Instant Messaging API and SDK 2025

Real-time chats or instant messaging, call it either way are becoming the most looked-after capabilities of this gen's modern communication because they allow you to quickly chat with your friends, coordinate with your peers, and engage with your customers immediately. Therefore, businesses are building chat applications from scratch or using instant messaging APIs to ease the building process or add a specific feature to their existing software.

But the point here is to choose the right instant messaging SDK, as it can make or break your experience. So, how do you pick the apt one? Worry less as we have done the heavy lifting by bringing in top chat APIs and SDKs of 2025, along with their features, pricing, and more.

What is an Instant Messaging API & SDK?

Both Instant Messaging APIs and SDKs allow developers or brands to add pre-built chat features like single chats, group chats, push notifications, and others into existing apps and websites. They use pre-built messaging attributes as it helps businesses reduce development costs and saves time from building a solution from level zero.

And though APIs and SDKs work together, they are not the same. An API is just an interface that allows one app to interact with another. This means it provides back-end services, making it easy to integrate real-time features. Plus, APIs can be used independently or with an SDK.

An SDK on the other hand is a collection of tools designed for platforms like iOS and Android that includes compilers, runtimes, and components to build real-time chat software.

5 Best Instant Messaging APIs & SDKs in 2025

The top 5 best Messaging SDKs are MirrorFly, Twilio, Sendbird, PubNub, and StreamChat. And we will find how unique they are from the rest below:

1. MirrorFly

MirrorFly's chat APIs are highly preferred by developers around for its complete customization and branding capabilities along with 1000+ easy-to-integrate video, voice, and chat features. And the best highlight of this CPaaS provider is that they offer both on-premise and cloud solutions to build feature-rich messaging solutions.

Along with these, they offer pre-built UI kits, multi-tenant servers, and give development support if you need one.

Features

1. Instant messaging and group chats

2. Video conferencing and voice calls

3. Live streaming

4. Push notification

5. Online presence indicators

6. White labeling

7. SIP and VoIP call

Pricing

1. Free Trial: They do not offer free trials but you can get a free demo.

2. Starter Plan: They offer SaaS and SaaP plans. You may reach out to their marketing team for more information.

2. Twilio

Twilio is a cloud communication platform that has been offering messaging SDKs and APIs for over decades. It offers capabilities like chats, voice, video, SMS, and MMS thus making them a solid option for businesses of all sizes.

Along with this, they also integrate well with other CRM systems and customer support solutions.

Features

1. Video calling

2. Screen sharing

3. Rich media support

4. Advanced analytics and reporting

Pricing

1. Free Trial: They give free credit of $15.

2. Starter Plan: Twilio bills at $0.0075 per message.

3. Sendbird

Sendbird is a free chat API provider offering in-app chat, voice, and video capabilities, great flexibility, and customization options. Also, they are a popular choice for enterprises wishing to create social networking and customer support apps because Sendbird's chat SDKs offer security and reliability.

Plus, the best part of this provider is that they support up to 1000K concurrent connections daily.

Features

1. Global language translation

2. User muting and smart throttling

3. Image filtration

4. Moderation tools and profanity filters

Pricing

1. Free Trial: No limit, and you can test most of the features with limited capacity.

2. Starter Plan: $49/month for 1000 MAUs.

4. PubNub

PubNub is one of the leading and most powerful real-time communication platforms that balances uptime SLA so well that it helps resolve concurrency control when multiple users access the app. The platform made this possible with the help of a robust chat system design.

Along with this, PubNub's APIs and SDKs are known for keeping up engagement and user retention with their top-notch features. And their moderation attribute, too, is heavily applauded for preserving the app's integrity.

Features

1. One-to-one and group messaging

2. Multichannel communication

3. Chatbots

4. Real-time notifications

Pricing

1. Free Plan - Includes a free trial that allows you to send 1 million messages per month.

2. Starter Plan - $49/month

5. Stream Chat

Stream Chat, formerly known as GetStream, is the best real-time chat SDK provider for adding instant messaging and news feed attributes to web and mobile apps. Their APs are highly developer-friendly, offering reliability, maintenance, and overall accessibility.

Along with this, Stream offers free chat APIs and SDKs for teams with fewer members and for businesses that generate less than $10k in revenue, as well as UI kits.

Features

1. Instant chats

2. Virtual events

3. Live streams

4. Activity feeds

Pricing

1. Free Plan - You can send up to 5000 monthly messages and a 14-day free trial for premium features.

2. Starter Plan - $99/month

Wrapping Up!

To put it in a nutshell, choosing the right instant messaging SDK comes down to your needs, whether you want a quick integration process, high scalability and customizability, or low latency. Because each provider brings in something unique to the table.

So whether you want to add real-time chat services for your contact center solution or a logistic app, or a healthcare app, there's a solution for every need. You just have to choose the right API provider that will help you deliver an engaging messaging experience to your users.