Private email infrastructure · Operating since 2011

Deliverable SMTP infrastructure for senders who cannot afford to be filtered.

Northbound designs, provisions and operates dedicated email systems for high-volume marketers, affiliate networks, iGaming and crypto operators, transactional platforms and agencies. Every deployment is engineered around the sender — not sold from a catalogue. We do not publish pricing and we do not accept every prospective client.

Talk to an engineer Infrastructure overview

Current capabilities

MTA software	PowerMTA · Postfix · OpenSMTPD
IPv4 pools	US · UK · NL · DE · CH · SG
Peak sustained throughput	24M messages/day per node
Authentication	SPF · DKIM · DMARC · BIMI
Feedback	Google Postmaster · SNDS · JMRP · SBRS · Yahoo CFL
Support	Engineer-on-call, 24/7 for retained clients
Contract model	Monthly retainer, no per-message markups

Capabilities are indicative. Individual deployments are scoped in the proposal.

Trusted by private clients across

European iGaming operators · US affiliate networks · Regulated crypto exchanges · FX brokers · Enterprise SaaS platforms · Global e-commerce brands · Performance media agencies · Managed service resellers · Direct-response lead generation

Our infrastructure

Operated in-house. No third-party ESPs behind the label.

Dedicated SMTP

Private MTA clusters allocated per client, with tuned VMTAs, bounce classification and full log access.

PowerMTA & Postfix

Licensed PowerMTA where the sending profile demands it; hardened Postfix for API-driven and transactional flows.

Dedicated IPs

IPv4 in six regions, allocated per brand or per stream. Reverse DNS, SWIP and rotation configured per plan.

Domain management

Sending domain provisioning, SPF flattening, DKIM key rotation, DMARC alignment and BIMI submission.

Bounce & FBL processing

Full bounce classification, complaint suppression and feedback loop integration across major providers.

SMTP APIs

REST and SMTP submission with per-stream credentials, envelope shaping and per-message tagging.

Why senders retain us

Engineer-led, not sales-led

You speak to the engineer who will run your infrastructure — from the first call through steady-state operations.

Custom by default

Every deployment is designed around the sending profile. There are no plans, tiers, or self-service dashboards to work around.

Selective client roster

We decline projects that would harm the reputation of the other clients on our platform. This is a policy, not marketing.

Deliverability accountability

Inbox placement is measured, reported and owned by us — not delegated to a monitoring vendor.

Independent

Northbound is privately owned and unbranded. Clients that need it stay unattributed.

Continuity

The engineers who onboard you are the same engineers on call three years later. Low headcount, long tenure.

Industries we operate for

Vertical-specific infrastructure and deliverability strategy.

All industries →

iGaming Affiliate marketing Crypto & Web3 Forex & CFD Lead generation E-commerce Performance agencies SaaS & transactional Enterprise Email marketing cos.SMTP resellers

How we work

01
Scoping call
A 30–45 minute technical conversation. Volumes, verticals, current infrastructure, list hygiene, complaint history. We ask hard questions on the first call because a proposal that avoids them is useless.
02
Deliverability audit
Current SPF/DKIM/DMARC, sending IP posture, Postmaster and SNDS position, bounce and complaint history. Delivered as a written report.
03
Infrastructure design
MTA choice, IP topology, warm-up curve, domain and subdomain plan, feedback loop routing, monitoring.
04
Provisioning & warm-up
New IPs and domains are warmed to volume on schedules calibrated to the vertical and content profile.
05
Steady-state operations
Ongoing reputation management, seed testing, complaint remediation, incident response, monthly review.

Technology stack

A short, opinionated selection. We do not chase new dependencies.

MTA

PowerMTA 6.x, Postfix 3.x, OpenSMTPD

Authentication

OpenDKIM, OpenDMARC, SPF flattening, ARC

Feedback

Google Postmaster Tools, Microsoft SNDS, JMRP, Yahoo CFL

Monitoring

In-house telemetry, seed testing, blocklist watches

Provisioning

SaltStack, Terraform, immutable image pipelines

Networking

Multi-region IPv4, anycast MX, DDoS-scrubbed transit

Data plane

Postgres for state, ClickHouse for logs, S3-compatible archives

Security

Hardened Linux, key-only SSH, MFA, per-client segmentation

Frequently asked

See the full FAQ →

Do you publish pricing?

No. Every project is scoped individually. Volume, vertical, current infrastructure, deliverability position and required support level all affect the proposal. Reach out and we will send a quote within one working day.

Do you take on any client?

No. We evaluate every prospective client. If a project falls outside our operating policy — for example, deceptive content, unlawful lists, or an unrealistic deliverability expectation — we decline. This protects the reputation of every other client on our platform.

What senders do you work with?

High-volume marketers, affiliate networks, iGaming, crypto and forex operators, lead generation companies, transactional SaaS platforms, e-commerce brands, agencies, and other SMTP resellers that need a serious upstream.

How long does onboarding take?

Standard onboarding for dedicated SMTP with a small IP block typically completes in three to five working days. Larger deployments with warm-up plans, multiple domains and Google Postmaster reviews take two to three weeks.

Do you provide dedicated IPs?

Yes. Dedicated IPv4 in multiple regions, allocated per client, with rDNS, SPF alignment and rotation policies configured to the sending profile.

Do you run PowerMTA?

Yes. We operate licensed PowerMTA nodes for clients that require its throughput, VMTA control and bounce classification. Postfix and OpenSMTPD are also available for clients whose needs are better served by them.