Features
Every capability your team needs. Built so your whole team can use them.
Templates anyone can write. Flows triggered by what your customers actually do. Segments built without SQL. Reports that answer real questions. A developer experience your engineers will respect. Built around the Smart Suggester — so the same platform serves the marketer, the developer, and the reviewer.
Templates anyone can write — the Smart Suggester.
The Smart Suggester turns templating from a syntax problem into a selection problem. Pick a category, pick a feature, see the syntax with parameters and example output, press Enter. Schema-aware variables drawn from your live workspace. Eight categories — Variables, Conditions, Loops, Format, Filters, Totals, Display, Advanced. Works with NLT — Synapse’s own designed language — and with Jinja today. More languages on the roadmap.
- Multi-language engine — Use NLT for plain-English readability or Jinja if your team has standardised on it. Same Suggester, both languages.
- Schema-aware variable picker — Variables are drawn from your live workspace. Renamed fields update automatically. No {{first_name}} rendering as {{first_name}} in production.
- 19 chainable filters — Trim, truncate, capitalise, sort, deduplicate, join. Compose left-to-right in the order you'd describe the operation.
- 17 currency formats — USD, EUR, GBP, JPY, VND, and 12 more. Locale-correct symbols and separators handled by the engine.
- Required modifier — Mark fields as required and missing values suppress the entire send, with a structured log entry. The Hi {{first_name}}, class of bug becomes structurally impossible.
- HTML escaping by default — Every value rendered is HTML-escaped. XSS and HTML injection are not configuration concerns.
- AI assistant in the editor — When picker-based authoring isn't enough, Synapse Chat reads your template, applies edits, and explains errors with severity badges.
Generated by the Smart Suggester
{the user's First Name, or "there"}Welcome Flow
ActiveFlows triggered by what your customers actually do.
Any business event becomes a trigger. Build customer journeys in a visual canvas — no flowchart software, no engineering tickets, no half-finished sequences sitting in someone’s drafts. Drag, drop, branch, wait, send. Version history tracks every change. Performance metrics close the loop on every flow.
- 4 trigger types — Event-based, scheduled, periodic, and flow-exit. Match any pattern your business produces.
- Visual canvas editor — Drag-and-drop builder with steps for sending, waiting, branching, and updating contacts.
- 20+ email block types — Text, image, button, columns, video, code, and more. Desktop and mobile preview built in.
- Entry conditions — Qualify which contacts enter a flow. Combine segment rules with event attributes.
- Flow versioning — Draft, activate, pause, and stop flows. Version history tracks every change.
- Performance tracking — Trips started, trips completed, and conversion rates for every flow.
Build segments with rules, not queries.
Visual rule builder with real-time match estimates. Combine rules with all/any logic across thirteen operators that adapt to the field type. Build the audience you want without writing SQL or filing a ticket with your data team.
- Visual filter builder — Combine rules with all/any logic. 13 filter operators adapt to field type.
- Real-time match estimates — See how many contacts match each rule as you build it.
- RFM-based segments — Use Recency, Frequency, and Monetary scores as segment conditions. Target Champions, At Risk, or any of the 10 auto-generated cohorts.
Segment Builder
RFM Heatmap
10 segmentsRecency (top) × Frequency (left)
Contacts and RFM — the data model underneath.
Every segment, template variable, and flow condition draws from the same contact data model. Custom properties, nested fields, full event history, and built-in RFM scoring that turns raw transaction data into actionable cohorts — without a data team or an export.
- Full activity timeline — Every contact shows their complete history of events, emails sent, and flow trips — searchable and filterable.
- Custom properties — Define any field your business needs. Nested objects, arrays, dates, numbers — the schema adapts to your data.
- RFM scoring — Three-dimension scoring (Recency, Frequency, Monetary), each rated 1-5. Configurable events, attributes, and date ranges.
- 10 auto-generated segments — Champions, Loyal, Potential Loyalist, New Contacts, Promising, Needs Attention, About to Sleep, At Risk, Cannot Lose Them, Hibernating.
- RFM heatmap — 5×5 visual grid showing the distribution of your contacts across Recency and Frequency dimensions.
- Contact management — Search, sort, filter, and bulk-edit. Import and export. API access for every operation.
Open rate
68.4%
+5.2%
Click rate
24.1%
+3.8%
Delivered
12.8K
+23%
Weekly performance
Analytics that answer the questions your team actually asks.
Sends, opens, clicks, bounces — and beyond. Custom report builder with six chart types, cohort retention curves, funnel analysis, and side-by-side flow comparison. The same team that ships the campaign learns from the campaign, without exporting to a spreadsheet.
- Custom report builder — Choose metrics, dimensions, and filters. 6 chart types.
- Cohort retention — Track weekly or monthly cohorts to see engagement over time.
- Funnel analysis — Visualize triggered, sent, delivered, opened, clicked.
- Flow comparison — Compare flows side by side to find what works.
- Scheduled reports — Auto-deliver reports to your team. Shareable links for stakeholders.
- Email audit trail — Full email logs with search, filtering, and detail panels.
Send from your domain in minutes. Not hours.
SPF, DKIM, and DMARC are critical for deliverability — and the configuration is where most teams lose a day. Synapse detects your DNS provider, generates the right records, and verifies them as they propagate. Cloudflare users get one-click setup via Domain Connect.
- One-click setup for Cloudflare — If your domain uses Cloudflare, Synapse configures all DNS records automatically via Domain Connect. No copying, no pasting, no typos.
- 15 DNS providers detected — Synapse identifies your DNS provider instantly and links directly to their management panel. Cloudflare, Namecheap, GoDaddy, Route 53, Google Cloud DNS, and more.
- Automated verification — After DNS records are configured, Synapse monitors propagation and verifies automatically. No manual refresh needed.
- Per-record status — See exactly which records are verified and which need attention. Fix one without re-checking all three.
Sender Domain
VerifiedPOST /v1/events
X-WORKSPACE-ID: ws_abc123
X-API-KEY: psk_live_a1b2...
{
"event": "user_signed_up",
"contact": { "email": "[email protected]" },
"attributes": { "plan": "starter" }
}The developer experience your engineers will respect.
A clean REST API across 17 resource areas. Webhooks for every event you’d want to subscribe to. Type-safe SDKs for eight languages. Scoped API keys with four permission levels. A complete developer hub with reference docs, integration guides, and a dead letter queue inspector. Integrate in hours; hand off the templates to your marketing team forever.
- 8 SDKs — Node.js, Python, Ruby, PHP, Go, Java, .NET, and Browser. Type-safe client libraries for every major language.
- 17 API resources — Full CRUD for contacts, flows, templates, segments, reports, RFM, billing, workspace, and more.
- Events API — POST /v1/events with workspace ID and API key authentication. Sub-200ms ingestion at p99.
- Webhooks — Callbacks for delivery, opens, clicks, bounces, billing events, and payment events.
- Scoped API keys — Four scope levels: data, reporting, management, and full. Every integration carries minimum authority.
- Jinja2 migration toolchain — Bidirectional converter with language detection, batch conversion, and round-trip preservation.
Design in test. Ship to live with one click.
Most platforms force you to choose between safe and convenient. Synapse gives you both. Test and live environments are fully isolated — separate templates, flows, segments, contacts, events, and analytics. Build with confidence in test, with real emails sent to verified team addresses, then clone the lot to production in a single action. Available on every plan, including Free. No premium gate on safe deployment.
- Full data separation — Every resource lives in its own environment. Test contacts never mix with live contacts. Test events never trigger live flows.
- Real emails in test mode — No sandboxes or simulations. Test mode sends actual emails to verified team addresses so you catch rendering and deliverability issues before launch.
- One-click clone to live — When your template, flow, or segment is ready, clone it from test to live in a single action. No re-creating, no copy-paste, no missed settings.
- Separate analytics per environment — Test sends and live sends have independent metrics. Your production analytics stay clean while you iterate freely in test.
- Available on every plan — Test and live environments are included on all plans, from Free to Enterprise. No premium gate on safe deployment.
Deployment workflow
test/liveBuild in test
Templates, flows, segments
Send test emails
Real delivery to verified addresses
Clone to live
One click, everything transfers
What gets cloned
See every capability working together.
Free tier: 2,000 emails/month, 2,000 contacts, every capability available from the first send. No credit card required, no feature paywalls.