Woodpecker Inbox Ninja has blind spots. Fill them for free.

Woodpecker was one of the first cold-outreach platforms to bundle a real deliverability testing tool — Inbox Ninja — inside the product. It is a genuinely good feature. It is also narrower than most users realise, and the gaps matter if your audience is outside the US Gmail/Outlook majority.

What Inbox Ninja covers

Inbox Ninja is Woodpecker's built-in placement test. It typically sends to a small seed pool of:

• Gmail (personal).
• Google Workspace.
• Outlook.com (consumer).
• Microsoft 365.
• Yahoo.

That is five providers. For a US-focused campaign targeting mid-market and SMB, it covers most of the real-world recipient base. For anyone else, it leaves gaps.

What it misses

The providers Inbox Ninja does not (or does not consistently) cover:

• ProtonMail — privacy-conscious users, technical buyers, some regulated industries.
• iCloud / me.com — prosumer and Apple-heavy B2C. Notorious for aggressive filtering.
• Mail.ru, Yandex, Rambler — the dominant CIS providers. If you sell into Russia, Belarus, Kazakhstan, these are 60%+ of your audience.
• GMX, web.de, T-Online — German consumer and SMB.
• Orange, La Poste, Free.fr — French ISP-provided mailboxes.
• Fastmail, Zoho, Hey — smaller but growing providers with distinct filtering behaviour.

When these gaps matter

The gaps matter in direct proportion to your audience distribution. Three rough scenarios:

• US SaaS SMB outreach: Inbox Ninja alone is probably fine. Gmail + Microsoft 365 + Yahoo = 85%+ of your real recipients.
• European B2B: you need GMX, Orange, La Poste, Free.fr at minimum. Inbox Ninja misses all four. Placement there can be drastically different from Gmail.
• CIS or Russia-adjacent: Mail.ru and Yandex are mandatory. Inbox Ninja shows nothing here. You are flying blind on the majority of your list.

A pre-sequence checklist

Before launching any new Woodpecker sequence, run this checklist. It takes under 15 minutes.

1. Auth: send one test email from the Woodpecker-connected mailbox to a Gmail seed. Open full headers. Confirm SPF, DKIM and DMARC all show pass.
2. Tracking domain: verify your custom Woodpecker tracking domain against Spamhaus DBL and URIBL. Replace if listed.
3. Placement (Inbox Ninja): run Woodpecker's built-in test. Note the numbers.
4. Placement (external, 20+ providers): run the free inbox-check test from the same mailbox on the same template. Compare against Inbox Ninja results.
5. Content score: SpamAssassin score under 3.0, Rspamd positive. Over 5.0 means rewrite before send.
6. Link audit: every URL in the template scanned for reputation. No bit.ly or tinyurl.

Running the free 20+ provider test

The workflow:

1. Open inbox-check and request a new test. Get a list of seed addresses covering 20+ providers.
2. Create a mini-sequence in Woodpecker with a single step, content identical to your real sequence's first email.
3. Import the seed addresses as prospects in that sequence.
4. Run the sequence once. Each seed receives the email from your real Woodpecker-connected mailbox.
5. Back in inbox-check, watch the live placement report populate. You get per-provider Inbox/Spam/Promotions breakdown, plus auth and DNSBL status.

Total time: about 10 minutes. No account required on the placement tool.

Integrating into Woodpecker workflow

A healthy rhythm for most Woodpecker teams:

• Before every new sequence launch: full 20+ provider placement test.
• Weekly: quick test on the currently active sequence's first email.
• After any domain / DNS change: immediate retest.
• After adding a new sending mailbox: individual test before including it in rotation.

Keep a simple spreadsheet: date, sequence name, Inbox % at Gmail, Outlook, Mail.ru, GMX. Week-over-week deltas reveal problems long before Woodpecker's reply rate does.

GlockApps + Woodpecker combined

Some teams layer GlockApps on top of Inbox Ninja. It is worth it if:

• You send across 5+ sending mailboxes and need scheduled automated tests.
• You want Postmaster Tools history integrated with placement history in one view.
• You report deliverability up to a team or client and need polished dashboards.

It is not worth it if you are a solo SDR or a small team running a handful of sequences. The free inbox-check tool covers the per-provider placement question at no cost. Use it alongside Inbox Ninja for the gap coverage.

Frequently asked questions