HMAC Generator API Reference

Overview

Returns the HMAC signature in hex or base64 encoding. Use for signing API requests, validating webhooks, or any scenario requiring message authentication.

Endpoint

One host, one path per API. The block below shows this call in four languages; every one of them is the same HTTP request. Making requests covers the timeouts, retries and parameter rules that apply to all of them. The SDKs wrap the same call in a typed client.

POSThttps://api.apiverve.com/v1/hmac

curl -X POST https://api.apiverve.com/v1/hmac \
  -H "x-api-key: your_api_key_here" \
  -H "Content-Type: application/json" \
  -d '{
  "message": "Hello World",
  "secret": "my-secret-key",
  "algorithm": "sha256",
  "encoding": "hex"
}'

const res = await fetch('https://api.apiverve.com/v1/hmac', {
  method: 'POST',
  headers: {
    'x-api-key': 'your_api_key_here',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
  "message": "Hello World",
  "secret": "my-secret-key",
  "algorithm": "sha256",
  "encoding": "hex"
}),
});

if (!res.ok) throw new Error(`${res.status} ${await res.text()}`);

const { data } = await res.json();
console.log(data);

import requests

res = requests.post(
    "https://api.apiverve.com/v1/hmac",
    headers={"x-api-key": "your_api_key_here"},
    json={
    "message": "Hello World",
    "secret": "my-secret-key",
    "algorithm": "sha256",
    "encoding": "hex"
},
    timeout=15,
)
res.raise_for_status()

print(res.json()["data"])

package main

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

func main() {
	body := strings.NewReader(`{
  "message": "Hello World",
  "secret": "my-secret-key",
  "algorithm": "sha256",
  "encoding": "hex"
}`)
	req, _ := http.NewRequest("POST", "https://api.apiverve.com/v1/hmac", body)
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("x-api-key", "your_api_key_here")

	res, err := http.DefaultClient.Do(req)
	if err != nil {
		panic(err)
	}
	defer res.Body.Close()

	out, _ := io.ReadAll(res.Body)
	fmt.Println(string(out))
}

Replace your_api_key_here with the key from your dashboard. When the inputs arrive as a list rather than one at a time, batch requests run up to 200 of them through this same API in a single call.

Authentication

Send your key in the x-api-key header. That is the only auth step — there is no token exchange and no per-endpoint scope to configure. Authentication covers creating, rotating and revoking keys.

401 is the only auth verdict

A 401 means the key is missing, invalid or expired. A 403 means the key is valid but not permitted here — blocked by a key restriction or an IP allow-list. Running out of credits is a 429.

Parameters

Sent as JSON in the request body. Premium parameters are accepted on every plan but only take effect on plans that include them.

Parameter	Type	Description
`message`Required	string	The message to sign
`secret`Required	string	The secret key for HMAC generation
`algorithm`Optional	string	Hash algorithm to use `sha256sha384sha512sha1md5` default sha256
`encoding`Optional	string	Output encoding format `hexbase64` default hex

Response

Every API returns the same three top-level keys, so one response handler covers your whole integration: status, error and data. Only data changes shape. Response format covers the envelope, the other output formats and how premium fields are withheld.

Sample response

{
  "status": "ok",
  "error": null,
  "data": {
    "hmac": "2cd7c25025198d4458002ceb064ad37ccfbbe46650876d693f5e080bd954e449",
    "algorithm": "sha256",
    "encoding": "hex"
  }
}

Response fields

Paths are relative to data. Premium fields are absent rather than zeroed on plans that do not include them, so check for presence instead of comparing to 0.

Field	Type	Example	Description
`hmac`	string	`"2cd7c25025198d4458002ceb064ad37ccfbbe46650876d693f5e080bd954e449"`	Generated HMAC signature in specified encoding format
`algorithm`	string	`"sha256"`	Hash algorithm used for HMAC generation
`encoding`	string	`"hex"`	Output encoding format applied to the signature

Errors

Read the HTTP status first, then error for the specific reason. The body names the parameter that has to change. Error handling covers the full status list and which of them are worth retrying.

Status	Meaning	What to do
`400`	Input was rejected	Read `error`; it names the parameter.
`401`	Key missing or invalid	Check the header name and the key value.
`403`	Key valid, but not permitted	A key restriction or IP allow-list; see key scoping.
`429`	Rate limited, or out of credits	Read `error` to tell them apart; see rate limits.

Use cases

API Authentication: Sign API requests to prove authenticity
Webhook Verification: Validate incoming webhooks from services like Stripe, GitHub
Data Integrity: Ensure messages haven't been tampered with
JWT Signing: Generate signatures for JSON Web Tokens

Other ways to use HMAC Generator

Set up HMAC Generator on APIVerve, or reach the same source a different way. Your APIVerve account and credits work on all of them — one key, one balance.

Give it to an AI agentConnect over MCP and your agent calls it as a native tool — Claude, Cursor, ChatGPT.VerveKit →Reference →

HMAC Generator