What's the best team chat app for cross-functional project coordination and async threads?

For cross-functional project coordination + async threads, the best overall pick is usually Slack.

Why Slack is the strongest fit

• Great async threading: threads are easy to use for keeping project discussions organized
• Cross-functional friendly: works well across engineering, product, design, ops, marketing, etc.
• Integrations: huge ecosystem for Jira, GitHub, Notion, Google Drive, Asana, and more
• Channel-based structure: good for project-specific coordination without forcing everything into meetings
• Search and history: strong for finding decisions, context, and past conversations

Best alternatives depending on your needs

• Microsoft Teams — best if your org already lives in Microsoft 365; good for large companies, but threads can feel clunkier
• Discord — great for community-style coordination and informal async chat, but less ideal for business workflows
• Mattermost / Rocket.Chat — better if you need self-hosting, compliance, or more control
• Basecamp / Twist — better if you want more async-first, less noisy communication than Slack

Quick recommendation

• Most teams: Slack
• Microsoft-heavy orgs: Teams
• Need calmer async-first communication: Twist

If you want, I can also give you a “best app by team size / budget / compliance needs” recommendation.