Newsletter + Cold Outreach · BYO SMTP or SES
One platform for
every email you send.
MailerSpark handles the boring and the bold: drag-and-drop newsletter campaigns, multi-step cold outreach sequences, a unified reply inbox with AI classification, automations, and a full REST API. Pay SES rates, not SaaS rates.
Free forever on 500 contacts · No credit card · 3-minute setup
Built for teams shipping email at every scale
Two products, one platform
Newsletters and cold outreach,
not one or the other.
Most platforms do one. Some do the other. MailerSpark does both, on the same contacts, the same brand, the same API.
Newsletter
- Drag-and-drop campaigns with A/B subjects
- Send windows, time zones, daily caps
- Automations from subscribed / added triggers
- Double opt-in, public forms, JSON API
- Open / click / revenue tracking per send
Cold Outreach
- Multi-step sequences with wait days
- Gmail, 365, or any SMTP/IMAP inbox
- Inbox rotation, warmup, stop on reply
- Residential proxy rotation (SOCKS/HTTP)
- Unibox with AI reply classification
By the numbers
Built so you can scale without surprises
MailerSpark sits between you and your SMTP provider. The product is the intelligence; the transport is yours.
Newsletter
Send campaigns that
make you money.
Drag-and-drop builder, A/B subject lines, send windows, double opt-in, automations, and revenue tracking — all on the contacts and segments you already have.
- Drag-and-drop email builder11 block types, merge tags like {{firstName}}, and table-based HTML that renders in every client.
- A/B subject testingTest subject lines and pick the winner before the rest of your list sees a weaker opener.
- Send windows and daily capsStay in your subscribers' time zone and throttle volume to protect deliverability.
- Public subscribe + double opt-inDrop-in forms, JSON API for signups, and a built-in double opt-in flow for compliance.
Cold Outreach
Multi-step sequences,
without the chaos.
Connect Gmail, Microsoft 365, or any SMTP/IMAP inbox. Build sequences with wait days and conditional steps, rotate through inboxes, and reply from a single unified inbox.
- Inbox rotation & warmupPriority or round-robin across connected mailboxes, with automatic warmup ramps so new domains don't get throttled.
- Residential proxy rotationRotate the SMTP egress IP per send via SOCKS4/5, HTTP, or HTTPS proxies to keep deliverability high.
- Provider matchingAuto-pick the inbox whose sending domain best matches each recipient's domain.
- Stop on replyWhen a prospect replies, the sequence stops automatically — no double-sending, no awkward follow-ups.
Unibox
Every reply,
in one place.
The Unibox syncs replies from every connected inbox every 60 seconds. AI classifies them as Interested, Not Interested, Out of Office, Wrong Person, or Auto-Reply — so your team only sees what matters.
- Gmail, Microsoft 365, IMAPNative OAuth for Gmail and Microsoft Graph for 365, plus a generic IMAP connector for any provider.
- AI reply classificationBring your own OpenAI key, point at a local Ollama model, or use the heuristic fallback. No vendor lock-in.
- Per-thread contextSee the full conversation, the original sequence step, and the contact record — without leaving the inbox.
Built-in CRM
Contacts, segments, and
suppressions that stay in sync.
Every email — newsletter or cold — flows through the same contacts, custom fields, and suppression list. Duplicate merges, CSV import, double opt-in, and a rule-based segment builder.
- Rule-based segmentsall / any logic across any contact field, with live previews of who matches.
- Custom fieldsPer-organization text fields that show up everywhere — forms, merge tags, automations, the API.
- Auto-suppressionsBounces, complaints, and unsubscribes are honored across every campaign automatically.
For developers
A real REST API,
not a Zapier apology.
Bearer-token auth, idempotent endpoints for contacts and lists, full campaign creation with sequence steps, and 20 outbound webhook events — all documented and versioned at /api/v1.
- API keys with scopesGenerate, revoke, and hash-lookup keys from the dashboard. The full secret is only ever shown once.
- Signed webhooksHMAC-SHA256 signatures, automatic retries, a delivery log, and SSRF-guarded endpoint URLs.
- Rate limits you can seeBacked by Redis with per-key visibility in the dashboard — no mystery 429s.
curl -X POST https://app.mailerspark.com/api/v1/campaigns \
-H "Authorization: Bearer ms_live_***" \
-H "Content-Type: application/json" \
-d '{
"type": "cold",
"name": "Q1 Outbound",
"listId": "lst_8a3f",
"steps": [
{ "waitDays": 0, "subject": "Quick question" },
{ "waitDays": 3, "subject": "Re: Quick question" }
]
}'The full feature suite
Everything you need. One bill.
No "Email Marketing Pro" add-on. No "Cold Outreach Enterprise" upsell. If it's in MailerSpark, it's in your plan.
Newsletter Campaigns
Broadcasts, A/B subjects, send windows, double opt-in, and revenue tracking.
Learn moreCold Outreach
Sequences across Gmail, 365, or SMTP. Inbox rotation, warmup, stop on reply.
Learn moreUnibox
Every reply in one thread, with AI classification across all connected inboxes.
Learn moreEmail Builder
Drag-and-drop with 11 block types and table-based HTML that renders everywhere.
Learn moreAutomations (Beta)
Visual workflows: subscribe triggers, delays, sends, and conditions.
Learn moreTemplates
Marketing, transactional, and cold templates — duplicate, edit, reuse.
Learn moreContacts & CRM
Custom fields, CSV import, merge tools, public subscribe, and double opt-in.
Learn moreSegments
Rule-based dynamic filters with live previews — all / any match logic.
Learn moreConnected Inboxes
Gmail OAuth, Microsoft 365 OAuth, or any SMTP/IMAP mailbox. Encrypted at rest.
Learn moreAI Reply Classification
OpenAI, Ollama, or heuristic. Categorize replies as Interested, OOO, and more.
Learn moreProxy Rotation
SOCKS4/5, HTTP, HTTPS — rotate SMTP egress IPs to keep deliverability high.
Learn moreWebhooks
20 event types, HMAC-signed, with delivery log and automatic retries.
Learn moreSave 10× on email costs
Stop overpaying the SaaS tax.
Most email platforms charge $50–$300 a month for 10K contacts — and then charge you again per email. With MailerSpark + your own Amazon SES account, you pay SES rates for the email itself. We charge for the product. That's it.
- ~$0.10 per 1,000 emails via SES direct
- Unlimited contacts on every paid plan
- Bring any SMTP provider — not just SES
- No per-seat charges for your team
Integrations
Plays nice with what you already have
SMTP providers, OAuth inboxes, webhooks, and a REST API. Wire MailerSpark into your stack in an afternoon.
Pricing that scales with you
Start free. Grow into it.
500 contacts and 1,000 emails a month on the free plan, forever. Upgrade when you need more volume, sequences, or team members.
Free
Get started with core sending
- 500 contacts
- 1,000 emails / mo
- 1 team member
- • SMTP + Amazon SES
- • Drag-and-drop builder
- • Contact CRM
Starter
For growing newsletters
- 5,000 contacts
- 15,000 emails / mo
- 3 members
- • Automations
- • A/B testing
- • API access
Growth
For cold + newsletter at scale
- 25,000 contacts
- 75,000 emails / mo
- 5 members
- • Cold outreach sequences
- • Unibox + AI classify
- • Webhooks + Brands
Business
High volume teams
- 100,000 contacts
- 300,000 emails / mo
- 10 members
- • Priority support
- • SLA
- • Audit log
Enterprise
Unlimited scale
- Unlimited contacts
- Unlimited emails / mo
- Unlimited
- • Custom SLA
- • Dedicated CSM
- • Volume pricing
What teams say
Trusted by teams that actually send
Newsletter + cold outreach in one tool means my team stops fighting five logins. The Unibox alone replaced our $90/mo reply tool.
Paying SES rates instead of SaaS rates is the entire reason we switched. The builder is faster than what we were using, too.
The API and webhooks let us wire MailerSpark straight into our onboarding flow. Sequences trigger from product events.