Plain English campaigns
Type a brief. Get a campaign back. Specify audience, tone, goal, things to avoid. Iterate by editing the brief, not by hunting through nested template menus.
We didn't build "AI Mailchimp." We built the email backend product teams actually need: composable, observable, fast to deploy, honest about deliverability.
Type a brief. Get a campaign back. Specify audience, tone, goal, things to avoid. Iterate by editing the brief, not by hunting through nested template menus.
Each recipient's email is rewritten at queue time. Subject line, hero, CTA, sign-off — all calibrated to their actual engagement signal in the past 90 days.
We predict the 15-minute window each recipient is most likely to open. No more "send at 10am Tuesday." Harbor sends to each contact when they're in their inbox.
A/B/n on subject lines, preheaders, hero copy, CTA placement. Bayesian winners chosen automatically — no need to wait for "significance" math.
Trigger sends from any event in your stack: Segment, Rudderstack, custom webhook, Postgres CDC. Latency from event → send is sub-second on Crew, sub-200ms on Fleet.
Every subject is scored against a deliverability + open-rate model before send. Catches phantom-spam triggers (excess punctuation, ALL CAPS, banned phrases) and rewrites them.
HubSpot, Salesforce, Attio, custom Postgres. Your contact data is the source of truth. Harbor reads it, never duplicates it, writes back engagement events.
Every send is a trace. Deliverability per-domain, per-template. Open and click events with full causal lineage. Plug Harbor into Datadog, Honeycomb, Grafana — no custom pipeline.
Node, Python, Go, Rust, Elixir, Ruby. Typed payloads, retries with exponential backoff, idempotency keys. Open-source, MIT licensed.
Automatic IP/domain warmup for new senders. Starts at 50/day, ramps to 100k/day over 4 weeks. Pauses if reputation drops. No spreadsheet calendars.
Every action — campaign edit, send, list change, model fine-tune — is logged immutably. Streamable to your SIEM. SOC 2 auditors love it.
One global suppression list across all your accounts. List-Unsubscribe header set correctly. Mailto + one-click HTTPS unsubscribe — both honored. No dark patterns.
You can hit the production API in under 2 minutes. Send your first transactional email in 5. Set up a behavioral campaign in 15.
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