Your providers, behind one endpoint.
Connect the accounts you already have and order the chain. A rejected key or an empty credit balance becomes a reroute instead of a missing mail.
Most failures that stop transactional mail are about the provider account, not the message: a key someone rotated, a credit balance that ran out, an account paused for review. None of them is fixed by sending the same mail to the same account again, so Mailway sends it to the next account instead, and the mail arrives while you repair the first. The one refusal it never walks the chain for is a bad recipient address, because that address is bad at every provider.
Which provider goes first is the project's routing strategy, and changing it is a console setting, not a deploy. Free-first is the strategy that changes a bill: it sends through providers with free allowance left first, and the calculator below shows the effect at your volume. Every supported provider can sit in the chain (provider guides).
Providers fail.
Your app shouldn't notice.
Your app hands off once, gets 250 OK, and moves on. Mailway reads whatever the provider says back: a rejected key, an empty credit balance, a rate limit. Then it retries on the next provider in your chain five seconds later; a provider it has already tried waits on a widening backoff. Here's a bad day, handled with no one stepping in:
Failover needs at least two providers in a project. It is included on Pro and up, with up to 3 providers per project on Pro.
illustration · a failover chain of three · each retry to an untried provider leaves 5 s after the last failure
Four routing strategies
Primary provider first. When an attempt fails, the next provider in your chain takes it five seconds later; one this message already tried waits on a widening backoff (1, 5, 15, 30 min).
Providers with free allowance left go first. Paid volume mostly starts once the free capacity you entered is used up (an approximate count, not a hard cap), and exhausted providers stay available for failover.
Take providers in turn, one message after another. Spreads spend and sender reputation, and keeps any one account further from its rate limits.
A random provider per message, the default for a new project. Retries draw again, so for a guaranteed failover order pick Fallback.
Not all errors are equal
A permanent reject on a single-recipient send stops there instead of walking your chain. Addresses your providers report as bounced or complained go on your suppression list, and suppressed addresses are skipped before any provider sees them again. Everything else fails over, and every attempt is on the message's timeline.
Drag the slider.
Watch the savings.
The free-first routing strategy sends through providers with free allowance left first, and paid volume mostly starts once the free capacity you entered is used up (Mailway counts it approximately, so treat it as a target, not a hard cap). You pay providers directly at their prices; Mailway takes no margin on delivery, because the provider bill never passes through us.
vendor free tiers as published, 2026 Q3 · ses at its à la carte rate · you pay providers directly · mailway never marks up provider cost
7 providers in one project: Business and up
Your mailer config has
one block to change
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