Build a custom email automation system — lifecycle emails that aren't limited by your ESP.
Klaviyo, Customer.io, and Drip are excellent email automation platforms. But they're limited by your ability to send them data. A custom email automation system is directly connected to your application's event stream — triggered by exactly the right user actions.
SaaS founder or marketing operator who needs email automation triggered by specific application events, with custom logic that ESP visual builders can't express
Email automation platforms require sending behavioral data to a third party. Klaviyo, Customer.io, and HubSpot all work by receiving events (user.signed_up, feature.used, trial.ended) via API or JavaScript SDK.
The limitation is: the events these platforms can use are limited to what you send them. Complex internal state — a combination of user attributes, usage patterns, and time-based conditions — is difficult to express in their visual builders.
When custom email automation makes sense:
- Trigger conditions combine multiple application states that are complex to send to an ESP
- Compliance restrictions prevent sending user data to third-party platforms
- Scale makes per-email pricing of ESPs expensive
- Complete control over template rendering and delivery timing is required
Custom email automation does not replace ESP deliverability infrastructure — it uses Resend, Postmark, or SendGrid for actual delivery. The custom system handles: trigger logic, sequence management, template rendering, and delivery scheduling.
Email automation system deployed — event-triggered sequences, user segmentation, template management, and delivery analytics
Event listener
application events trigger automation rules
Sequence manager
multi-step email sequences with timing
Condition logic
send/skip/branch based on user state
Template engine
React Email templates with personalization
Delivery integration
Resend or Postmark for actual delivery
Analytics
send, open, click, unsubscribe rates per sequence
One honest number to start.
Fixed-scope, fixed-price. The number below is the starting point — final scope is built from your brief.
Email automation system deployed — event-triggered sequences, user segmentation, template management, and delivery analytics
Three steps, every time.
The same repeatable engagement on every project. No surprises, no mystery, no billable ambiguity.
Brief & discovery.
We send you questions, then get on a call. Output: a written scope with every step, feature, and integration listed.
Build & ship.
Fixed schedule, weekly reviews. No scope creep unless you change the scope — and if you do, we reprice it transparently.
Warranty & retainer.
30-day warranty on every launch. Most clients stay on a monthly retainer for ongoing features and maintenance.
Why Fixed-Price Matters Here
Email automation systems have defined trigger and sequence patterns. Fixed-price from the spec.
Related engagements.
Questions, answered.
Yes. Subject line variants with split testing. Winning variant determined after 24h open rate. Remainder of sends use the winning variant.
Either. Replace: custom system handles all lifecycle email. Integrate: custom system handles complex triggered emails, Klaviyo handles broadcast campaigns. Spec defines the boundary.
Tell Ryel about your project.
Describe what you’re building and what outcome you need. You’ll have a written, fixed-price scope within the week.