Overview
Reelevant offers three complementary approaches for website personalisation. Choose one or combine them depending on your requirements:Reelevant Client Side Script
A JavaScript tracking script that loads in the browser, fetches personalised content, and injects it into your page. Ideal for event tracking, consent-dependent content, overlays, and no-code integrations via the browser extension.
Reelevant Server Side SDK
A Node.js / Edge SDK that fetches personalised content during server render. Content arrives in the initial HTML — zero layout shift, full SEO visibility, instant display.
Reelevant as API (JSON)
A headless personalisation API that returns structured JSON. You control the rendering — use your own components, design system, or native mobile UI with personalised data from Reelevant.
When to use which
| Client-Side Script | Server-Side SDK | API (JSON) | |
|---|---|---|---|
| How it works | JavaScript loads after page render, fetches content, injects into DOM | Content fetched during server render, included in HTML response | Your app calls the runner and receives structured JSON data |
| Layout shift (CLS) | Content appears after load — visible shift | Zero — content is in the initial HTML | You control rendering — no CLS if data is fetched server-side |
| SEO | Not indexed (injected after page load) | Fully indexed by search engines | Depends on your rendering strategy |
| Time to content | Depends on client network + runner latency | Included in first paint | Depends on when you call the API |
| Best for | Event tracking, consent, dynamic overlays, SPAs, no-code setup | Hero banners, product recommendations, landing pages, SEO-critical zones | Custom UI components, mobile apps, headless architectures, design systems |
| Setup effort | Paste a script tag or use the browser extension | Install an npm package and add server-side code | Create a JSON Template, call a single endpoint |
data-rlvt-ssr="true" — the client script automatically skips them. JSON API calls can be made from either client or server depending on your architecture.
Content types
The Reelevant runner can return three content formats. Your workflow’s output node determines which format is used:| Type | Description | Use case |
|---|---|---|
| HTML | Responsive HTML partial | Banners, product cards, rich content blocks |
| JSON | Structured data object | Headless personalisation — build your own UI with personalised data |
| Image | Binary image (PNG, etc.) | Static visual banners, email-style images on web |
Identity management
All three approaches share the same identity cookies:| Cookie | Purpose |
|---|---|
rlvt_clientId | Known user identity (set by your application or the client tracker) |
rlvt_tmpId | Anonymous visitor ID (set automatically by the script or SDK middleware) |
rlvt_clientId > rlvt_tmpId. If neither exists, the script or SDK middleware generates a new rlvt_tmpId automatically.