Cheap means different things here
Teams usually land on this comparison while trying to keep costs down. Both tools have a reputation for being inexpensive, and both avoid the contact-based pricing that makes many email platforms painful for SaaS companies with lots of free users. But they are cheap at different jobs.
PostHog Workflows is cheap when you already pay for PostHog and want to send product-triggered messages. You build a workflow on events you already capture, and the first 10,000 messages per channel each month are free.
Brevo is cheap when you want a full messaging suite for a large list. It bundles marketing email, transactional email, SMS, WhatsApp, landing pages, and a CRM, and it charges by email volume rather than contacts.
Before comparing numbers, be clear about which job you are buying for.
Brevo pricing in practice
From our Brevo pricing notes:
| Plan | Starting price | What it adds |
|---|---|---|
| Free | $0 | Up to 300 emails per day, unlimited contacts, Brevo branding |
| Starter | From $9/month for 5,000 emails | Campaigns, editor, segmentation, e.g. $29/month for 20,000 emails |
| Standard | From $18/month for 5,000 emails | Marketing automation, A/B testing, advanced reporting, e.g. $65/month for 20,000 emails |
| Professional | From $499/month | Larger teams, more channels, deliverability support |
Two things stand out for a PostHog user. First, if you want Brevo to run automations like the ones you would build in PostHog Workflows, you are looking at Standard, not Starter. Second, SMS and WhatsApp credits are separate from the email plan.
PostHog Workflows has no plan tiers for this. You get 10,000 messages per channel free each month and pay per message after that.
What PostHog Workflows does that Brevo cannot
The advantage is proximity to product behavior. A workflow like "user created a dashboard but did not share it within 48 hours" is a cohort you may already have in PostHog. In Brevo, you would first need to send that behavior in as an event or contact attribute, keep names consistent, and then build the automation.
PostHog Workflows also handles internal actions well: post to a Slack channel when a trial account hits a usage milestone, call a webhook, update a person property. Brevo automations are customer-facing by design.
What Brevo does that PostHog Workflows cannot
- Transactional email. Brevo offers an SMTP relay and a transactional API that your app can call for receipts, password resets, and notifications. PostHog Workflows is not built to be your transactional provider.
- Campaigns. Newsletters, announcements, and promotions with a drag-and-drop editor and campaign reporting.
- More channels. WhatsApp campaigns and a broader SMS offering.
- Acquisition tooling. Forms, landing pages, and a sales CRM with deals.
If your email program includes a monthly newsletter and a product launch or two a quarter, Brevo covers that. PostHog Workflows does not try to.
The daily cap and account approval
Two operational details surprise teams trying Brevo for the first time. The free plan limits you to 300 emails per day, which is fine for testing but will not cover an onboarding sequence once signups grow. And our pricing notes describe the free allowance as available after account approval, so plan for a short review before you can send at all.
PostHog Workflows has neither constraint in the same form. The limit is a monthly free allowance of 10,000 messages per channel, after which you pay per message. If you are migrating live onboarding email, move to a paid Brevo plan before cutover rather than discovering the daily cap on a busy signup day.
Contact attributes versus cohorts
Brevo segments on contact attributes, list membership, and email engagement. PostHog Workflows targets cohorts built from event history, such as "did X at least three times in the last 14 days." Those are different data models.
When you sync through the Brevo destination, you are flattening behavior into attributes. That works for stable facts like plan name or signup date. It works less well for rolling windows, because an attribute is only as fresh as the last event that updated it. For time-based behavior, compute the cohort in PostHog and sync a simple flag, rather than trying to rebuild the logic in Brevo.
Connecting the two
PostHog has a Brevo destination that creates and updates Brevo contacts from PostHog events. That makes a common setup possible:
- Keep PostHog as the source of product events and cohorts.
- Use the Brevo destination to sync the attributes Brevo needs, such as plan, signup date, or activation status.
- Build lifecycle automations and campaigns in Brevo on those attributes.
- Keep internal alerts and webhooks in PostHog Workflows.
The work is in deciding which attributes to sync and keeping them accurate. Every automation in Brevo is only as good as the data the destination delivers.
Switching from PostHog Workflows to Brevo
If you are moving customer email out of PostHog, here is what actually transfers:
- People: synced as Brevo contacts through the destination, including email and the properties you choose.
- Cohorts: rebuilt as Brevo segments using synced attributes. Behavioral cohorts need a matching attribute or event in Brevo.
- Workflows: recreated as Brevo automations. Slack and webhook steps stay in PostHog.
- Templates: copy your HTML or rebuild in Brevo's editor.
- Domain: authenticate your sending domain with Brevo before the first live send.
- Unsubscribes: import suppressions so nobody who opted out gets mail from the new tool.
Migrating from Brevo to PostHog Workflows
Some teams go the other way: they started on Brevo for campaigns and want product nudges closer to analytics.
| Item | What to do |
|---|---|
| Automations triggered by product attributes | Rebuild as PostHog workflows on the matching cohort |
| Newsletters and promotions | Keep in Brevo; PostHog Workflows is not a campaign tool |
| Transactional email | Keep on Brevo's relay or API |
| Unsubscribes | Share suppressions so both tools respect opt-outs |
| Sending domain | Authenticate the same domain in PostHog with its own DKIM record |
| Attribute syncs | Retire attributes that only existed to feed moved automations |
Use-case matchups
| Need | Better fit | Why |
|---|---|---|
| Nudge users who created but did not share a dashboard | PostHog Workflows | Behavioral cohort already exists |
| Monthly newsletter to 50,000 contacts | Brevo | Volume pricing with unlimited contacts |
| Password reset and receipt email | Brevo | SMTP relay and transactional API |
| WhatsApp promotion | Brevo | Channel supported with credits |
| Internal alert on a usage spike | PostHog Workflows | Slack and webhook steps |
| Trial ending and dunning with Stripe data | Sequenzy | Native billing context |
A worked example
Suppose you have 8,000 users, about 1,500 new signups a month, and you want a three-email onboarding sequence plus a monthly product newsletter.
- Onboarding: 1,500 signups times 3 emails is about 4,500 emails a month. In PostHog Workflows that sits inside the 10,000 free email messages, so it may cost nothing.
- Newsletter: 8,000 emails a month. PostHog Workflows is not built for this, so you would need another tool anyway.
- Everything in Brevo: roughly 12,500 emails a month. Brevo Starter lists $29 per month for 20,000 emails, but onboarding automation points you to Standard, which lists $65 per month for 20,000 emails.
The numbers show the pattern. PostHog Workflows is the cheapest way to run product nudges. Brevo becomes the better value once campaigns join the picture, because one account covers both jobs.
Decision checklist
- Is most of your email campaigns or product nudges? Campaigns point to Brevo, nudges to PostHog Workflows.
- Do you need a transactional sender? Brevo covers it. PostHog Workflows does not.
- Will you need automation? Budget for Brevo Standard, not Starter.
- Are WhatsApp or SMS campaigns on the roadmap? Brevo supports them with separate credits.
- Is billing state central to your email? Neither tool models it natively.
Where Sequenzy fits
Brevo is a strong general tool, and if you want WhatsApp, a CRM, and landing pages for a small business, it is hard to beat on price. Sequenzy is narrower. It is built for SaaS lifecycle email: onboarding, activation, trial conversion, failed payment recovery, upgrade prompts, and transactional email, with Stripe connected so billing state drives sequences directly.
Sequenzy prices by emails sent with unlimited contacts, like Brevo. The comparison plan at 10,000 contacts is $49/month for 60k emails (unlimited subscribers). PostHog remains your analytics layer.
Summary
PostHog Workflows is the low-effort way to react to product behavior. Brevo is the low-cost way to run a broad messaging suite. Sequenzy is the focused choice when your SaaS lifecycle email needs billing context and a single home.
