REST API v1

ReplyBlade API

Generate strategic reply variants programmatically. Simple REST endpoint: send a message, get back crafted replies. No API key needed.

Endpoint

POST

/api/replies

Authentication

The API is completely free and open. No API key required. Just send a POST request to the endpoint with a JSON body.

Request Body

All fields must be sent as JSON.

Field	Type	Required	Default	Description
message	string	required	-	The incoming message you want replies for (1-8000 chars)
context	string	optional	""	Context about the sender or situation (up to 1000 chars)
goal	string	optional	""	Your desired outcome (up to 120 chars)
tone	number	optional	50	0 (warm) to 100 (firm)
count	number	optional	3	Number of variants: 1, 3, or 5
length	string	optional	"medium"	Reply length: 'short', 'medium', or 'long'
language	string	optional	""	Language for replies (empty = auto-detect)

Response

On success, returns a JSON object with a variants array.

{
  "variants": [
    {
      "label": "Polite Decline",
      "reply": "Hi [Name], thanks for the invite...",
      "strategy": "Optimizes for maintaining...",
      "tone": "Warm & polite",
      "risks": "May come across as evasive if..."
    }
  ]
}

On error, returns { "error": "..." } with appropriate HTTP status code (400, 429, 500).

Examples

curl

curl -X POST https://replyblade.com/api/replies \
  -H "Content-Type: application/json" \
  -d '{
    "message": "Can you join a call tomorrow at 2pm?",
    "context": "From my boss",
    "goal": "Politely decline",
    "tone": 50,
    "count": 3,
    "length": "medium"
  }'

python

import requests

response = requests.post(
    "https://replyblade.com/api/replies",
    headers={"Content-Type": "application/json"},
    json={
        "message": "Can you join a call tomorrow at 2pm?",
        "context": "From my boss",
        "goal": "Politely decline",
        "tone": 50,
        "count": 3,
        "length": "medium",
    },
)

data = response.json()
for variant in data["variants"]:
    print(f"[{variant['label']}] ({variant['tone']})")
    print(variant["reply"])
    print(f"Strategy: {variant['strategy']}")
    print(f"Risks: {variant['risks']}")
    print()

javascript

const response = await fetch("https://replyblade.com/api/replies", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    message: "Can you join a call tomorrow at 2pm?",
    context: "From my boss",
    goal: "Politely decline",
    tone: 50,
    count: 3,
    length: "medium",
  }),
});

const data = await response.json();
data.variants.forEach((v) => {
  console.log(`[${v.label}] (${v.tone})`);
  console.log(v.reply);
  console.log("Strategy:", v.strategy);
  console.log("Risks:", v.risks);
});

Try it yourself

Test the endpoint live. No API key needed.

Message

Context

Goal

Tone (0-100)

Count

Length

Rate Limits

API requests are rate-limited to 3 requests per minute and 10 requests per hour per IP address. If you exceed either limit, you'll receive a 429 response. This is the same rate limit applied to the web UI (including screenshot reads).

Error Codes

Code	Meaning
400	Invalid request body or validation failed
405	Method not allowed (use POST)
429	Rate limited (3/min, 10/hour per IP)
500	Internal server error