ARC-Relay Features — What's under the hood.

01Forwarding

Every alias on your domain, one inbox.

Catch-all by default. Per-alias by choice. Nothing gets lost — even mail to addresses you've never made.

FIG.01 — RELAY TOPOLOGY

TLS · DKIM · DMARC · SPF

02AI Auto-Reply

Auto-replies that actually know your product.

Each domain gets its own knowledge base — markdown files, FAQs, policies — and a persona you define. The assistant retrieves what's relevant and replies. Credit-capped, so a runaway thread can't run up the bill.

Jordan Mehta

[email protected]

09:14

Quick question — does the free plan include DKIM signing, or do I need to upgrade?

◇ AUTO-REPLY · KB-GROUNDED

Hi Jordan,

DKIM signing kicks in on the Pro plan and above — outbound forwards get signed automatically. The free tier still gets full SPF + DMARC pass-through, just no DKIM signature on the relay.

Best,

◇ SENT · sourced from KB arc-relay-support · 1 credit

2.1

Knowledge base

Drop markdown into the domain's KB folder — vector-indexed and retrieved per query

2.2

Persona per domain

A custom system prompt sets voice, rules, and what the assistant won't say

2.3

Auto-appended footer

Your support address and signature attached to every reply

2.4

Prompt-injection guard

Ignores instructions hidden in inbound mail trying to override the persona

2.5

Credit cap

Hard monthly limit per plan. Bot stops drafting when you hit it — costs never surprise you.

03Block rules

Catch-all by default, blocks where you draw the line.

Catch-all forwarding picks up mail to any address on your domain — even ones you've never made. Per-alias overrides redirect specific addresses elsewhere. Sender block rules drop unwanted senders by email or domain pattern before they reach you.

◇ curl · block a sender

BASH

curl -X POST https://api.arc-relay.com/v1/sender-rules \
  -H "Authorization: Bearer $ARC_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "sender_pattern": "@spammer.example",
    "action": "block"
  }'

04Email auth

Authentication that survives the relay.

Most forwarders break SPF/DMARC the moment they relay. We seal the message with ARC, rewrite the envelope with SRS, and sign outbound with DKIM (Pro+) — so the receiving server can still verify the original sender.

◇ SPF

Original sender's SPF preserved through SRS rewriting

◇ DKIM

Outbound forwards signed with your relay key (Pro+)

◇ DMARC

Alignment preserved end-to-end via ARC sealing

◇ ARC

Authenticated Received Chain seals the auth result at each hop

◇ SRS

Sender Rewriting Scheme keeps the bounce path valid

◇ TLS

Encrypted transport to your destination mail server

05API & webhooks

Every UI action is a REST call.

If you can do it in the dashboard, you can script it. Webhooks fire on receive, forward, reply-drafted, reply-sent, and bounce events.

◇ curl · create alias

BASH

curl -X POST https://api.arc-relay.com/v1/aliases \
  -H "Authorization: Bearer $ARC_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "domain": "you.dev",
    "local": "support",
    "destination": "[email protected]",
    "auto_reply": true
  }'

What's under the hood.

Every alias on your domain, one inbox.

Auto-replies that actually know your product.

Catch-all by default, blocks where you draw the line.

Authentication that survives the relay.

Every UI action is a REST call.

Ready to set it up?

What's
under the hood.