Bulko
Features

Everything you need for effective campaigns

Bulko brings together everything that usually needs to be manually pieced together: SMTP rotation, AI content variability, IMAP response collection with classification, trigger-based follow-ups, and analytics. No subscriptions.

Platform in review

Every feature is built for one goal — to increase the share of emails that land in the inbox and bring a reply.

Deliverability 01

Ready-made sending infrastructure.

Campaign Platform does not require you to connect SMTP yourself: Bulko selects an available account from the managed pool and controls its limits. Custom SMTP is available only for selected special accounts.

Each account gets an individual rate limit (by default 20 emails/day for Gmail, up to 50K for SES). When the limit is reached, rotation automatically switches to the next valid SMTP.

If the SMTP provider returns an authentication error (535) or a temporary failure (421/450), the account is excluded from rotation and the campaign continues through the remaining ones. You get a notification about the problematic SMTP in the dashboard.

22+
step-by-step SMTP guides.
1100+
SMTP accounts in active rotation
Support
  • Gmail / Workspace
  • Outlook / Office 365
  • Amazon SES
  • SendGrid / Brevo / Mailgun
  • Yandex / Mail.ru / Yahoo
  • Zoho / FastMail / GMX
  • Any standard SMTP
Variability layer
  1. 1 Спинтакс {Привет|Здравствуйте} — мгновенно
  2. 2 Merge-теги {{name}} — из списка
  3. 3 AI-rewrite — каждые N писем тема и тело генерируются заново
  4. 4 Random subject — кнопка для генерации новой темы по контексту
Content 02

AI makes every email slightly different

The main reason cold campaigns end up in spam is that filters recognize the template. When 1,000 identical emails go out from a single template, providers see the pattern and send them all to spam at once.

Bulko obfuscates templates with four layers: spintax, merge tags, AI-rewrite of subject and body every N emails, and dynamic randomization of sentence order. As a result, no two emails are identical.

Use your OpenAI API key or Bulko's built-in AI credits (Gemini 2.5 Flash). You define the basic prompt — for example, 'selling a Python course for beginners, friendly tone'. The AI generates variations within this description.

Replies 03

AI sorts your incoming replies for you

When your outreach goes through 10 SMTP accounts, replies come to 10 different mailboxes. Bulko connects via IMAP to each SMTP and collects all replies into one shared inbox.

Then the AI classifier takes over. Each email is labeled into 5 categories: positive (interested), negative (refusal), question (needs details), bounce (address unavailable), auto-reply (vacation/out of office). A confidence score from 0 to 1 shows how confident the AI is.

In the «Replies» section, you only see what's important. By default, bounce messages are hidden, leaving positive and questions. Each reply immediately shows the campaign, sender, and AI analysis.

positive · 0.94
«Yes, I'd love to learn more, can we hop on a call next week?»
question · 0.81
«How is your tool different from Mailchimp?»
auto_reply · 0.97
«I'm out of office until 24th of May.»
Follow-up 04

The second email is sent only to those who have shown interest

The first email is cold, without links or sales CTAs, with one goal: to get a response. If a positive response is received, Bulko automatically sends a follow-up with detailed information, a link to a demo, or a calendar after N hours.

Links and sales content are allowed in follow-ups: only those who have already shown interest receive them. This is not cold outreach, but a warm response to a request.

Parameters: delay from 1 hour to 1 week, minimum AI confidence (default 0.7), automatic or manual sending after your confirmation. If the recipient replies again before the follow-up, sending is canceled.

Cycle
  1. 1 Cold email goes out, without links or CTAs
  2. 2 IMAP fetches the reply → AI classifier → positive
  3. 3 After N hours, a follow-up with all the details is sent
  4. 4 Stop-on-reply: a repeat reply stops further follow-ups
Analytics 05

See the funnel, not just "sent"

Funnel

Sent → Delivered → Opened → Clicked → Replied. With absolute numbers and percentages at each step.

Trends

Daily charts for 14 days. See which day of the week gets the best open rate and when deliverability drops.

Breakdown

By SMTP — which account shows the best open rate. By subjects — which subjects get more opens and clicks.

Integrations 06

REST API for your own systems.

Launch campaigns from your own script or a universal HTTP action in Zapier/n8n. Upload recipients, read statistics, replies, and balance via the Bearer API.

Outbound webhooks are not yet available in production and will be added after the REST API is stabilized.

POST /api/v1/campaigns/launch
Authorization: Bearer YOUR_TOKEN
Content-Type: application/json

{
  "name": "Q2 Outreach",
  "subject": "{Hi|Hello} {{name}}",
  "body": "...",
  "recipients": ["[email protected]", "[email protected]"],
  "smtp_pool": "warmed-eu"
}
Deliverability 07

Continuous infrastructure self-checks

Bulko provides built-in validators. Before launching a campaign, you can check if SPF/DKIM/DMARC are configured correctly, if the domain is on blacklists, and if MX servers are responding.

AI Content Filter — built in

Every outgoing message — both from campaigns and via SMTP relay — is automatically scanned by a hybrid filter (heuristics + Gemini AI) for phishing, malware, brand impersonation, and scams. Suspicious content is blocked before sending and saved as a snapshot.

This keeps the IP pool's reputation high — so deliverability stays stable. Marketing, transactional, and cold outreach all go through without a hitch.

Ready to launch a campaign?

500 email credits and 50 AI credits to start — no card required. Pay-as-you-go after that: from $0.50 per 1000 emails.