The API gateway for AI agents

One API gateway
for AI agents.

Give agents one unified way to discover, authenticate, and call 90+ APIs so developers can ship faster with less integration overhead.

Get Started Browse APIs

90+

APIs available

API key needed

<2 min

Setup time

99.9%

Uptime SLA

Works with

Claude

Cursor

Antigravity

|View all integrations →

How it works

Three steps. That's it.

Connect once

Get one Callio key and connect to the entire gateway instead of setting up every API separately.

Discover APIs

Browse available APIs or let your agent find the right one. Callio handles discovery, auth, and routing.

Execute & ship

Call any API through one unified interface. Your team spends less time on plumbing and more time shipping.

Simple to integrate

One key and one interface for the APIs your agents need, without the usual auth work and custom integrations.

Works with any language or framework

One unified proxy — just change the slug

Bring your own provider keys (BYOK)

# 1. Install the SDK

npm install callio-sdk

# 2. Initialize with your single Callio key

import { CallioClient } from 'callio-sdk';

const callio = new CallioClient('callio_your_api_key');

# 3. Call ANY API through the unified proxy

/* OpenAI */

await callio.post('openai', 'v1/chat/completions', {

model: 'gpt-4',

messages: [{ role: 'user', content: 'Hi!' }]

});

/* Same key, different API - just change the slug! */

await callio.post('sendgrid', 'v3/mail/send', {

to: 'user@co.com', subject: 'Hello'

});

Built with Security

Your credentials, your control

Provider keys are AES-256 encrypted at rest. Callio keys are hashed. We never store request or response data.

Encrypted at rest

All provider credentials are AES-256-GCM encrypted before storage.

Zero data logging

Request and response bodies pass through — we only log metadata.

Built-in rate limits

Per-plan quotas and real-time usage monitoring from your dashboard.

MCP Server

Connect Antigravity, Cursor & more

Install the MCP server and your AI agent gets instant access to 90+ APIs through the same unified gateway.

Antigravity→MCP Settings panel

Cursor→.cursor/mcp.json

Claude Code→~/.claude/claude_desktop_config.json

Setup guide View source

mcp config

{

"mcpServers": {

"callio": {

"command": "npx",

"args": ["-y", "github:hmadhsan/callio-mcp"],

"env": {

"CALLIO_API_KEY": "callio_your_key"

}

APIs for everything

Search, payments, AI, scraping, messaging, and more through one gateway for agents.

Web, news, products

Send, verify, find

Data

Enrich, scrape, extract

Messaging

SMS, chat, notifications

Analytics

Tracking, insights

Cloud

AWS, GCP, Azure

Identity

Auth, KYC, verify

Social

LinkedIn, X, Instagram

AI / ML

Models, embeddings

Dev Tools

GitHub, CI/CD, logs

Storage

Files, S3, CDN

And many more. New APIs added every week.

Built for

Whether you build agents or provide APIs — Callio is for you.

AI developers

Give your agents real-world capabilities without stitching together dozens of integrations yourself.

API providers

List your API on Callio and get distribution into the growing ecosystem of AI agents and agentic products.

Startups

Ship faster by skipping auth, routing, and API plumbing. Focus your team on product, not infrastructure glue.

Frequently asked questions

What is Callio?

Callio is the API gateway for AI agents. It gives developers one interface to discover, authenticate, and call 90+ APIs.

How is this different from just calling APIs directly?

Instead of wiring up separate APIs one by one, you use one gateway. Callio handles auth, routing, and integration overhead for you.

Who is Callio for?

AI developers building agent workflows, API providers wanting distribution to AI agents, and startups that need to ship fast without infrastructure overhead.

How much does it cost to get started?

Our Starter plan is just $5/month and includes enough API requests and keys to build and test your integration.

Can I add my own API to Callio?

Absolutely. API providers can list their APIs on Callio and get instant distribution to thousands of AI agents. Book a demo to learn more.

Get in touch

Have questions, feedback, or want to list your API? We'd love to hear from you.

One API gateway for AI agents.