Chat completions (ZeroClick)

Create a chat completion (ZeroClick-authenticated)

curl --request POST \
  --url https://api.zerogpu.ai/zeroclick/v1/chat/completions \
  --header 'Content-Type: application/json' \
  --header 'zc-signature: <api-key>' \
  --data '
{
  "model": "LFM2.5-1.2B-Instruct",
  "messages": [
    {
      "role": "user",
      "content": "Summarize the following article: ..."
    }
  ]
}
'

import requests

url = "https://api.zerogpu.ai/zeroclick/v1/chat/completions"

payload = {
    "model": "LFM2.5-1.2B-Instruct",
    "messages": [
        {
            "role": "user",
            "content": "Summarize the following article: ..."
        }
    ]
}
headers = {
    "zc-signature": "<api-key>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {'zc-signature': '<api-key>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    model: 'LFM2.5-1.2B-Instruct',
    messages: [{role: 'user', content: 'Summarize the following article: ...'}]
  })
};

fetch('https://api.zerogpu.ai/zeroclick/v1/chat/completions', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

false

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.zerogpu.ai/zeroclick/v1/chat/completions"

	payload := strings.NewReader("{\n  \"model\": \"LFM2.5-1.2B-Instruct\",\n  \"messages\": [\n    {\n      \"role\": \"user\",\n      \"content\": \"Summarize the following article: ...\"\n    }\n  ]\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("zc-signature", "<api-key>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

require 'uri'
require 'net/http'

url = URI("https://api.zerogpu.ai/zeroclick/v1/chat/completions")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["zc-signature"] = '<api-key>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"model\": \"LFM2.5-1.2B-Instruct\",\n  \"messages\": [\n    {\n      \"role\": \"user\",\n      \"content\": \"Summarize the following article: ...\"\n    }\n  ]\n}"

response = http.request(request)
puts response.read_body

{
  "id": "<string>",
  "object": "<string>",
  "created": 123,
  "model": "<string>",
  "choices": [
    {
      "index": 123,
      "finish_reason": "<string>",
      "message": {
        "role": "<string>",
        "content": "<string>",
        "annotations": [
          "<unknown>"
        ]
      }
    }
  ],
  "usage": {
    "prompt_tokens": 123,
    "completion_tokens": 123,
    "total_tokens": 123,
    "prompt_tokens_details": {},
    "completion_tokens_details": {}
  }
}

POST

zeroclick

chat

completions

Create a chat completion (ZeroClick-authenticated)

curl --request POST \
  --url https://api.zerogpu.ai/zeroclick/v1/chat/completions \
  --header 'Content-Type: application/json' \
  --header 'zc-signature: <api-key>' \
  --data '
{
  "model": "LFM2.5-1.2B-Instruct",
  "messages": [
    {
      "role": "user",
      "content": "Summarize the following article: ..."
    }
  ]
}
'

import requests

url = "https://api.zerogpu.ai/zeroclick/v1/chat/completions"

payload = {
    "model": "LFM2.5-1.2B-Instruct",
    "messages": [
        {
            "role": "user",
            "content": "Summarize the following article: ..."
        }
    ]
}
headers = {
    "zc-signature": "<api-key>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {'zc-signature': '<api-key>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    model: 'LFM2.5-1.2B-Instruct',
    messages: [{role: 'user', content: 'Summarize the following article: ...'}]
  })
};

fetch('https://api.zerogpu.ai/zeroclick/v1/chat/completions', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

false

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.zerogpu.ai/zeroclick/v1/chat/completions"

	payload := strings.NewReader("{\n  \"model\": \"LFM2.5-1.2B-Instruct\",\n  \"messages\": [\n    {\n      \"role\": \"user\",\n      \"content\": \"Summarize the following article: ...\"\n    }\n  ]\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("zc-signature", "<api-key>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

require 'uri'
require 'net/http'

url = URI("https://api.zerogpu.ai/zeroclick/v1/chat/completions")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["zc-signature"] = '<api-key>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"model\": \"LFM2.5-1.2B-Instruct\",\n  \"messages\": [\n    {\n      \"role\": \"user\",\n      \"content\": \"Summarize the following article: ...\"\n    }\n  ]\n}"

response = http.request(request)
puts response.read_body

{
  "id": "<string>",
  "object": "<string>",
  "created": 123,
  "model": "<string>",
  "choices": [
    {
      "index": 123,
      "finish_reason": "<string>",
      "message": {
        "role": "<string>",
        "content": "<string>",
        "annotations": [
          "<unknown>"
        ]
      }
    }
  ],
  "usage": {
    "prompt_tokens": 123,
    "completion_tokens": 123,
    "total_tokens": 123,
    "prompt_tokens_details": {},
    "completion_tokens_details": {}
  }
}

This is the Chat completions endpoint behind ZeroClick, ZeroGPU’s agent-payment layer. Same request/response bodies and same model routing as /v1/chat/completions — only authentication, authorization, and metering differ.

Authentication — no x-api-key. A buying agent calls ZeroClick’s hosted pay URL; ZeroClick proxies the request and signs the raw request bytes with an HMAC in the zc-signature header. A request is authenticated only by a valid signature.
Authorization — a ZeroClick allowance check runs before any billable work. It fails open on a transient ZeroClick outage (the signature has already verified), but never for a missing or invalid signature.
Metering — actual token usage is settled with ZeroClick and reported via the zc-usage response header. Stripe metering is bypassed; ZeroClick is the sole biller.

Response JSON shape depends on the model; handle errors the same way as API error codes.

Authorizations

zc-signature

string

header

required

HMAC signature minted by ZeroClick over the raw request bytes, of the form t=<unix-seconds>,kid=<key-id>,v1=<hex-hmac>. Verified by the @zeroclickai/sellers SDK against the seller's signing secret keyed by kid. A missing or invalid signature is rejected with 401 invalid_zeroclick_signature; this is never failed open.

Headers

zc-request-id

string

ZeroClick request id, echoed in logs for correlation. Set by ZeroClick when it proxies the request.

Example:

"zcreq_1"

zc-agent-id

string

Identifier of the buying agent. Used to partition logs/analytics by agent; becomes the synthesized caller identity.

Example:

"agt_1"

Body

application/json

model

string

required

Model id; routes the request via model metadata. Kebab-cased into a ZeroClick service slug for metering.

Example:

"LFM2.5-1.2B-Instruct"

messages

object[]

required

Minimum array length: 1

Hide child attributes

messages.role

enum<string>

required

A developer role is normalized to system; unrecognized roles are treated as user.

Available options:

system,

user,

assistant,

tool,

developer

messages.content

string

required

Response

OpenAI Chat Completions response. Includes the zc-usage header settling actual usage with ZeroClick.

OpenAI Chat Completions response. For classification models, choices[0].message.content is a JSON-stringified classification result.

string

object

string

Allowed value: "chat.completion"

created

integer

model

string

choices

object[]

Hide child attributes

choices.index

integer

choices.finish_reason

string

choices.message

object

Hide child attributes

choices.message.role

string

Allowed value: "assistant"

choices.message.content

string

choices.message.annotations

any[]

usage

object

Hide child attributes

usage.prompt_tokens

integer

usage.completion_tokens

integer

usage.total_tokens

integer

usage.prompt_tokens_details

object

usage.completion_tokens_details

object

Responses Upload file

⌘I

Endpoints

ZeroClick

Batch API

Chat completions (ZeroClick)

Authorizations

Headers

Body

Response