“Slack is probably the strongest starting point if your main goal is building custom applications on top of an existing chat platform.”
“Web API for messages, conversations, users, files and more.”
“Events API for real-time event delivery.”
“Bolt SDKs for JavaScript, Python and Java.”
“Interactive components, buttons, modals and shortcuts.”
“Best combination of developer productivity, documentation, app extensibility and integration maturity.”
“Microsoft Teams — best for enterprise integration”
“Excellent for organizations already using Microsoft 365, Entra ID, SharePoint and Azure.”
“The ability to embed complete web applications directly inside Teams is particularly valuable.”
“Teams SDK for TypeScript, Python and .NET.”
“Microsoft Graph permissions, throttling and licensing can make some integrations more complicated than they initially appear.”
“Mattermost — best self-hosted developer platform”
“One of the strongest options for custom internal applications when self-hosting and infrastructure control matter.”
“Its plugin architecture is especially interesting.”
“The trade-off is that advanced plugins require Go development.”
“Rocket.Chat — best for deeper platform customization”
“A strong choice when you want to customize both the integration layer and the chat experience itself.”
“Its architecture separates REST operations from real-time event subscriptions, which is useful when developing applications that need both to monitor conversations and perform actions.”
“Discord — best interactive bot ecosystem”
“Its interaction model is particularly good for building command-driven applications.”
“Extensive community-maintained SDK ecosystem.”
“However, Discord is less compelling for enterprise internal applications because its business identity, administration and enterprise integration ecosystem are less developed than Slack or Teams.”
“Matrix — best open protocol and integration flexibility”
“Excellent if you want to build a long-term, platform-independent integration ecosystem.”
“SDKs for JavaScript, Python, Rust, Go and other languages.”
“However, it requires more architectural work than Slack.”
“Encryption also introduces additional considerations for bots and automated message processing.”