[Feature Request] Add Veo 3.1 Lite model support for video generation

[sofyanlabs]

Veo 3.1 Lite was released by Google on March 31, 2026 as a cost-effective video generation model (less than 50% cost of Veo 3.1 Fast with same speed). However, when attempting to use Veo 3.1 Lite model keys via FlowKit's video generation pipeline, the model is not recognized/found.

Expected Behavior

FlowKit should support Veo 3.1 Lite as a video model option, allowing users to configure it via the /api/flow/settings endpoint or model configuration. Expected model keys:

• veo_3_1_i2v_lite_portrait (9:16)
• veo_3_1_i2v_lite_landscape (16:9)

Current Behavior

When setting video models to Veo 3.1 Lite variants via the settings API (video_models.PAYGATE_TIER_TWO.frame_2_video), video generation fails with model not found or the request is rejected by the Google Flow API.

The current hardcoded VIDEO_MODELS in flow_client.py only includes Veo 3.1 (standard/fast) but not the Lite variant.

Steps to Reproduce

1. Configure FlowKit video model settings to use Veo 3.1 Lite:
   {
   "video_models": {
   "PAYGATE_TIER_TWO": {
   "frame_2_video": {
   "VIDEO_ASPECT_RATIO_PORTRAIT": "veo_3_1_i2v_lite_portrait",
   "VIDEO_ASPECT_RATIO_LANDSCAPE": "veo_3_1_i2v_lite_landscape"
   },
   "start_end_frame_2_video": {
   "VIDEO_ASPECT_RATIO_PORTRAIT": "veo_3_1_i2v_lite_portrait",
   "VIDEO_ASPECT_RATIO_LANDSCAPE": "veo_3_1_i2v_lite_landscape"
   }
   }
   }
   }

2. Trigger video generation via /fk-gen-videos or API

3. Generation fails — model not found

Context

• Veo 3.1 Lite is available via Gemini API and Google AI Studio (paid tier)
• It supports both text-to-video and image-to-video (i2v)
• Output: 720p/1080p, 9:16 and 16:9, 4/6/8 second clips
• Cost: <50% of Veo 3.1 Fast
• Speed: Same as Veo 3.1 Fast

Suggested Fix

Add Veo 3.1 Lite model keys to the VIDEO_MODELS dictionary and expose them as a selectable tier option (e.g., alongside existing TIER_ONE/TIER_TWO models), or allow the model key to be fully user-configurable without validation against a hardcoded list.

Environment

• FlowKit version: latest (main branch)
• Google account tier: PAYGATE_TIER_TWO
• OS: Windows 11 + Chrome extension

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