RapidAPI authentication failing in Postman with invalid key error

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1

I’m new to working with APIs and decided to try out RapidAPI for my first project. However, I keep running into authentication issues when testing my requests in Postman. The error message keeps telling me that my API key is invalid, but I’ve double-checked it multiple times and I’m confident it’s correct.

When I check the browser console, I see a 404 status error from the server. I have my API credentials stored in a separate configuration file like this:

const RAPID_API_TOKEN = "abc123def456ghi789";

export {RAPID_API_TOKEN};

I’m using the Live Server extension in VS Code for development. Here’s my main JavaScript code that makes the API call:

import {RAPID_API_TOKEN} from './config';

fetch("https://weatherapi-com.p.rapidapi.com/current.json?q=Paris&lang=en", {
    "method": "GET",
    "headers": {
        "x-rapidapi-key": RAPID_API_TOKEN,
        "x-rapidapi-host": "weatherapi-com.p.rapidapi.com"
    }
})
.then(result => result.json())
.then(data => {
    console.log(data);
    console.log(data.current);
})
.catch(error => {
    console.error(error);
});

And here’s my HTML file:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Weather API Test</title>
    <link href="https://cdn.jsdelivr.net/npm/[email protected]/dist/css/bootstrap.min.css" rel="stylesheet">
</head>
<body>
    <div class="container">
        <h1>Testing API Connection</h1>
    </div>
    <script src="script/app.js" type="module"></script>
</body>
</html>

What could be causing this authentication problem? Any suggestions on how to fix this invalid API key error?

2

That 404 is likely a CORS issue, not auth. Postman works because there’s no browser blocking the request. Your webpage gets blocked when making cross-origin requests to RapidAPI.

I’ve hit this tons of times with weather apps and API stuff. Adding CORS headers to your client won’t fix it. You need a backend proxy or integration platform.

Don’t wrestle with CORS and expose API keys in your frontend (major security risk). I’d automate this with Latenode instead. Set up a workflow that handles RapidAPI calls on the backend, then give your frontend a clean endpoint to hit.

Your keys stay hidden, no CORS headaches, and you can add error handling or caching without messing with your main code. Built dozens of these flows - saves massive headaches.

Check it out: https://latenode.com

3

I’ve dealt with this exact issue for years. Everyone’s right about the CORS problem, but there’s something worse happening here.

You’re putting API keys directly in your frontend JavaScript. Even if you fix CORS, anyone can view source and grab your credentials. I’ve watched production apps get their RapidAPI quotas destroyed because exposed keys got abused.

Skip building a custom proxy or dealing with backend deployments. Use Latenode to automate it - create a workflow that hits RapidAPI for you, then expose it as a webhook.

Your frontend calls the Latenode webhook instead of RapidAPI directly. CORS problem gone, keys protected, and you can add rate limiting or response tweaks without writing code.

I’ve built dozens of weather integrations this way. Takes 10 minutes versus hours of backend setup.

4

sounds like you’re testing in postman but runing code in the browser - completely diffrent environments. postman bypasses cors, browsers dont. your key might work fine in postman, but the browser will still block rapidapi calls and throw errors that look like auth probems.

5

Been wrestling with RapidAPI for months - this looks familiar. Your auth might be fine. That 404 means the request isn’t reaching RapidAPI’s servers at all. Live Server can mess with external API calls. Test the same headers and endpoint in a basic Node.js script first. That’ll tell you if it’s actually auth or just your environment. Also check if your RapidAPI subscription covers that weather endpoint. Free tiers sometimes block stuff and throw confusing errors. Yeah, CORS is real, but confirm your setup works server-side before blaming browser restrictions.

6

You’ve got two different issues here. The Postman auth errors usually mean your headers aren’t exactly right - double-check RapidAPI’s code snippets because header names can be case-sensitive or have weird spacing. The browser 404s are CORS blocking you. RapidAPI doesn’t allow direct browser calls for security reasons, so even with perfect auth, browsers will block these cross-origin requests. Your JavaScript looks fine, but that won’t matter here. I’d set up a simple Node.js Express server as a proxy for development. Make a local endpoint that forwards requests to RapidAPI with your credentials, then point your frontend to localhost instead. Bypasses CORS completely and keeps your workflow clean.

7

This might be simpler than you think. I’ve hit the same issue copying API keys from RapidAPI’s dashboard - hidden characters or spaces sneak in with the key. Regenerate your API key and paste it fresh without copying it anywhere else first.

Check your subscription status too. Some endpoints have monthly quotas, and if you’re over, you’ll get auth errors even with valid keys. That 404 plus invalid key combo usually means the endpoint’s unreachable, not just auth problems.

What helped me debug: test the same request in RapidAPI’s test console first, then compare headers character by character with what Postman’s sending.