Developer API · v1

ReplyWithCare API

Generate review responses from your own app, a Chrome extension, a CRM workflow, or anywhere else you can make an HTTPS request. Bearer-token auth, JSON in, JSON out. No SDK required.

Agency planAPI access is included on Agency. Email hello@replywithcare.com to enable it.

Quick start

Create a ReplyWithCare account if you don't have one.
Email hello@replywithcare.com to be added to the Agency plan (API access lives there).
Once we confirm, go to Dashboard → API Keys and click Generate key. Copy the key immediately — we only show it once.
Send a POST request to the endpoint below.

Endpoint

POSThttps://replywithcare.com/api/v1/generate

All API requests must use HTTPS. Plain HTTP requests are rejected by Vercel before they reach the function.

Authentication

Send your API key in the Authorization header as a Bearer token. Keys look like rwc_live_… and are tied to your account.

HTTP header

Authorization: Bearer rwc_live_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Never embed your key in client-side code that ships to end users (a public website or a published mobile app). For Chrome extensions, store the key in chrome.storage.local after the user pastes it into your extension's settings.

Request body

JSON with the following fields:

Field	Type	Description
review	string	Required. Review text. 5-2000 characters.
tone	string	Optional. One of `professional`, `friendly`, `apologetic`, `grateful`. Default `professional`.
language	string	Optional. `auto` (detect from review) or a BCP-47 code like `en`, `hi`, `es`. Default `auto`.
length	string	Optional. `short` (~50w), `medium` (~100w), `long` (~150w). Pro-only; free-tier keys always receive medium.

Response

200 OK

{
  "reply": "Thank you so much for the kind words, Maya — we're delighted...",
  "model": "gemini-2.5-flash",
  "requestId": "8b3c12d4-..."
}

requestId is unique per request. Include it in any support ticket so we can look up the call in our logs.

Official SDK

Type-safe TypeScript wrapper with built-in retry-on-429 and typed errors. Zero runtime dependencies, works in Node 18+ and modern browsers (Chrome extensions included).

install

npm i @replywithcare/sdk

typescript

import { ReplyWithCare, ReplyWithCareError } from '@replywithcare/sdk';

const client = new ReplyWithCare({
  apiKey: process.env.RWC_API_KEY!,
});

try {
  const { reply, requestId } = await client.generate({
    review: 'Loved the service! Coffee was perfect.',
    tone: 'grateful',
    language: 'en',
  });
  console.log(reply);
} catch (err) {
  if (err instanceof ReplyWithCareError) {
    if (err.code === 'rate_limited') {
      // SDK auto-retries 429s up to 3 times — if this fires the
      // backoff window was exhausted. Slow down upstream.
    }
    console.error(err.code, err.message, err.requestId);
  }
}

See the SDK README for the full options table, error codes, and Chrome-extension example.

Raw HTTP examples

curl

bash

curl -X POST https://replywithcare.com/api/v1/generate \
  -H "Authorization: Bearer rwc_live_xxxxxxxx" \
  -H "Content-Type: application/json" \
  -d '{
    "review": "Great service! The team was so helpful and the coffee was perfect.",
    "tone": "grateful",
    "language": "en",
    "length": "medium"
  }'

JavaScript (fetch)

javascript

const res = await fetch('https://replywithcare.com/api/v1/generate', {
  method: 'POST',
  headers: {
    'Authorization': `Bearer ${process.env.RWC_API_KEY}`,
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    review: 'Great service! The team was so helpful and the coffee was perfect.',
    tone: 'grateful',
    language: 'en',
  }),
});

if (!res.ok) {
  const err = await res.json();
  throw new Error(`${err.error}: ${err.message}`);
}

const { reply, requestId } = await res.json();
console.log(reply);

Python (requests)

python

import os, requests

resp = requests.post(
    "https://replywithcare.com/api/v1/generate",
    headers={"Authorization": f"Bearer {os.environ['RWC_API_KEY']}"},
    json={
        "review": "Great service! The team was so helpful and the coffee was perfect.",
        "tone": "grateful",
        "language": "en",
    },
    timeout=30,
)
resp.raise_for_status()
print(resp.json()["reply"])

Errors

Errors return a JSON body with a machine-readable error code and a human-readable message.

Status	error code	Meaning
400	invalid_review	Review is missing, empty, or out of length bounds (5-2000).
400	invalid_tone	Tone is not one of the allowed values.
400	invalid_json	Body could not be parsed as JSON.
401	missing_authorization	No Bearer token in the Authorization header.
401	invalid_api_key	Key not found or revoked.
403	agency_required	Key is valid but the owner's subscription is not on the Agency tier. Contact sales to upgrade.
429	rate_limited	Too many requests in the last minute. Limit is 15 requests per minute per API key. Response includes a `Retry-After` header (seconds) and `X-RateLimit-*` headers.
429	daily_limit_reached	Account's monthly generation quota is exhausted (3,000/mo on Agency). Resets on the 1st (UTC).
500	generation_failed	Upstream LLM failure. Retry with backoff.

Quota

Agency accounts get 3,000 generations per month, shared across the in-app generator and the public API. Quota resets on the 1st of each month (UTC). If you need a higher ceiling, email hello@replywithcare.com for a custom plan.

Rate limit

Each API key is capped at 15 requests per minute to keep a leaked or runaway key from burning the entire monthly quota in seconds. Requests over the cap return 429 rate_limited with these headers:

response headers

Retry-After: <seconds until window resets>
X-RateLimit-Limit: 15
X-RateLimit-Remaining: <calls left in this minute>

Honor Retry-After with exponential backoff if you batch — most SDKs (axios, ky, ofetch, requests) have a retry-with-backoff helper built in.

CORS

The endpoint sets Access-Control-Allow-Origin: * so Chrome extensions and third-party web apps can call it directly from the browser. Auth is enforced entirely by the Bearer token — never expose the key to untrusted code.

Ready to integrate?

Generate your first key in the dashboard. Takes ten seconds.

Get an API key