Customer.io
The value is the network, the data or the infrastructure. Keep paying.
Behavioural messaging: campaigns triggered by what someone does in your product, across email, push, SMS and in-app, with segmentation over the whole event history.
Build the narrow version: a handful of triggered emails, not a journey engine. BE CLEAR ABOUT SCOPE - Live segmentation over millions of profiles is the product. Do not attempt it - Five or six triggered emails is a weekend and covers most of the value early on STACK - Postgres, a worker, Resend or SES PROFILES AND EVENTS - One profile per user with JSON properties - An append-only events table; nothing is ever updated TRIGGERS - A trigger is: event name, an optional property filter, a delay, and a template - A cancellation condition — send the abandoned-cart mail unless a purchase event arrived first FREQUENCY AND QUIET HOURS - No more than N marketing messages per profile per week - Never send between 22:00 and 08:00 in the profile time zone; hold until morning SEGMENTS, COMPUTED LATE - A segment is a saved SQL predicate evaluated when needed, not a maintained membership table Include the schema, the worker and a README on the frequency and quiet-hours rules.
What you lose
- Live segments recomputed as events arrive, which is a streaming problem rather than a cron job
- Multi-channel delivery — email, push, SMS and in-app — with one set of frequency rules across all of them
- Journey branching with waits, goals and holdout groups, and the reporting to tell whether any of it worked
- Deliverability at volume on dedicated IPs, warmed and monitored
If you would rather not build
- Loops, for a smaller version of the same idea
The escape hatch
open source · no votes, no paid placement
Novu
$0Notification infrastructure across email, push, SMS and in-app, self-hostable.
novuhq/novufree · open source
Listmonk
$0Self-hosted campaigns with an API to trigger sends from your app.
knadh/listmonkfree · open source
Why this verdict
our own opinion · changed only by a person
32/100
Verdict no at 32. A few triggered emails are easy; live segmentation, multi-channel and dedicated-IP deliverability are infrastructure you would be rebuilding badly.
History
tracked since 10 Aug 2026 · nothing is ever overwritten
Nothing recorded yet. This chart fills in once the page has visitors, votes or prompt copies — it will not draw a flat line to look busy.
Questions about Customer.io
answered from the record above
Is Customer.io free?
No — the plan we track is $100 a month. Essentials from around $100/month billed monthly for 5,000 profiles, rising with profile count.
Can you replace Customer.io by building your own?
KEEP IT. The value is the network, the data or the infrastructure. Keep paying. Replacement score 32 out of 100, build time longer than it saves. Read what you lose before you decide.
How much does Customer.io cost?
$100 a month on Essentials — $1,200 a year. Recorded 9 Aug 2026.
What do you lose by replacing Customer.io?
Live segments recomputed as events arrive, which is a streaming problem rather than a cron job; Multi-channel delivery — email, push, SMS and in-app — with one set of frequency rules across all of them; Journey branching with waits, goals and holdout groups, and the reporting to tell whether any of it worked; Deliverability at volume on dedicated IPs, warmed and monitored. If any of those carry weight for you, keep paying.
Is there an open-source alternative to Customer.io?
Yes: Novu, Listmonk. The prompt on this page is for when you want it your way instead.
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