Recommended endpoint
Minimal request
{
"model": "claude-sonnet-4-20250514",
"max_tokens": 1024,
"messages": [
{
"role": "user",
"content": [
{
"type": "image",
"source": {
"type": "url",
"url": "https://example.com/ui.png"
}
},
{ "type": "text", "text": "Describe the UI structure in this screenshot." }
]
}
]
}
cURL example
curl https://api.anthropic.com/v1/messages \
-H "x-api-key: $ANTHROPIC_API_KEY" \
-H "anthropic-version: 2023-06-01" \
-H "content-type: application/json" \
-d '{
"model": "claude-sonnet-4-20250514",
"max_tokens": 1024,
"messages": [
{
"role": "user",
"content": [
{
"type": "image",
"source": {
"type": "url",
"url": "https://example.com/ui.png"
}
},
{ "type": "text", "text": "Describe the UI structure in this screenshot." }
]
}
]
}'
Python example
from anthropic import Anthropic
client = Anthropic(api_key="<ANTHROPIC_API_KEY>")
response = client.messages.create(
model="claude-sonnet-4-20250514",
max_tokens=1024,
messages=[
{
"role": "user",
"content": [
{
"type": "image",
"source": {
"type": "url",
"url": "https://example.com/ui.png",
},
},
{"type": "text", "text": "Describe the UI structure in this screenshot."},
],
}
],
)
print(response.content[0].text)
Node.js example
import Anthropic from "@anthropic-ai/sdk";
const client = new Anthropic({
apiKey: process.env.ANTHROPIC_API_KEY,
});
const response = await client.messages.create({
model: "claude-sonnet-4-20250514",
max_tokens: 1024,
messages: [
{
role: "user",
content: [
{
type: "image",
source: {
type: "url",
url: "https://example.com/ui.png"
}
},
{ type: "text", text: "Describe the UI structure in this screenshot." }
]
}
]
});
console.log(response.content[0].text);
Best practices
- Put the image block before the instruction in most vision prompts
- Use Files API for large or repeated inputs
- Claude works especially well for OCR, UI understanding, and moderation-style vision tasks