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Comparison · Mkt Auto
Customer.io vs Sulu
A side-by-side editorial comparison of Customer.io and Sulu — release velocity, themes, recent moves, and the top alternatives to consider.
Customer.io vs Sulu: at a glance
What is Customer.io?
Customer.io spent the summer pushing messaging off the screen and into location, time, and the lock screen
The summer release cycle put more than ten features into the product, and the coherent ones are about context rather than content: geofences trigger workflows when someone enters or leaves a physical location, live notifications render as iOS Live Activities and Android Live Updates, date triggers now read attributes on custom objects, and a notification inbox retains pushes. Around that sits infrastructure work — SMS via Sinch, Infobip and Vonage, multiple mobile apps per platform in one workspace, send-rate controls on automations — and an LLM actions surface where knowledge sources can be attached once and reused across prompts. The most recent entry is editor ergonomics in Design Studio.
What is Sulu?
Sulu ships 2.6 and 3.0 in lockstep, and the 3.0 line still reads like a maintenance branch.
Sulu is a Symfony-based CMS for developer-built sites, and its release process is a synchronised pair: every 3.0.x patch ships within a minute of the matching 2.6.x patch, carrying largely the same pull requests. Six releases in five months — 3.0.8/2.6.25, 3.0.7/2.6.24, 3.0.6/2.6.23 — are almost entirely fixes, editor upgrades and framework compatibility work. A security advisory was patched across both branches in March.
Customer.io vs Sulu: editorial side-by-side
Customer.io
7.5MKT AUTO
Customer.io spent the summer pushing messaging off the screen and into location, time, and the lock screen
◆ Current state
The summer release cycle put more than ten features into the product, and the coherent ones are about context rather than content: geofences trigger workflows when someone enters or leaves a physical location, live notifications render as iOS Live Activities and Android Live Updates, date triggers now read attributes on custom objects, and a notification inbox retains pushes. Around that sits infrastructure work — SMS via Sinch, Infobip and Vonage, multiple mobile apps per platform in one workspace, send-rate controls on automations — and an LLM actions surface where knowledge sources can be attached once and reused across prompts. The most recent entry is editor ergonomics in Design Studio.
◆ Where it's heading
The platform is expanding the set of things that can start a message and the set of places one can land, which is a different axis from the segmentation-and-copy tooling most of this category competes on. Geofences and live notifications both take work that previously required a specialist vendor or custom device code and make it a workflow primitive. The LLM actions work is following the same instinct — reusable knowledge sources are the beginning of prompt infrastructure rather than a prompt box — but it is the least developed of the threads. Meanwhile send-rate control and multi-app support read as enterprise deployment blockers being cleared.
◆ Prediction
Expect the location and live notification surfaces to gain the operational controls that continuous device features require, and the LLM actions path to keep accreting reusable pieces. Design Studio is receiving steady editor polish, so a broader component authoring release is plausible.
Sulu
5.0MKT AUTO
Sulu ships 2.6 and 3.0 in lockstep, and the 3.0 line still reads like a maintenance branch.
◆ Current state
Sulu is a Symfony-based CMS for developer-built sites, and its release process is a synchronised pair: every 3.0.x patch ships within a minute of the matching 2.6.x patch, carrying largely the same pull requests. Six releases in five months — 3.0.8/2.6.25, 3.0.7/2.6.24, 3.0.6/2.6.23 — are almost entirely fixes, editor upgrades and framework compatibility work. A security advisory was patched across both branches in March.
◆ Where it's heading
Three threads run through the pairs. Editor upkeep is constant, with CKEditor moving to 47 LTS and then 48 and the fallout — table widgets, webpack font builds — fixed release by release. Framework compatibility is the second: Request->get calls replaced for Symfony 8, PHPUnit 13 and PHPStan kept green on lowest dependencies. The third and most interesting is data-model cleanup on the 3.0 side, where tags migrated from names to IDs behind a newly added DoctrineMigrationsBundle, with smart-content filters reworked to match. What is not visible is any capability that exists on 3.0 and not on 2.6 — a major version that is not yet behaving like one.
◆ Prediction
Expect the paired-release rhythm to continue with more Symfony 8 preparation and CKEditor 48 fallout. The open question is when 3.0 starts receiving work that is not upmerged from 2.6; until then the major version number is not buying users anything.
Alternatives to Customer.io and Sulu
Other Mkt Auto products tracked by Sparkpulse, ranked by recent ship velocity. Each card links to a full editorial trajectory and lets you pivot into a head-to-head comparison with either Customer.io or Sulu.
GetResponse
Ecommerce blocks keep landing while open tracking gets a regulatory escape hatch
Buttondown
Buttondown documents its events API, opening dashboard analytics to anyone who wants to pull them
Gumloop
The reporting layer arrives, and it counts what agents did and what they cost.
Customer.io
The AI agent moves into Slack, so operating Customer.io no longer means opening it.
n8n
Four release lines in parallel, and nearly every patch lands on the agent builder.
See all Customer.io alternatives → · See all Sulu alternatives →
Recent activity from Customer.io and Sulu
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 6d agoCustomer.ioDesign Studio: new and improved canvas editing experience
- 14d agoCustomer.ioControl how fast your automations send messages
- 21d agoCustomer.ioGeofences: message people when they enter or exit a location ⚡
- 21d agoCustomer.ioSet up SMS with Sinch, Infobip, or Vonage
- 21d agoCustomer.ioAdd reusable knowledge sources to LLM actions
- 21d agoCustomer.ioCustomer.io’s Summer Release: Meet your customers where they are
- 1mo agoSuluSulu 3.0.8 validates selection filter params at build time
- 1mo agoSuluSulu 2.6.25 adds a redirect after SSO login
- 2mo agoSuluSulu 3.0.7 fixes smart-content filtering and speeds up indexing
- 2mo agoSuluSulu 2.6.24 upgrades CKEditor to version 48
- 3mo agoSuluSulu 3.0.6 migrates tag names to IDs with Doctrine migrations
- 3mo agoSuluSulu 2.6.23 moves to CKEditor 47 LTS and preps Symfony 8
Frequently asked questions
What is the difference between Customer.io and Sulu?
They serve adjacent needs but don't currently overlap on shipped themes. Customer.io is currently shipping more aggressively (velocity 7.5 vs 5.0), with 1 editorial sparks in the last 30 days against 0. See the at-a-glance table above for a side-by-side breakdown of velocity, recent sparks, and editorial themes.
Is Customer.io better than Sulu?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. Customer.io is currently shipping more aggressively (velocity 7.5 vs 5.0), with 1 editorial sparks in the last 30 days against 0. For your specific use case, the alternatives sections above list other Mkt Auto products to evaluate alongside.
What are the best alternatives to Customer.io?
Top Customer.io alternatives in Mkt Auto are ranked by recent ship velocity. Browse the "Customer.io alternatives" section above for the current picks, or visit /alternatives/customerio for the full list with editorial commentary on each.
What are the best alternatives to Sulu?
Top Sulu alternatives in Mkt Auto are ranked by recent ship velocity. Browse the "Sulu alternatives" section above for the current picks, or visit /alternatives/sulu for the full list with editorial commentary on each.