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POST
/
generate
/
text
Generate text
curl --request POST \
  --url https://api.horizon.new/v1/generate/text \
  --header 'Content-Type: application/json' \
  --data '{
  "prompt": "<string>",
  "model": "sonnet",
  "maxTokens": 800,
  "temperature": 0.7,
  "metadata": {}
}'
{
  "jobId": "job_01hx9q9",
  "content": "<string>",
  "usage": {
    "promptTokens": 123,
    "completionTokens": 123,
    "totalTokens": 123
  }
}
Produce short- or long-form text with Horizon’s tuned language models. Use this endpoint for copywriting, summaries, or scripted dialog you plan to surface in apps, emails, or support workflows.

​
Request body

  • prompt — Required instructions or seed text.
  • model — Optional model identifier; defaults to the workspace text model (e.g., sonnet).
  • maxTokens — Optional upper bound for the completion length; defaults to 800.
  • temperature — Optional float between 0 and 1; higher values increase creativity.
  • metadata — Optional object that attaches custom keys for downstream auditing.

​
Sample request

curl https://api.horizon.new/v1/generate/text \
  -H "Content-Type: application/json" \
  -d '{
    "prompt": "Write a friendly welcome line for new Horizon users joining the platform.",
    "temperature": 0.2,
    "metadata": {
      "campaign": "spring-launch",
      "locale": "en-US"
    }
  }'

​
Response

Returns 200 OK with the generated text in result.content, token usage metrics under result.usage, and the deterministic jobId that you can reference in logs or attach to downstream automations.

​
Tips

  • Set temperature below 0.3 when you need repeatable copy for approval workflows.
  • If you need streaming output, append ?stream=true to the request and consume the server-sent events feed.
  • Even when responses return synchronously, you can retrieve the job later via GET /jobs/{jobId} for auditing or replay.

​
x402 flow

Text generation is priced via Coinbase’s x402 protocol. On unpaid requests Horizon returns 402 Payment Required with a PaymentRequiredResponse payload. Example: 
HTTP/1.1 402 Payment Required
Content-Type: application/json

{
  "x402Version": 1,
  "accepts": [
    {
      "scheme": "exact",
      "network": "base-sepolia",
      "maxAmountRequired": "50000",                // $0.05 in 6‑decimal USDC
      "resource": "POST /generate/text",
      "description": "Horizon text generation",
      "mimeType": "application/json",
      "payTo": "0xYourReceivingWallet",
      "maxTimeoutSeconds": 90,
      "asset": "0xYourUSDCContract",
      "extra": {
        "name": "USDC",
        "version": "1"
      }
    }
  ],
  "error": null
}
Resolve the challenge by following the Coinbase spec:
  1. Send the accepts entry to your facilitator as outlined in Client & server responsibilities.
  2. Use the facilitator to verify and settle the payment (POST /verify, POST /settle). You receive a Base64 Payment Payload.
  3. Retry the original request including the payload in an X-PAYMENT header: 
    curl https://api.horizon.new/v1/generate/text \
  -H "Content-Type: application/json" \
  -H "X-PAYMENT: eyJ4NDAyVmVyc2lvbiI6MSwic2NoZW1lIjoiZXhhY3QiLC4uLn0=" \
  -d '{ ...original body... }'
  4. Horizon validates the payment (locally or through the facilitator) and resumes processing. Successful responses can include X-PAYMENT-RESPONSE with the settlement receipt.
Need a refresher? Start with the Quickstart for sellers before rolling this endpoint to production.

Body

application/json
​
prompt
string
required
​
model
string
Example:

"sonnet"

​
maxTokens
integer
default:800
Required range: 1 <= x <= 4000
​
temperature
number
default:0.7
Required range: 0 <= x <= 1
​
metadata
object

Response

Generated text

​
jobId
string
required
Example:

"job_01hx9q9"

​
content
string
required
​
usage
object