Synthesia’s help center distinguishes an Interactive Avatars API from a Legacy v2 Video API.
One brand contains different API contracts
As of the 25 October 2026 verification checkpoint, it lists interactive access on all plans, but legacy v2 access only for Pro and Enterprise. This is a product entitlement difference: an application with an interactive-avatar key cannot assume it can render scripted videos through the legacy service. Conversely, owning an older key does not authorize the new interactive endpoint.
Key scopes and endpoints
The vendor documents `developers.synthesia.io/api` for Interactive Avatars and `api.synthesia.io/v2` for the Legacy v2 API. Each key has its own scope. An engineering team should hold keys in a secret manager, tag them by approved API surface, set a renewal owner and rotate them before expiry. The help guide explains that keys may expire after seven, thirty or ninety days, a year or never, and the user sees their complete key once on creation. A secure integration should not log that key in webhook payloads or error messages.
A template-driven video example
Suppose an internal compliance group wants localized onboarding modules with an approved avatar. Keep the master script, source-of-truth policy, subtitle language and expiration date in the content management system. The rendering system should take only approved fields, submit a job using the correct API scope, verify completion and send the resulting draft for human proofreading. Train reviewers to watch for altered product rules and mistranslations; the fact that a video engine can render at scale does not establish content accuracy.
Asynchronous processing and account transitions
Treat each completed video as a versioned artifact linked to its source script and approved presenter. Build a resumeable job ledger even if the rendering API does not promise exactly-once semantics. The vendor warns that keys owned by departing workspace members are disabled, so long-running automations should be owned by a stable service or employee account under company policy. Plan usage deductions and API rate limits per account, not by reverse engineering another vendor’s public plan.
Separate Studio features from API promises
Synthesia also advertises in-product agent-like video creation features, including Syren, with their own plan controls and watermarks. Their availability does not automatically imply parity in the legacy video API. Check the explicit API surface before stating supported maximum length, resolution, rendering time or asset-generation model. Avoid collecting participant voices without consent and independently clear any company footage, fonts or music added in post-production.
Relevant alternatives and trade-offs
For real-time dialogue, evaluate the Interactive Avatars surface. For a camera-first video, normal editing or a consented recorded speaker may be more controllable than large-scale synthetic presentation.