Connect InboxKit Mailboxes to BrandJet in 90 Seconds

BrandJet is one of only three sequencers in the entire InboxKit catalog that uses API-key-only authentication, the other two are SendKit and Supersend. Everything else uses email + password. That matters because the connect screen for BrandJet looks different: a single API Key field, no email, no password, and a debounced validation that calls BrandJet's verify endpoint after 800 milliseconds of typing idle.

You paste the key, InboxKit validates it, and a green badge appears showing your BrandJet account name and email. Click Connect Account and every selected InboxKit mailbox flows into BrandJet as a new sender. Total time: about 90 seconds. This is the integration to pick if you are running brand-intelligence outreach and want AI Unibox sentiment tracking on every reply.

When you paste a BrandJet API key into the InboxKit Connect screen, the flow is:

The reason for the debounce is UX: pasting a long key character-by-character would trigger dozens of validation calls without it. The 800ms wait means BrandJet's API gets exactly one verify call per paste operation, even if you type the key instead of pasting it.

What the green card shows you. After a successful validation, the connect screen renders Connected as {account.email} plus a small card with the account's full name and email address. This is your confirmation that you are about to push mailboxes into the correct BrandJet account. If the name on the card does not match who you think you are connecting to, stop and check, you may have pasted a key for a different BrandJet account.

Gather these items before opening the InboxKit Sequencers Connect screen:

On finding the BrandJet API key. API keys live in Settings → API Keys inside BrandJet. Generate a new key rather than reusing one you already shared with another tool, that way revoking it later doesn't break other integrations. Keys are long (usually 40+ characters) and prefixed with something like bj_ so you can tell them apart from other sequencer keys. For a comparative look at how cold email tools authenticate, see cold email sequencer integration guide.

The full click path from InboxKit dashboard:

Total: about 90 seconds.

Note that the Connect Account button stays disabled until the API key is validated, you cannot bypass the check. If you see the button disabled and the green card not showing, the validation is still pending or the key is invalid. Wait 2 seconds, then check for the red 'Invalid API Key' badge.

AI Unibox is BrandJet's differentiator. Every reply to a mailbox connected via the InboxKit integration lands inside Unibox, and BrandJet classifies each reply automatically:

BrandJet's AI triages these so you can focus on the positives and objections, not the out-of-offices. This is similar to what ReachInbox's Onebox does for AI classification, but BrandJet layers in brand-sentiment on top, it tracks whether the brand-mention sentiment across all your outreach is trending positive or negative over time. For high-volume outreach where you cannot hand-read every reply, this is the main reason to pick BrandJet over a standard unified-inbox tool.

How it works with InboxKit. InboxKit does not touch the reply classification, that is 100% on the BrandJet side. InboxKit's job ends when the mailbox is successfully provisioned in BrandJet. From there, BrandJet pulls replies via IMAP (standard flow) and runs them through its classifier.

Set these inside BrandJet once the import completes:

BrandJet does not ship a first-party warmup product, so pair it with either the InboxKit isolated warmup add-on ($3/mailbox/month) or a dedicated warmup tool like TrulyInbox or Warmy. Pick one: running two warmup engines on the same mailbox generates inconsistent signals at Gmail Postmaster. For a side-by-side of the major warmup options, see the email warmup tools comparison.

The specific error badges InboxKit will surface during a BrandJet connect, and what to do:

On API key rotation. BrandJet API keys do not expire automatically, but you should rotate them every 6 months as security hygiene. When you rotate, the existing InboxKit connection will keep syncing until the next export attempt, then fail with 'Invalid API Key'. Fix: edit the connection in InboxKit → Sequencers → BrandJet → paste the new key. The existing mailboxes inside BrandJet are not affected.

Four smoke tests:

Test 1: account card matches expectations. Before clicking Connect Account, confirm the BrandJet account name and email on the green card match who you think you're connecting to. If they don't match, stop.

Test 2: mailbox appears in BrandJet. After the connect completes, log into BrandJet and open Senders. Confirm every InboxKit mailbox you selected is listed. If one is missing, the export hit BrandJet's per-call rate limit: retry that mailbox alone from InboxKit → Exports → Retry.

Test 3: send test. From BrandJet, send a test email to your own address. Confirm delivery in <30 seconds with DKIM passing in headers.

Test 4: reply triage. Reply to the test with 'yes I'm interested'. Within 2 minutes, BrandJet's AI Unibox should classify it as 'Positive'. If the classification is missing, the sentiment feature may be gated behind your BrandJet plan tier. Check BrandJet → Plan Features.