailbox provider accepts a message, nobody can say with certainty where it actually landed. Senders have historically pieced together an estimated picture of inbox placement using artificial seedlist testing or by checking disparate postmaster dashboards across Google, Microsoft, and Yahoo. Each provider offers different metrics in incompatible formats, leaving senders without a single, unified source of truth.

A new proposed specification aims to solve this long-standing industry problem. Known as APRF (Aggregate Performance Reporting Format), this emerging protocol allows mailbox providers to generate standardized daily reports on message placement and recipient engagement, sending them directly to senders. Rather than relying on seedlist estimates, senders can now see how their authenticated mail streams were classified and how real recipients interacted with them.

Here is an in-depth breakdown of what APRF is, how its discovery mechanism works, how it compares to existing standards like DMARC, and how you can publish your first DNS record to start collecting reports today.

What Is APRF (Aggregate Performance Reporting Format)?

Aggregate Performance Reporting Format (APRF) is a proposed email reporting protocol designed to provide senders with structured, machine-readable feedback on email deliverability and user interaction. While traditional protocols report on authentication or connection failures at the gateway, APRF focuses entirely on what happens to messages after they are accepted by the receiving server.

The specification is currently defined in the IETF Internet-Draft titled draft-brotman-aggregate-performance-reporting-00. Published on March 17, 2026, with an intended status on the Standards Track, the document was co-authored by three email industry veterans:

• Alex Brotman (Comcast)
• Tom Corbett (Iterable)
• Emil Gustafsson (Google)

According to the official IETF Datatracker status page, the initial -00 revision carries an official expiration date of September 18, 2026. As an individual submission, APRF is still in its earliest evaluation phase (“I-D Exists”) and has not yet been formally adopted by an IETF Working Group or issued as an RFC. However, co-authorship by a leading ISP, a major enterprise ESP, and Google makes APRF one of the most significant deliverability initiatives proposed in recent years.

Note on Terminology: Outside of email technology, the acronym “APRF” frequently appears in medical and biological research to represent Advanced Platelet-Rich Fibrin or Acute-Phase Response Factor. In the context of email security, infrastructure, and email deliverability, APRF refers exclusively to the Aggregate Performance Reporting Format specification.

APRF vs. DMARC Reports vs. Feedback Loops: What Is Actually Different?

To understand where APRF fits into an enterprise email strategy, it is helpful to contrast it with existing reporting mechanisms across four key dimensions: scope, data format, identity key, and delivery method.

Authentication vs. Performance: The Core Distinction

The primary distinction between DMARC aggregate reports and APRF comes down to authentication versus performance:

1. DMARC is about authentication. DMARC aggregate reports answer the question: “Did this email authenticate properly via SPF and DKIM using my visible domain name, and was an unauthorized source attempting to spoof my brand?”
2. APRF is about performance. APRF reports answer the question: “Now that the email passed authentication and was accepted, where did the mailbox provider place it, and how did recipients interact with it?”

APRF does not replace DMARC aggregate reports or traditional complaint feedback loops. Instead, it serves as a complementary layer. DMARC secures your brand identity against impersonation, while APRF provides visibility into how mailbox algorithms evaluate your sender reputation.

Furthermore, APRF differs from provider dashboards such as Google Postmaster Tools. Dashboards require manual logins or custom API integrations tailored to a single provider. APRF establishes an open, vendor-neutral standard that delivers performance metrics straight to your inbox in a structured JSON payload.

What is Inside an APRF Report?

APRF reports are generated once per day by participating mailbox providers. Each report covers a complete 24-hour UTC window (from 00:00:00 UTC to 23:59:59 UTC). The report is sent as an email attachment formatted in JSON, using either application/json or compressed application/gzip.

The JSON payload is divided into two distinct sections: the Header and the Body.

1. Header Metadata

The header contains administrative details about the reporting period, the provider issuing the report, and the sender’s DKIM identity:

• version: The APRF specification version (currently 1).
• source: The name or identifier of the reporting mailbox provider (for example, Comcast).
• dkim_domain: The DKIM domain (d=) verified in the outgoing signature.
• dkim_selector: The specific DKIM selector (s=) matched by the provider.
• report_start / report_end: Unix epoch timestamps defining the exact 24-hour UTC coverage window.
• contact_info: An administrative email address or URL provided by the reporting entity.
• sdi_used: Indicates whether Signer-Defined Identifiers were parsed for sub-stream segmentation.

2. Metric Families (The Report Body)

The body contains aggregate counts organized into two core metric families:

Classification Metrics (Placement)

Classification metrics track where the receiving provider routed accepted messages:

• inbox: Messages delivered to the primary inbox folder.
• unwanted: Messages routed to spam, junk, or bulk folders.
• promotional: Messages categorized into secondary promotional tabs or folders.
• forwarded: Messages automatically redirected by recipient mailbox rules.

Engagement Metrics (User Behavior)

Engagement metrics aggregate real recipient actions taken after delivery:

• Positive: Favorable user actions, including opens, link clicks, moving messages out of the spam folder (rescue actions), or marking messages as important.
• Negative: Unfavorable user actions, such as clicking “Report Spam”, deleting messages without reading, or unsubscribing.
• Neutral: Non-evaluative movements, such as archiving, filing into custom folders, or manual forwarding.

3. Signer-Defined Identifiers (SDI) for Granular Tracking

By default, APRF reports aggregate data at the DKIM selector level. However, large enterprises often send multiple email types under a single DKIM selector. To address this, the draft includes an optional feature known as Signer-Defined Identifiers (SDI).

By declaring an sdi tag in your DNS record, you can instruct mailbox providers to inspect a specific custom header (such as X-Campaign-ID or Signer-Info) that has been included in your DKIM signature. The provider will then break down the daily classification and engagement metrics by those sub-identifiers, supporting up to four nested levels of segmentation. This allows organizations to evaluate transactional notifications separately from marketing campaigns while maintaining a streamlined DKIM key architecture.

Annotated Example of an APRF JSON Payload

Below is an illustrative JSON report structured according to the draft-brotman-aggregate-performance-reporting-00 specification:

[
  {
    "header": {
      "version": 1,
      "source": "Comcast/Xfinity",
      "dkim_domain": "example.com",
      "dkim_selector": "s1024",
      "report_start": 1773705600,
      "report_end": 1773791999,
      "contact_info": "[email protected]",
      "sdi_used": "none",
      "extra_info": "https://postmaster.comcast.net/aprf-info"
    },
    "body": [
      {
        "classification": {
          "inbox": 45000,
          "unwanted": 120,
          "promotional": 0,
          "forwarded": 15
        },
        "engagement": {
          "positive": 14200,
          "negative": 18,
          "neutral": 850
        }
      }
    ]
  }
]

How APRF Works: From DNS Discovery to Report Delivery

APRF utilizes a DNS-based discovery flow modeled on established protocols like DMARC and TLS-RPT. Because reporting is tied directly to message signing, a mailbox provider can discover your reporting preferences without requiring custom portal configurations.

The Step-by-Step Flow

1. Email Transmission: Your infrastructure sends outgoing emails signed with valid DKIM signatures.
2. Signature Inspection: The receiving provider accepts the email, verifies the DKIM signature, and extracts the domain (d=example.com) and selector (s=s1024). DNS Query: The provider queries DNS for a TXT record located at: s1024._aprf._domainkey.example.com
3. Record Parsing: The provider parses the TXT record to verify the mandatory v=APRFv1 tag and retrieve the destination email address defined in the rua tag.
4. Aggregation and Delivery: Over the next 24 hours, the provider aggregates placement and engagement data for that selector. At the end of the UTC day, it generates the JSON report and sends it to the specified rua address via SMTP.

Privacy Safeguards and Volume Thresholds

To protect individual user privacy, the APRF draft explicitly recommends that mailbox providers enforce volume suppression thresholds. If a sender transmits only a handful of messages to a provider on a given day, raw performance metrics could allow the sender to deduce the actions of specific individuals.

Under the APRF privacy framework, providers suppress reporting entirely or apply noise-addition bucketing algorithms for low-volume streams. If your daily message volume to a specific mailbox provider falls below their privacy threshold, you will not receive a report for that day.

How to Start Collecting APRF Reports Today

Even though APRF is still an active IETF draft rather than a finalized RFC standard, Comcast (Xfinity) is actively generating live, daily APRF reports in production (in beta) for senders who publish the DNS TXT record.

Publishing an APRF record takes only a few minutes and requires no software installation or changes to your email infrastructure. Follow these four steps to start receiving reports.

Step 1: Identify Your Active DKIM Selector

Inspect the email headers of a recent outgoing message from your domain. Locate the DKIM-Signature header and note the selector (s=) and domain (d=).

For example, if your header displays d=example.com and s=s1024, your APRF record will be hosted at: s1024._aprf._domainkey.example.com

Wildcard Support: If you manage dozens of selectors and want to avoid creating individual records for each one, the specification allows you to publish a catch-all record using an asterisk (*): *._aprf._domainkey.example.com

Receiving providers will check for a specific selector record first. If none exists, they will fall back to the wildcard record.

Step 2: Establish a Dedicated Reporting Mailbox

Create a dedicated mailbox or email alias to collect incoming reports (for example, [email protected]). Because reports contain automated JSON files, sending them to a dedicated alias prevents your primary inbox from being flooded with daily attachments.

Step 3: Publish the DNS TXT Record

Log in to your DNS management console and add a new TXT record with the following parameters:

• Host / Name: s1024._aprf._domainkey.example.com (or *._aprf._domainkey.example.com for a wildcard)
• Record Type: TXT
• TTL: 3600 seconds (1 hour)
• Value: v=APRFv1; rua=mailto:[email protected];

If you want to enable sub-stream tracking via Signer-Defined Identifiers for a header named X-Campaign-ID with a carat (^) delimiter, construct your value as follows:

v=APRFv1; rua=mailto:[email protected]; sdi=X-Campaign-ID,^;

Step 4: Verify Publication

Use a DNS lookup tool or command-line utility (dig or nslookup) to confirm that your new record resolves publicly:

dig TXT s1024._aprf._domainkey.example.com +short

Realistic Current Expectations

It is important to set realistic operational expectations when deploying an APRF record:

• Active Beta Status: Comcast (Xfinity) is currently the only major mailbox provider actively generating production APRF reports in beta.
• Google’s Role: Google co-authored the draft, signaling strong long-term interest in standardized performance reporting. However, Gmail does not currently generate APRF reports. Senders should continue referencing Gmail Email Sender Guidelines for current Gmail requirements.
• Zero Cost to Publish: Publishing an APRF record today costs nothing and incurs no performance overhead. Once published, your domain will automatically begin receiving reports from Comcast, as well as from any additional providers that adopt the standard in the future.

Why APRF Matters (and What It Will Not Fix)

Industry reaction to APRF has been largely positive. In an analysis on Spam Resource, deliverability expert Al Iverson praised APRF for delivering “real, aggregate data driven by actual user behavior” rather than artificial seedlist estimates. Iverson highlighted APRF as a complementary tool that works alongside existing platforms to provide clearer operational visibility.

The Key Benefits

7. Real Recipient Data: Seedlists rely on artificial accounts that lack realistic engagement histories. APRF reflects real delivery outcomes across actual user accounts.

8. Standardized Open Format: Senders can ingest JSON metrics from multiple providers into a single internal analytics pipeline, eliminating the need to build custom web scrapers or API connectors for different postmaster portals.

9. Sub-Stream Granularity: Using the SDI tag allows engineering teams to isolate deliverability issues affecting specific transactional message types without splitting their main DKIM key architecture.

Known Limitations

Despite its advantages, APRF has clear boundaries:

• Limited Provider Support Today: With only Comcast generating reports in beta, APRF does not yet provide global deliverability visibility.
• No Diagnostic Root-Cause Data: An APRF report indicates that a percentage of messages landed in the spam folder, but it does not specify why. It will not tell you whether an issue was caused by poor IP reputation, URL blocklisting, or spam filter content triggers.
• Evolving Draft Specification: As an active IETF draft, tag syntax and JSON schema fields remain subject to revision before final standardization.

Authentication Remains the Prerequisite

APRF metrics are computed only after a receiving server accepts an email. If your outgoing messages fail basic authentication checks, receiving servers may block them at the gateway, rendering placement reporting irrelevant.

Before chasing deliverability feedback, ensure your primary authentication controls are properly configured:

• Set up valid DKIM records across all legitimate sending sources.
• Verify that your domain is protected by DMARC with aligned SPF and DKIM signatures.
• Use a centralized DMARC Report Analyzer to monitor authentication health and progress toward an enforcement policy (p=reject).

Should You Publish an APRF Record Now?

Yes, for high-volume senders. If your organization sends significant email volume to consumer addresses at Comcast/Xfinity, publishing an APRF record provides immediate value. You will gain access to real daily placement data and establish an automated reporting pipeline before other major providers join the standard.

For low-volume or purely B2B senders, publishing an APRF record is optional but recommended. While privacy thresholds mean you may not receive daily reports immediately, publishing a wildcard TXT record (*._aprf._domainkey.example.com) takes less than five minutes, carries zero security risk, and ensures your domain is ready as broader industry adoption develops.

Frequently Asked Questions

What does APRF stand for in email?

APRF stands for Aggregate Performance Reporting Format. It is a proposed open standard designed to deliver standardized daily performance and recipient engagement data from mailbox providers back to email senders.

Is APRF an official IETF standard yet?

No. APRF is currently an active individual Internet-Draft (draft-brotman-aggregate-performance-reporting-00). It has not yet been formally adopted by an IETF Working Group or published as an RFC standard.

How is APRF different from DMARC aggregate reports?

DMARC aggregate reports (RUA) measure email authentication alignment (SPF and DKIM validation) relative to the visible From domain. APRF measures post-acceptance performance (inbox placement and user engagement) relative to the DKIM signing domain and selector.

Which mailbox providers support APRF today?

Comcast (Xfinity) is currently the only mailbox provider sending beta APRF reports in production. Although Google co-authored the specification, Gmail does not currently support APRF generation.

Do I need DKIM to receive APRF reports?

Yes. APRF discovery records are published under the DKIM domain key namespace (_domainkey), and reporting is tied directly to the DKIM selector used to sign outgoing messages.

Does APRF replace traditional Feedback Loops (FBLs)?

No. Traditional feedback loops send near real-time ARF reports when an individual user marks a message as spam. APRF provides daily aggregated metrics summarizing overall placement and user engagement across your entire mail stream.

Next Steps: Verify Your Domain Foundation

APRF provides valuable insight into message placement, but it depends entirely on a healthy email infrastructure. If your authentication records are misconfigured or unaligned, mailbox providers will reject your messages before placement metrics can be recorded.

To ensure your domain is ready for APRF:

• Confirm that all outgoing mail streams are signed with valid, aligned DKIM keys.
• Review your DMARC policy using the PowerDMARC Domain Analyzer to verify authentication alignment.
• Publish a catch-all APRF record (*._aprf._domainkey.yourdomain.com) to begin receiving performance feedback as participating providers come online.

• About
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Yunes Tarada

Domain & Email Security Expert at PowerDMARC

Yunes is an Operations Team Lead at PowerDMARC with expert knowledge in email authentication and security. Yunes is a Microsoft-certified Azure Administrator Associate with certifications in CompTIA A+ and many more.

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