Credits & Billing API

Check your credit balance, estimate job costs, browse model pricing, view transaction history, and purchase credit packs. 1 credit = $0.01 USD.

Credit Packs

Prepaid credit packs are the only way to add credits. Larger packs offer volume discounts up to 40%.

Pack	Price	Credits	Per Credit	Savings
Starter `starter`	$10	200	$0.050	—
Creator `creator`	$45	1,000	$0.045	10%
Studio `studio`	$175	5,000	$0.035	30%
Enterprise `enterprise`	$600	20,000	$0.030	40%

Credit Lifecycle

When a job is created, credits are reserved from your available balance. When the job completes, credits are consumed (actual usage may differ from the estimate). If a job fails or is cancelled, reserved credits are released back to your balance.

Get Credit Balance

Retrieve your current credit balance, reserved credits for in-flight jobs, and available credits.

GET/api/v1/credits/balance

• available_credits = credit_balance − credit_reserved.

• Reserved credits are automatically released when a job completes, fails, or is cancelled.

• Check available_credits before creating a job to avoid 402 Insufficient Credits errors.

Request Example

curl -X GET https://api.u-gen.ai/api/v1/credits/balance \
  -H "X-API-Key: YOUR_API_KEY"

List Credit Transactions

Retrieve a paginated history of all credit movements: purchases, reservations, consumption, releases, refunds, and bonuses.

GET/api/v1/credits/transactions

• Transaction types: purchase, reserve, consume, release, refund, bonus.

• Positive amounts are credits added (purchase, release, refund, bonus). Negative amounts are credits removed (reserve, consume).

• Each transaction records balance_before and balance_after for a full audit trail.

Parameters

Parameter Type Description

Parameter	Type	Description
`page`	integer Default: 1	Page number. Min 1
`page_size`	integer Default: 20	Results per page. 1–100
`job_id`	string (UUID)	Filter transactions for a specific job.

page

integer

Default: 1

Page number.

Min 1

page_size

integer

Default: 20

Results per page.

1–100

job_id

string (UUID)

Filter transactions for a specific job.

Request Example

curl -X GET "https://api.u-gen.ai/api/v1/credits/transactions?page=1&page_size=10" \
  -H "X-API-Key: YOUR_API_KEY"

Estimate Job Credits

Calculate the total credits required for a job before creating it. Returns a detailed breakdown by cost component.

POST/api/v1/credits/estimate

• The breakdown shows each cost component independently so you can see where credits go.

• Keyframe generation uses NanoBanana 2: 8 credits (1k), 12 credits (2k), or 18 credits (4k) per keyframe. N segments = N+1 keyframes.

• Kling models use per-second billing (credits × duration × segments). Veo and Sora use flat per-generation billing.

• QA retries are budgeted at 50% of the base cost per retry attempt.

• HITL rejections are budgeted at 100% of the base cost per rejection.

Body

Parameter	Type	Description
`segment_count`REQ	integer	Number of video segments. 1–10
`model_id`	string Default: veo3_fast	Video model ID.
`variant`	string Default: i2v	Generation variant for pricing lookup. i2vt2vr2vwith_audiowith_audio_720pno_audio
`duration_seconds`	integer Default: 8	Per-segment duration (affects per-second models like Kling). 1–30
`resolution`	string Default: standard	Video resolution. standard1080p4k
`keyframe_resolution`	string Default: 1k	Keyframe image resolution (NanoBanana 2). 1k2k4k
`caption_style`	string Default: tiktok_karaoke	Caption style. "custom" adds extra credits.
`music_enabled`	boolean Default: true	Background music.
`voice_enabled`	boolean Default: false	ElevenLabs voice-over.
`custom_voice`	boolean Default: false	User selected a custom voice from the library.

Body (QA)

Parameter Type Description

Parameter	Type	Description
`qai_enabled`	boolean Default: false	AI Quality Assurance enabled.
`max_kf_retries`	integer Default: 0	Max keyframe retries (when QA on). 0–5
`max_video_retries`	integer Default: 0	Max video retries (when QA on). 0–5

qai_enabled

boolean

Default: false

AI Quality Assurance enabled.

max_kf_retries

integer

Default: 0

Max keyframe retries (when QA on).

0–5

max_video_retries

integer

Default: 0

Max video retries (when QA on).

0–5

Body (HITL)

Parameter	Type	Description
`human_review_gate`	boolean Default: false	Human review for anchor keyframe.
`hitl_anchor_max_rejections`	integer Default: 0	Max anchor rejections. 0–5
`human_review_videos`	boolean Default: false	Human review for video segments.
`hitl_segments_max_rejections`	integer Default: 0	Max segment rejections per segment. 0–3

Request Example

curl -X POST https://api.u-gen.ai/api/v1/credits/estimate \
  -H "X-API-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "segment_count": 3,
    "model_id": "veo3_fast",
    "variant": "i2v",
    "duration_seconds": 8,
    "resolution": "standard",
    "keyframe_resolution": "1k",
    "music_enabled": true,
    "voice_enabled": true
  }'

Pre-Flight Cost Check

Call the Estimate endpoint before creating a job to show the user an accurate credit cost. The same estimation logic is used internally when the job is actually created.

List Model Pricing

Retrieve per-variant pricing for all active models. Use this to build pricing tables or calculators.

GET/api/v1/credits/pricing

• Returns a bare array of all active model variant prices.

• billing_unit is either "per_generation" (flat cost) or "per_second" (cost × duration).

• kie_cost_usd is the upstream provider cost. price_usd is the marked-up price. credits = price_usd × 100.

Parameters

Parameter	Type	Description
`model_id`	string	Filter by model ID (e.g., veo3_fast, kling3_std).

Request Example

curl -X GET "https://api.u-gen.ai/api/v1/credits/pricing?model_id=veo3_fast" \
  -H "X-API-Key: YOUR_API_KEY"

List Credit Packs

Retrieve available credit packs with pricing. No authentication required.

GET/api/v1/billing/packs

• Public endpoint — no API key required.

• savings_pct is the percentage discount compared to the Starter pack rate.

Request Example

curl -X GET https://api.u-gen.ai/api/v1/billing/packs

Create Checkout Session

Start a Stripe or PayPal checkout session to purchase a credit pack. Redirect the user to the returned URL to complete payment.

POST/api/v1/billing/checkout

• Redirect the user to checkout_url to complete payment.

• For card payments, a Stripe Checkout session is created. For PayPal, a PayPal Order is created.

• Credits are added to the account automatically after payment is confirmed via webhook.

• session_id can be used to track the payment status.

Body

Parameter	Type	Description
`pack_id`REQ	string	Credit pack to purchase. startercreatorstudioenterprise
`payment_type`	string Default: card	Payment method. cardpaypal

Request Example

curl -X POST https://api.u-gen.ai/api/v1/billing/checkout \
  -H "X-API-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"pack_id": "creator", "payment_type": "card"}'

Additional Billing Endpoints

The Billing API also includes endpoints for managing saved payment methods (GET /billing/payment-methods, DELETE /billing/payment-methods/{id}), auto-topup configuration (GET/POST /billing/auto-topup), and low-balance email alerts (GET/POST /billing/credit-alert).

Retry Credits

Retrying a failed job re-reserves credits from the restart stage onward. Check your available_credits before retrying to avoid 402 Insufficient Credits errors.