SIMID (Secure Interactive Media Interface Definition) is the IAB Tech Lab standard for interactive ad experiences in CTV and video. It replaces VPAID — which was designed for desktop and never worked cleanly on TV — with a sandboxed, secure communication protocol that lets an HTML/JavaScript creative layer interact with the video player without security risks or playback control. For India advertisers and publishers exploring interactive CTV formats, SIMID is the only standards-compliant path.
What is SIMID
SIMID defines a JavaScript API that sits between an interactive ad creative (running in an isolated iframe) and the video player. The creative cannot control the player directly — it sends messages through the SIMID API, and the player decides how to respond. This sandboxing was the core problem with VPAID: VPAID creatives ran inside the player with full JavaScript access, creating security vulnerabilities and playback reliability issues.
SIMID was ratified by IAB Tech Lab in 2020 and is now considered the standard for interactive video and CTV advertising. It works alongside VAST 4.x — VAST carries the SIMID creative reference, and SIMID handles the interactive layer communication during playback.
SIMID vs VPAID: what changed
| Dimension | VPAID | SIMID |
|---|---|---|
| Security model | Creative runs inside player; full JS access | Creative in isolated iframe; message-passing API |
| Player control | Creative can pause, skip, resize player | Creative requests actions; player decides |
| CTV compatibility | Poor (Flash-era, no TV app support) | Designed for CTV from the start |
| Measurement | Unreliable (creative could self-report) | Player controls measurement; more trustworthy |
| Adoption | Being deprecated; many SSPs blocking VPAID | Active standard; growing platform support |
Interactive experiences SIMID enables
QR code overlays: The most common SIMID use case in India CTV. A QR code appears over the video ad (or after it), allowing the viewer to scan with their phone and continue the journey on mobile. The SIMID creative renders the QR overlay; the player controls ad playback. No risk of the interactive layer breaking the video.
Remote-triggered choices: On CTV apps that support D-pad navigation, the viewer can use their remote to select from on-screen options (e.g., "Learn More" / "Get Offer" / "Watch Again"). SIMID passes the selection event to the creative, which can fire tracking pixels or load different content panels.
Second-screen sync: The ad creative can communicate with a companion ad on the viewer's phone (via a synchronisation mechanism in the publisher's app). Used for simultaneous mobile offers during TV ad exposure.
Dynamic overlays: Price feeds, countdown timers, and product information can be rendered as an HTML overlay on top of the video. SIMID ensures the overlay stays in sync with the video state (paused, completed, skipped).
Technical architecture
SIMID operates on a handshake model:
- VAST creative tag references a SIMID creative (an HTML file)
- Video player creates an isolated iframe and loads the SIMID creative inside it
- Player and creative exchange
postMessagecalls using the SIMID message protocol - Creative registers event listeners for player state (ad start, pause, complete, skip)
- Creative sends requests to player (e.g., "expand my overlay to full screen"); player evaluates and responds
- Player controls all playback and measurement; creative cannot override
SIMID creative files are typically 100–300KB HTML/JS files hosted on the advertiser's CDN. The VAST wrapper references them via the <MediaFile apiFramework="SIMID"> tag (VAST 4.x).
India adoption status (2026)
SIMID adoption in India is early but growing:
- JioHotstar: SIMID support available on smart TV app; QR code overlays live for select advertisers. Not yet available for programmatic demand — direct deals only.
- SonyLIV: SIMID in testing for smart TV; currently available only via direct insertion orders.
- Zee5: No confirmed SIMID support as of mid-2026.
- Samsung Ads / LG Ads: Home screen and ACR-triggered interactive formats use proprietary interaction models, not SIMID.
- YouTube CTV: Google uses its own interactive ad SDK, not SIMID. Interactive features on YouTube TV / YouTube CTV are platform-specific.
VPAID is still in circulation in India for desktop video, but major India SSPs (Magnite, PubMatic) are flagging VPAID creatives and encouraging migration to SIMID + VAST 4.
Practical use for India advertisers
QR code overlays are the most practical SIMID use case for India right now — the technology is available, the second-screen behaviour is natural in Indian households (everyone has their phone while watching TV), and the scan-to-mobile journey works well for e-commerce, app installs, and lead generation.
To run a SIMID QR overlay campaign: work directly with the publisher's integrated solutions or brand partnerships team. As of 2026, this is not available through the open programmatic stack for India. Budget for direct-deal minimums (typically ₹10–25L for a custom interactive campaign). Creative must be built to SIMID spec with the QR code rendering handled in the HTML creative layer — not baked into the video itself.