> ## Documentation Index
> Fetch the complete documentation index at: https://docs.venice.ai/llms.txt
> Use this file to discover all available pages before exploring further.
# Generate Images
> Generate an image based on input parameters
**Authentication:** This endpoint accepts either a Bearer API key or a `SIGN-IN-WITH-X` header for x402 wallet-based authentication. The legacy `X-Sign-In-With-X` header is also accepted during migration. When using x402, a `402 Payment Required` response indicates insufficient balance and includes top-up instructions.
## Sizing Options
Image models use model-specific sizing parameters:
* Pixel-based models accept `width` and `height`, for example `venice-sd35` and `qwen-image`.
* Aspect-ratio models accept `aspect_ratio`, for example `qwen-image-2`.
* Resolution-tier models accept both `aspect_ratio` and `resolution`.
For example, `gpt-image-2`, `nano-banana-2`, and `nano-banana-pro` support `resolution` values of `1K`, `2K`, and `4K`:
```json theme={"system"}
{
"model": "gpt-image-2",
"prompt": "a cinematic wide shot of Venice at sunset",
"aspect_ratio": "16:9",
"resolution": "4K",
"format": "png"
}
```
The same resolution-tier sizing pattern also applies to Nano Banana models:
```json theme={"system"}
{
"model": "nano-banana-pro",
"prompt": "a serene canal in venice at sunset",
"aspect_ratio": "16:9",
"resolution": "2K"
}
```
For models that accept aspect ratio but do not expose resolution tiers, send `aspect_ratio` without `resolution`:
```json theme={"system"}
{
"model": "qwen-image-2",
"prompt": "a serene canal in venice at sunset",
"aspect_ratio": "16:9"
}
```
For models that use direct pixel dimensions, send `width` and `height` instead:
```json theme={"system"}
{
"model": "venice-sd35",
"prompt": "a serene canal in venice at sunset",
"width": 1024,
"height": 1024
}
```
Check [Image Models](/models/image) or the [Models endpoint](/api-reference/endpoint/models/list) for each model's supported sizing options before mixing sizing fields across models.
## Quality Tiers
Some models accept an optional `quality` parameter (`low`, `medium`, `high`) that trades visual fidelity for cost. Currently supported by `gpt-image-2`; other models ignore the parameter.
```json theme={"system"}
{
"model": "gpt-image-2",
"prompt": "a cinematic wide shot of Venice at sunset",
"aspect_ratio": "16:9",
"resolution": "2K",
"quality": "medium"
}
```
When you omit `quality`, the model uses its default tier (`high` for `gpt-image-2`). Pricing depends on the combination of `resolution` and `quality` — the per-tier prices for `gpt-image-2` (1K/2K/4K × low/medium/high) are exposed under `model_spec.pricing.quality` in the [Models endpoint](/api-reference/endpoint/models/list) and listed in the [Pricing overview](/overview/pricing).
Quality-aware pricing is the default for all API and SDK callers — no opt-in header required. Requests that omit `quality` are billed at the model's default tier (`high` for `gpt-image-2`).
## Postman Collection
For additional examples, please see this [Postman Collection](https://www.postman.com/veniceai/workspace/venice-ai-workspace/folder/38652128-0adc004d-2edf-4b88-a3bb-0f868c791c9c?action=share\&source=copy-link\&creator=38652128\&ctx=documentation).
***
## OpenAPI
````yaml POST /image/generate
openapi: 3.0.0
info:
description: The Venice.ai API.
termsOfService: https://venice.ai/legal/tos
title: Venice.ai API
version: '20260626.184905'
x-guidance: >-
Venice.ai is an OpenAI-compatible inference API supporting text, image,
audio, and video generation.
**Authentication options:**
- API Key: Use Bearer token in Authorization header
- x402 Wallet: Use USDC credits via EVM or Solana wallet (no account
required)
**For x402 wallet access:**
1. POST /x402/top-up without headers to get payment requirements
2. Choose one of the returned Base or Solana payment options and sign a USDC
payment using the x402 SDK
3. POST /x402/top-up with PAYMENT-SIGNATURE header to add credits
4. Call any inference endpoint with SIGN-IN-WITH-X header
**Pricing:** Prepaid credits consumed per request. Check /models for
available models and their capabilities.
servers:
- url: https://api.venice.ai/api/v1
security:
- BearerAuth: []
tags:
- description: >-
Generate speech/audio, transcribe audio, and manage asynchronous audio
generation jobs.
name: Audio
- description: >-
Given a list of messages comprising a conversation, the model will return
a response. Supports multimodal inputs including text, images, audio
(input_audio), and video (video_url) for compatible models.
name: Chat
- description: List and describe the various models available in the API.
name: Models
- description: Generate and manipulate images using AI models.
name: Image
- description: Generate videos using AI models.
name: Video
- description: List and retrieve character information for use in completions.
name: Characters
- description: >-
Billing and usage analytics. **Beta**: This API is currently in beta and
may be unstable. Endpoints, request/response schemas, and behavior may
change without notice.
name: Billing
- description: Proxy JSON-RPC requests to blockchain nodes. Billed per credit.
name: Crypto RPC
- description: >-
Wallet-based API access using the x402 protocol. No API key required —
authenticate with an EVM or Solana wallet.
**How it works:**
1. **Authenticate** — Send a `SIGN-IN-WITH-X` header (base64-encoded
signed SIWX payload) with any request. EVM wallets sign an EIP-4361 SIWE
message; Solana wallets sign the Solana SIWX message with Ed25519. See the
`siwx` security scheme for the exact format.
2. **Top up** — `POST /x402/top-up` without a payment header returns an
`accepts` array with Base and Solana USDC payment options. Choose one
entry, sign it using the x402 SDK (`npm install x402`), and re-submit with
the `PAYMENT-SIGNATURE` header (the legacy `X-402-Payment` and `X-PAYMENT`
names are also accepted).
3. **Use any endpoint** — All inference endpoints (chat, image, audio,
video, embeddings) accept `siwx` as an alternative to `BearerAuth`.
Charges are deducted from your USDC credit balance.
4. **Monitor balance** — `GET /x402/balance/{walletAddress}` returns your
current balance. The `X-Balance-Remaining` response header on inference
calls also reports it.
**Quick start (5 lines):**
```
import { VeniceClient } from '@venice-ai/x402-client'
const venice = new VeniceClient(process.env.WALLET_KEY)
await venice.topUp(10) // $10 USDC on a supported x402 rail
const res = await venice.chat({ model: 'zai-org-glm-5-1', messages: [{
role: 'user', content: 'Hello!' }] })
```
**Payment:** USDC on Base (chain ID 8453) or Solana mainnet. Minimum
top-up: $5. Alternatively, stake DIEM tokens for daily credits (1 DIEM =
$1/day).
name: x402
externalDocs:
description: Venice.ai API documentation
url: https://docs.venice.ai
paths:
/image/generate:
post:
tags:
- Image
summary: /api/v1/image/generate
description: >-
Generate an image based on input parameters
**Authentication:** This endpoint accepts either a Bearer API key or a
`SIGN-IN-WITH-X` header for x402 wallet-based authentication. The legacy
`X-Sign-In-With-X` header is also accepted during migration. When using
x402, a `402 Payment Required` response indicates insufficient balance
and includes top-up instructions.
operationId: generateImage
parameters:
- description: >-
Supported compression encodings (gzip, br). Only applied when
return_binary is false.
in: header
name: Accept-Encoding
required: false
schema:
example: gzip, br
type: string
requestBody:
content:
application/json:
schema:
$ref: '#/components/schemas/GenerateImageRequest'
responses:
'200':
description: Successfully generated image
headers:
X-Balance-Remaining:
description: >-
Remaining x402 credit balance in USD after this request (only
present for x402 auth).
required: false
schema:
type: string
example: '4.230000'
Content-Encoding:
description: The encoding used to compress the response
schema:
enum:
- gzip
- br
type: string
x-venice-is-blurred:
description: >-
Indicates if the generated image is blurred. When Safe Venice is
enabled, adult material will be returned blurred.
required: false
schema:
type: boolean
x-venice-is-content-violation:
description: >-
Indicates if the generated image does not meet Venice terms of
service.
required: false
schema:
type: boolean
x-venice-model-deprecation-warning:
description: A warning that the model is scheduled for deprecation
required: false
schema:
type: string
x-venice-model-deprecation-date:
description: The date the model is scheduled for deprecation
required: false
schema:
type: string
format: date-time
x-venice-deprecated:
description: >-
Present and set to "true" when the model is deprecated. Absent
otherwise.
required: false
schema:
type: string
enum:
- 'true'
x-venice-deprecated-replacement:
description: >-
Public API model ID clients should migrate to. Only present when
a replacement is published.
required: false
schema:
type: string
content:
application/json:
schema:
type: object
properties:
id:
type: string
description: The ID of the request.
example: generate-image-1234567890
images:
type: array
items:
type: string
description: Base64 encoded image data.
request:
nullable: true
description: The original request data sent to the API.
timing:
type: object
properties:
inferenceDuration:
type: number
description: Duration of inference in milliseconds
inferencePreprocessingTime:
type: number
description: Duration of preprocessing in milliseconds
inferenceQueueTime:
type: number
description: Duration of queueing in milliseconds
total:
type: number
description: Total duration of the request in milliseconds
required:
- inferenceDuration
- inferencePreprocessingTime
- inferenceQueueTime
- total
required:
- id
- images
- timing
image/jpeg:
schema:
description: Raw image data when return_binary is true and format is jpeg
format: binary
type: string
image/png:
schema:
description: Raw image data when return_binary is true and format is png
format: binary
type: string
image/webp:
schema:
description: Raw image data when return_binary is true and format is webp
format: binary
type: string
'400':
description: Invalid request parameters
content:
application/json:
schema:
$ref: '#/components/schemas/DetailedError'
'401':
description: |-
- Authentication failed
- This model is only available to Pro users
content:
application/json:
schema:
$ref: '#/components/schemas/StandardError'
'402':
description: >-
Payment or balance required. Response varies by authentication
state:
**API Key users:** Standard error response with
`INSUFFICIENT_BALANCE` code. Top up your Venice balance at
venice.ai.
**Unauthenticated x402 discovery:** Structured x402 response with
`x402Version`, `resource`, `accepts`, and
`extensions["sign-in-with-x"]`. The `accepts` array advertises Base
and Solana payment requirements.
**Authenticated x402 wallet users with insufficient credit:**
Structured response with `PAYMENT_REQUIRED` code containing:
- `topUpInstructions`: Step-by-step guide to top up via x402
protocol
- `supportedTokens` / `supportedChains`: Accepted payment methods
- `siwxChallenge`: Fresh Sign-In-With-X challenge metadata
The `PAYMENT-REQUIRED` header also contains a base64-encoded x402
protocol object with the payment requirements for programmatic
discovery.
headers:
PAYMENT-REQUIRED:
description: >-
Base64-encoded JSON with x402 payment requirements. Present on
x402 middleware 402 responses. Decode to choose and sign one
accepted payment requirement programmatically.
required: false
schema:
type: string
content:
application/json:
schema:
oneOf:
- $ref: '#/components/schemas/StandardError'
- $ref: '#/components/schemas/X402InferencePaymentRequired'
'415':
description: Invalid request content-type
content:
application/json:
schema:
$ref: '#/components/schemas/StandardError'
'429':
description: Rate limit exceeded
content:
application/json:
schema:
$ref: '#/components/schemas/StandardError'
'500':
description: Inference processing failed
content:
application/json:
schema:
$ref: '#/components/schemas/StandardError'
'503':
description: The model is at capacity. Please try again later.
content:
application/json:
schema:
$ref: '#/components/schemas/StandardError'
security:
- BearerAuth: []
- siwx: []
components:
schemas:
GenerateImageRequest:
type: object
properties:
cfg_scale:
type: number
minimum: 0
exclusiveMinimum: true
maximum: 20
description: >-
CFG scale parameter. Higher values lead to more adherence to the
prompt.
example: 7.5
embed_exif_metadata:
type: boolean
default: false
description: Embed prompt generation information into the image's EXIF metadata.
example: false
format:
type: string
enum:
- jpeg
- png
- webp
default: webp
description: >-
The image format to return. WebP are smaller and optimized for web
use. PNG are higher quality but larger in file size.
example: webp
height:
type: integer
minimum: 0
exclusiveMinimum: true
maximum: 1280
default: 1024
description: Height of the generated image.
example: 1024
hide_watermark:
type: boolean
default: false
description: >-
Whether to hide the Venice watermark. Venice may ignore this
parameter for certain generated content.
example: false
inpaint:
nullable: true
description: >-
This feature is deprecated and was disabled on May 19th, 2025. A
revised in-painting API will be launched in the near future.
deprecated: true
lora_strength:
type: integer
minimum: 0
maximum: 100
description: >-
Lora strength for the model. Only applies if the model uses
additional Loras.
example: 50
model:
type: string
description: The model to use for image generation.
example: grok-imagine-image
negative_prompt:
type: string
maxLength: 7500
description: >-
A description of what should not be in the image. Character limit is
model specific and is listed in the promptCharacterLimit constraint
in the model list endpoint.
example: Clouds, Rain, Snow
prompt:
type: string
minLength: 1
maxLength: 7500
description: >-
The description for the image. Character limit is model specific and
is listed in the promptCharacterLimit setting in the model list
endpoint.
example: A beautiful sunset over a mountain range
return_binary:
type: boolean
default: false
description: Whether to return binary image data instead of base64.
example: false
variants:
type: integer
minimum: 1
maximum: 4
description: >-
Number of images to generate (1–4). Only supported when
return_binary is false.
example: 3
safe_mode:
type: boolean
default: true
description: >-
Whether to use safe mode. If enabled, this will blur images that are
classified as having adult content.
example: false
seed:
type: integer
minimum: -999999999
maximum: 999999999
default: 0
description: >-
Random seed for generation. If not provided, a random seed will be
used.
example: 123456789
steps:
type: integer
default: 8
description: >-
Number of inference steps. This model does not support steps - this
field is ignored.
example: 8
style_preset:
type: string
description: >-
An image style to apply to the image. Visit
https://docs.venice.ai/api-reference/endpoint/image/styles for more
details.
example: 3D Model
aspect_ratio:
type: string
description: >-
Aspect ratio (utilized by certain image models including Nano
Banana). Examples: "1:1", "16:9".
example: '1:1'
resolution:
type: string
description: >-
Resolution (utilized by certain image models including Nano Banana).
Examples: "1K", "2K", "4K".
example: 1K
quality:
type: string
enum:
- low
- medium
- high
description: >-
Output quality for supported models (e.g. GPT Image 2 / GPT Image 2
Edit). Higher values can increase the final request charge. See the
model list for supported options.
example: high
enable_web_search:
type: boolean
description: >-
Enable web search for the image generation task. This will allow the
model to use the latest information from the web to generate the
image. Only supported by certain models. If web search is used,
additional credits are getting charged.
example: false
width:
type: integer
minimum: 0
exclusiveMinimum: true
maximum: 1280
default: 1024
description: Width of the generated image.
example: 1024
required:
- model
- prompt
additionalProperties: false
DetailedError:
type: object
properties:
details:
type: object
properties: {}
description: Details about the incorrect input
example:
_errors: []
field:
_errors:
- Field is required
error:
type: string
description: A description of the error
required:
- error
StandardError:
type: object
properties:
error:
type: string
description: A description of the error
required:
- error
X402InferencePaymentRequired:
anyOf:
- type: object
properties:
x402Version:
type: number
description: x402 protocol version.
example: 2
error:
type: string
description: Human-readable payment requirement message.
example: Payment required
resource:
type: object
properties:
url:
type: string
description: Protected resource URL.
example: https://api.venice.ai/api/v1/chat/completions
description:
type: string
description: Human-readable resource description.
example: Venice API
mimeType:
type: string
description: Resource MIME type.
example: application/json
required:
- url
- description
- mimeType
additionalProperties: false
accepts:
type: array
items:
type: object
properties:
scheme:
type: string
enum:
- exact
description: x402 payment scheme.
example: exact
network:
type: string
description: Payment network for this requirement.
example: solana
asset:
type: string
description: USDC token address or mint for the selected network.
example: EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v
amount:
type: string
description: >-
Required payment amount in base units (USDC has 6
decimals).
example: '10000000'
payTo:
type: string
description: Receiver wallet address for the selected network.
example: 8qUL23aSj7mDWdoLMXGHFvnVCT9wd7jXcysiekroADEL
maxTimeoutSeconds:
type: number
description: Maximum time allowed for payment settlement.
example: 300
extra:
type: object
properties: {}
description: >-
Network-specific x402 metadata. Solana requirements
include a feePayer.
example:
name: USD Coin
version: '2'
feePayer: BFK9TLC3edb13K6v4YyH3DwPb5DSUpkWvb7XnqCL9b4F
required:
- scheme
- network
- asset
- amount
- payTo
- maxTimeoutSeconds
- extra
additionalProperties: false
description: >-
Protocol payment requirements. Clients should choose one entry,
such as Base or Solana, and sign exactly that requirement.
extensions:
type: object
properties: {}
description: >-
Protocol extensions. Inference 402 responses include
`sign-in-with-x` with a SIWX challenge for wallet-credit
authentication.
authOptions:
type: object
properties:
apiKey:
type: object
properties:
header:
type: string
description: API key authentication header format.
example: 'Authorization: Bearer YOUR_API_KEY'
getKey:
type: string
description: Where to create or manage API keys.
example: https://venice.ai/settings/api
docs:
type: string
description: API key documentation URL.
example: https://docs.venice.ai/api-reference
required:
- header
- getKey
- docs
additionalProperties: false
x402Wallet:
type: object
properties:
header:
type: string
description: Header used for Sign-In-With-X wallet authentication.
example: SIGN-IN-WITH-X
legacyHeader:
type: string
description: Legacy Sign-In-With-X header accepted during migration.
example: X-Sign-In-With-X
topUp:
type: string
description: >-
Endpoint used to discover and submit x402 top-up
payments.
example: POST /api/v1/x402/top-up
docs:
type: string
description: x402 top-up API documentation URL.
example: >-
https://docs.venice.ai/api-reference/endpoint/x402/top-up
required:
- header
- legacyHeader
- topUp
- docs
additionalProperties: false
required:
- apiKey
- x402Wallet
additionalProperties: false
required:
- x402Version
- resource
- accepts
- authOptions
additionalProperties: false
description: >-
Returned when an inference request has no API key or wallet
authentication. The JSON body includes x402 discovery requirements
and authentication options.
- type: object
properties:
error:
type: string
enum:
- Payment required
description: Error message indicating payment is required.
code:
type: string
enum:
- PAYMENT_REQUIRED
description: Machine-readable error code.
reason:
type: string
enum:
- insufficient_balance
description: Reason the x402-authenticated request could not proceed.
message:
type: string
description: Human-readable context about the payment requirement.
example: Insufficient x402 balance
currentBalanceUsd:
type: number
description: Current x402 credit balance for the wallet.
example: 0.01
minimumBalanceUsd:
type: number
description: Minimum x402 credit balance required before the request can run.
example: 0.1
description:
type: string
description: Protected resource description.
example: Venice API
suggestedTopUpUsd:
type: number
description: Suggested amount to top up in USD.
example: 10
minimumTopUpUsd:
type: number
description: Minimum allowed top-up amount in USD.
example: 5
supportedTokens:
type: array
items:
type: string
description: List of supported token symbols for payment.
example:
- USDC
supportedChains:
type: array
items:
type: string
description: List of supported top-up rails.
example:
- base
- solana
topUpInstructions:
type: object
properties:
step1:
type: string
description: 'First step: get payment requirements.'
example: >-
POST /api/v1/x402/top-up with no payment header to get
payment requirements
step2:
type: string
description: 'Second step: sign the payment.'
example: >-
Choose a payment option from accepts and sign a USDC
transfer authorization using the x402 SDK
(createPaymentHeader)
step3:
type: string
description: 'Third step: submit the payment.'
example: >-
POST /api/v1/x402/top-up with the signed PAYMENT-SIGNATURE
header
receiverWallet:
type: string
description: >-
Legacy Base receiver wallet address. Prefer the selected
accepts entry from /x402/top-up for network-specific payTo
values.
example:
tokenAddress:
type: string
description: >-
Legacy Base USDC token address. Prefer the selected accepts
entry from /x402/top-up for network-specific assets.
example:
tokenDecimals:
type: number
description: Token decimal places.
example: 6
network:
type: string
description: >-
Legacy Base target network. Prefer the selected accepts
entry from /x402/top-up for network-specific values.
example: eip155:8453
minimumAmountUsd:
type: number
description: Minimum top-up amount in USD.
example: 5
required:
- step1
- step2
- step3
- receiverWallet
- tokenAddress
- tokenDecimals
- network
- minimumAmountUsd
additionalProperties: false
siwxChallenge:
type: object
properties:
info:
type: object
properties:
domain:
type: string
description: Domain for the SIWX challenge.
example: api.venice.ai
uri:
type: string
description: Resource URI for the challenge.
example: https://api.venice.ai/api/v1/chat/completions
version:
type: string
description: SIWX version.
example: '1'
nonce:
type: string
description: Unique nonce for replay protection.
example: '{{nonce}}'
issuedAt:
type: string
description: ISO timestamp when the challenge was issued.
example: '2026-04-09T12:00:00.000Z'
expirationTime:
type: string
description: ISO timestamp when the challenge expires.
example: '2026-04-09T12:05:00.000Z'
statement:
type: string
description: Human-readable statement for the signature.
example: Sign in to Venice AI
required:
- domain
- uri
- version
- nonce
- issuedAt
- expirationTime
- statement
additionalProperties: false
supportedChains:
type: array
items:
type: object
properties:
chainId:
type: string
description: Supported chain identity.
example: solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp
type:
type: string
enum:
- eip191
- eip1271
- ed25519
description: Signature type accepted for this chain.
example: ed25519
required:
- chainId
- type
additionalProperties: false
description: Supported SIWX chains and signature types.
required:
- info
- supportedChains
additionalProperties: false
required:
- error
- code
- reason
- suggestedTopUpUsd
- minimumTopUpUsd
- supportedTokens
- supportedChains
- topUpInstructions
- siwxChallenge
additionalProperties: false
securitySchemes:
BearerAuth:
bearerFormat: JWT
scheme: bearer
type: http
siwx:
description: >-
Wallet-based authentication using the x402 protocol (Sign-In-With-X).
Supports EVM SIWE signatures on Base and Ed25519 signatures on Solana
mainnet.
**Header format:** Base64-encoded JSON object with the following fields:
- `address` — EVM or Solana wallet address
- `message` — Signed SIWX message. EVM wallets use EIP-4361 SIWE; Solana
wallets use the Solana SIWX message format.
- `signature` — Signature of the message, signed by the wallet's private
key. EVM signatures are hex; Solana signatures may be base58 or base64.
- `timestamp` — Unix timestamp in milliseconds
- `chainId` — Chain identity. Use `8453`, `"8453"`, or `"eip155:8453"`
for Base; use `"solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp"` for Solana.
- `type` — Optional signature type. Use `"ed25519"` for Solana. Omitted
means EVM/EIP-191 for backward compatibility.
**EVM SIWE message fields:**
- `domain`: `api.venice.ai`
- `uri`: `https://api.venice.ai`
- `version`: `"1"`
- `chainId`: `8453`
- `nonce`: Random 16-character hex string
- `issuedAt` / `expirationTime`: ISO timestamps (recommended TTL: 10
minutes)
- `statement`: `"Sign in to Venice API"`
**Example (TypeScript):**
```
import { Wallet } from 'ethers'
import { SiweMessage } from 'siwe'
const wallet = new Wallet(PRIVATE_KEY)
const msg = new SiweMessage({ domain: 'api.venice.ai', address:
wallet.address, statement: 'Sign in to Venice API', uri:
'https://api.venice.ai', version: '1', chainId: 8453, nonce:
crypto.randomUUID().replace(/-/g, '').slice(0, 16), issuedAt: new
Date().toISOString(), expirationTime: new Date(Date.now() +
600000).toISOString() })
const signature = await wallet.signMessage(msg.prepareMessage())
const header = btoa(JSON.stringify({ address: wallet.address, message:
msg.prepareMessage(), signature, timestamp: Date.now(), chainId: 8453
}))
// Set header: SIGN-IN-WITH-X:
```
**Solana message fields:** The signed message starts with `
wants you to sign in with your Solana account:`, followed by the wallet
address and the standard `URI`, `Version`, `Chain ID`, `Nonce`, `Issued
At`, and optional `Expiration Time` fields. Use `type: "ed25519"` and
`chainId: "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp"` in the encoded JSON
payload.
**SDK:** `npm install @venice-ai/x402-client` provides `VeniceClient`
and `createAuthFetch` which handle this automatically.
**Billing:** x402 users pay from a prepaid USDC credit balance. Top up
via `POST /x402/top-up`. When balance is insufficient, endpoints return
`402` with structured top-up instructions.
in: header
name: SIGN-IN-WITH-X
type: apiKey
````