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WP EngineDocumentation

Generate image metadata

POST
/v1/images/alt-text
<?php
$client = new \GuzzleHttp\Client();
$response = $client->request('POST', 'https://api.ai.wpengine.com/v1/images/alt-text', [
'body' => '{ "model": "google/gemini-3.5-flash", "image": "example", "mime_type": "image/png", "context": "example" }',
'headers' => [
'Authorization' => 'Bearer <token>',
'Content-Type' => 'application/json',
],
]);
echo $response->getBody();

Accepts a base64-encoded image and returns AI-generated metadata including alt-text, title, caption, and description suitable for WordPress media library entries. Maximum image size is 20 MiB. Requires a valid WP Engine bearer token; API keys must carry the “image:write” permission.

Media typeapplication/json
object
model

Optional model identifier. Defaults to a Gemini vision model when omitted.

string
Example
google/gemini-3.5-flash
image
required

Base64-encoded image data. The decoded image must not exceed 20 MiB.

string
mime_type

MIME type of the image (e.g. “image/png”, “image/jpeg”). Defaults to “image/png”.

string
default: image/png
context

Optional context describing how the metadata should be produced. For example, “this is a product photo for an e-commerce site, focus on the product details”.

string

Generated image metadata

Media typeapplication/json
object
alt_text
required

The generated alt-text for the image.

string
title

A short, descriptive title for the image.

string
caption

A brief caption suitable for display below the image.

string
description

A detailed description of the image.

string
model

The model used for generation.

string
Examplegenerated
{
"alt_text": "example",
"title": "example",
"caption": "example",
"description": "example",
"model": "example"
}

Invalid request body or parameters

Media typeapplication/json
object
error
required
object
message
required
string
type
required
string
code
required
integer
request_id
required

Correlation ID for this request, matching the X-Request-ID response header — a 32-character trace ID behind the load balancer, otherwise a UUID. Quote it in support reports.

string
Example
{
"error": {
"type": "invalid_request_error",
"request_id": "80f1e2c3a4b5c6d7e8f9a0b1c2d3e4f5"
}
}

Missing or invalid bearer token

Media typeapplication/json
object
error
required
object
message
required
string
type
required
string
code
required
integer
request_id
required

Correlation ID for this request, matching the X-Request-ID response header — a 32-character trace ID behind the load balancer, otherwise a UUID. Quote it in support reports.

string
Example
{
"error": {
"type": "invalid_request_error",
"request_id": "80f1e2c3a4b5c6d7e8f9a0b1c2d3e4f5"
}
}
WWW-Authenticate
string
Example
Bearer realm="ai-services"

The account’s credit balance is exhausted. Grant or top up credits before retrying. Distinct from 429, which is edge rate limiting.

Media typeapplication/json
object
error
required
object
message
required
string
type
required
string
code
required
integer
request_id
required

Correlation ID for this request, matching the X-Request-ID response header — a 32-character trace ID behind the load balancer, otherwise a UUID. Quote it in support reports.

string
Example
{
"error": {
"type": "invalid_request_error",
"request_id": "80f1e2c3a4b5c6d7e8f9a0b1c2d3e4f5"
}
}

The token is valid, but the caller is not permitted to perform this action — either its scope/permission is insufficient or the authenticated user is not authorized for the target account (error type “permission_error”). On /v1/chat/completions specifically, a 403 with error type “content_policy_violation” instead means the request content was blocked by content moderation policy; that response never identifies which filter or category matched.

Media typeapplication/json
object
error
required
object
message
required
string
type
required
string
code
required
integer
request_id
required

Correlation ID for this request, matching the X-Request-ID response header — a 32-character trace ID behind the load balancer, otherwise a UUID. Quote it in support reports.

string
Example
{
"error": {
"type": "invalid_request_error",
"request_id": "80f1e2c3a4b5c6d7e8f9a0b1c2d3e4f5"
}
}

Rate limit exceeded. The request was throttled at the edge; wait and retry later. The response body is a short HTML page generated by the load balancer, not a structured JSON error — clients should rely on the 429 status code rather than parsing the body.

Media typetext/html
string

Upstream provider returned an error

Media typeapplication/json
object
error
required
object
message
required
string
type
required
string
code
required
integer
request_id
required

Correlation ID for this request, matching the X-Request-ID response header — a 32-character trace ID behind the load balancer, otherwise a UUID. Quote it in support reports.

string
Example
{
"error": {
"type": "invalid_request_error",
"request_id": "80f1e2c3a4b5c6d7e8f9a0b1c2d3e4f5"
}
}

A required dependency is temporarily unavailable. Retry after a short delay with exponential back-off.

Media typeapplication/json
object
error
required
object
message
required
string
type
required
string
code
required
integer
request_id
required

Correlation ID for this request, matching the X-Request-ID response header — a 32-character trace ID behind the load balancer, otherwise a UUID. Quote it in support reports.

string
Example
{
"error": {
"type": "invalid_request_error",
"request_id": "80f1e2c3a4b5c6d7e8f9a0b1c2d3e4f5"
}
}