Suggest a mail class for a draft
curl --request POST \
--url https://sendpaperplane.com/v1/suggest-class \
--header 'Content-Type: application/json' \
--data '
{
"text": "This letter serves as formal notice that your lease will not be renewed."
}
'import requests
url = "https://sendpaperplane.com/v1/suggest-class"
payload = { "text": "This letter serves as formal notice that your lease will not be renewed." }
headers = {"Content-Type": "application/json"}
response = requests.post(url, json=payload, headers=headers)
print(response.text)const options = {
method: 'POST',
headers: {'Content-Type': 'application/json'},
body: JSON.stringify({
text: 'This letter serves as formal notice that your lease will not be renewed.'
})
};
fetch('https://sendpaperplane.com/v1/suggest-class', options)
.then(res => res.json())
.then(res => console.log(res))
.catch(err => console.error(err));const options = {
method: 'POST',
headers: {'Content-Type': 'application/json'},
body: JSON.stringify({
text: 'This letter serves as formal notice that your lease will not be renewed.'
})
};
fetch('https://sendpaperplane.com/v1/suggest-class', options)
.then(res => res.json())
.then(res => console.log(res))
.catch(err => console.error(err));package main
import (
"fmt"
"strings"
"net/http"
"io"
)
func main() {
url := "https://sendpaperplane.com/v1/suggest-class"
payload := strings.NewReader("{\n \"text\": \"This letter serves as formal notice that your lease will not be renewed.\"\n}")
req, _ := http.NewRequest("POST", url, payload)
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://sendpaperplane.com/v1/suggest-class")
http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true
request = Net::HTTP::Post.new(url)
request["Content-Type"] = 'application/json'
request.body = "{\n \"text\": \"This letter serves as formal notice that your lease will not be renewed.\"\n}"
response = http.request(request)
puts response.read_body<?php
$curl = curl_init();
curl_setopt_array($curl, [
CURLOPT_URL => "https://sendpaperplane.com/v1/suggest-class",
CURLOPT_RETURNTRANSFER => true,
CURLOPT_ENCODING => "",
CURLOPT_MAXREDIRS => 10,
CURLOPT_TIMEOUT => 30,
CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
CURLOPT_CUSTOMREQUEST => "POST",
CURLOPT_POSTFIELDS => json_encode([
'text' => 'This letter serves as formal notice that your lease will not be renewed.'
]),
CURLOPT_HTTPHEADER => [
"Content-Type: application/json"
],
]);
$response = curl_exec($curl);
$err = curl_error($curl);
curl_close($curl);
if ($err) {
echo "cURL Error #:" . $err;
} else {
echo $response;
}HttpResponse<String> response = Unirest.post("https://sendpaperplane.com/v1/suggest-class")
.header("Content-Type", "application/json")
.body("{\n \"text\": \"This letter serves as formal notice that your lease will not be renewed.\"\n}")
.asString();{
"status": "ok",
"suggested_class": "certified",
"reason": "This reads as a formal legal notice, where proof of delivery matters.",
"source": "heuristic"
}{
"status": "failed",
"code": "<string>",
"reason": "<string>",
"next": [
"<string>"
]
}{
"status": "failed",
"code": "<string>",
"reason": "<string>",
"next": [
"<string>"
]
}Suggest a mail class for a draft
Advisory only, never authoritative — the sender always picks. LLM-backed when ANTHROPIC_API_KEY is set, word-bounded heuristic otherwise.
POST
/
v1
/
suggest-class
Suggest a mail class for a draft
curl --request POST \
--url https://sendpaperplane.com/v1/suggest-class \
--header 'Content-Type: application/json' \
--data '
{
"text": "This letter serves as formal notice that your lease will not be renewed."
}
'import requests
url = "https://sendpaperplane.com/v1/suggest-class"
payload = { "text": "This letter serves as formal notice that your lease will not be renewed." }
headers = {"Content-Type": "application/json"}
response = requests.post(url, json=payload, headers=headers)
print(response.text)const options = {
method: 'POST',
headers: {'Content-Type': 'application/json'},
body: JSON.stringify({
text: 'This letter serves as formal notice that your lease will not be renewed.'
})
};
fetch('https://sendpaperplane.com/v1/suggest-class', options)
.then(res => res.json())
.then(res => console.log(res))
.catch(err => console.error(err));const options = {
method: 'POST',
headers: {'Content-Type': 'application/json'},
body: JSON.stringify({
text: 'This letter serves as formal notice that your lease will not be renewed.'
})
};
fetch('https://sendpaperplane.com/v1/suggest-class', options)
.then(res => res.json())
.then(res => console.log(res))
.catch(err => console.error(err));package main
import (
"fmt"
"strings"
"net/http"
"io"
)
func main() {
url := "https://sendpaperplane.com/v1/suggest-class"
payload := strings.NewReader("{\n \"text\": \"This letter serves as formal notice that your lease will not be renewed.\"\n}")
req, _ := http.NewRequest("POST", url, payload)
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://sendpaperplane.com/v1/suggest-class")
http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true
request = Net::HTTP::Post.new(url)
request["Content-Type"] = 'application/json'
request.body = "{\n \"text\": \"This letter serves as formal notice that your lease will not be renewed.\"\n}"
response = http.request(request)
puts response.read_body<?php
$curl = curl_init();
curl_setopt_array($curl, [
CURLOPT_URL => "https://sendpaperplane.com/v1/suggest-class",
CURLOPT_RETURNTRANSFER => true,
CURLOPT_ENCODING => "",
CURLOPT_MAXREDIRS => 10,
CURLOPT_TIMEOUT => 30,
CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
CURLOPT_CUSTOMREQUEST => "POST",
CURLOPT_POSTFIELDS => json_encode([
'text' => 'This letter serves as formal notice that your lease will not be renewed.'
]),
CURLOPT_HTTPHEADER => [
"Content-Type: application/json"
],
]);
$response = curl_exec($curl);
$err = curl_error($curl);
curl_close($curl);
if ($err) {
echo "cURL Error #:" . $err;
} else {
echo $response;
}HttpResponse<String> response = Unirest.post("https://sendpaperplane.com/v1/suggest-class")
.header("Content-Type", "application/json")
.body("{\n \"text\": \"This letter serves as formal notice that your lease will not be renewed.\"\n}")
.asString();{
"status": "ok",
"suggested_class": "certified",
"reason": "This reads as a formal legal notice, where proof of delivery matters.",
"source": "heuristic"
}{
"status": "failed",
"code": "<string>",
"reason": "<string>",
"next": [
"<string>"
]
}{
"status": "failed",
"code": "<string>",
"reason": "<string>",
"next": [
"<string>"
]
}Body
application/json
Required string length:
1 - 50000Last modified on September 17, 2026
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