Route sending by quotas, not hope.
Mailers.io aggregates your connected providers and distributes outbound traffic according to per-hour and per-day limits you control. Deterministic, rule-based routing across your entire provider stack.
- Bring your own providers
- BYOPBring your own providers
- Per-provider caps
- HourlyPer-provider caps
- Not random
- Rule-basedNot random
- Every decision logged
- ObservableEvery decision logged
Mailers.io does not bypass provider policy. Routing respects each provider's terms and sending limits.
Single-provider sending is one incident away from downtime.
When every outbound email depends on one provider, you inherit their outages, quota cliffs, policy changes, and reputation events.
Concentration risk
A single provider failure takes every campaign, automation, and transactional send with it. Your outbound stops until they recover.
Quota cliffs
Provider daily and hourly caps are fixed. Hit them in a single workspace and the rest of your sending queues or fails until the window resets.
Reputation spillover
Mixing cold, transactional, and marketing on one provider lets a reputation event on one stream damage the others.
One send request, deterministic provider selection.
Every outbound message evaluates your rules in order: priority, quota availability, scope. A provider is selected — or the message waits — based on what the rules allow.
- Domain scope: marketing.example.com
- Workspace: Outbound ops
- Priority class: campaign
- Amazon SES · marketing80k/day62% of window usedeligible
- SendGrid · cold pool50k/day94% of window usedthrottle
- Mailgun · transactional120k/day31% of window usedeligible
- Custom SMTP · failover20k/day7% of window usedeligible
The controls you get out of the box.
Per-hour & per-day quotas
Set sending caps for every connected provider. Mailers.io respects them automatically without human babysitting.
- Rolling windows
- Multiple quotas per provider
- Automatic reset
Priority pools
Group providers into priority tiers. Higher-priority pools drain first; lower pools absorb overflow or act as failover.
- Weighted priority
- Tiered failover
- Isolated traffic classes
Scoped rules
Route by domain, list, workspace, or campaign. Keep transactional away from cold, marketing away from notifications.
- Domain-level routing
- Workspace isolation
- Campaign overrides
Compliance-aware
Routing runs alongside suppression and DNC checks, so a routed message is also a compliant message.
- Global suppression
- Per-workspace DNC
- Bounce-aware routing
Observable decisions
Every routed message records which provider was selected and why. Replay any send to understand the decision.
- Full send log
- Rule attribution
- Provider event trail
Controlled capacity
Add providers to scale out. Retire providers without code changes. Routing rules adapt automatically.
- Add/remove providers live
- Gradual rollout
- Capacity planning
What engineers actually ask.
Concrete answers on how routing decisions are made.
Stop betting outbound on a single provider.
Connect the providers you already use, define your rules, and let Mailers.io split sending by what each provider can actually absorb.
- Quota-aware
- Rule-based
- No random switching