For many nonprofits, communication is the heartbeat of the mission. Whether you’re coordinating events, running programs, managing volunteers, or keeping donors informed — your team needs a reliable way to stay connected.

While Slack is a popular choice, it’s not always the best fit for nonprofit organizations. Slack’s free plan comes with message limits and lacks key admin controls — and many nonprofits can’t justify paying for premium tiers.

If you’re looking for a better option, here are the top Slack alternatives for nonprofits in 2025 — starting with the one designed to help mission-driven teams communicate clearly and stay organized.

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1. Zenzap  – The Best Free Slack Alternative for Nonprofits

Best for: Nonprofits that need professional features on a nonprofit-friendly budget

Zenzap is an ideal choice for nonprofits seeking a Slack alternative that’s simple, powerful, and affordable (free forever!). It’s built for real teams, not just tech companies — and it includes key features that nonprofit leaders and managers actually use.

✅ Features nonprofits love:

• Unlimited team members — perfect for organizations with many volunteers
  
• Group channels + private DMs
  
• Built-in task management (assign tasks inside chats — great for volunteer coordination!)
  
• Admin controls: set work hours, remove messages, offboard members quickly
  
• Available on desktop and mobile
  
• No message history caps
  
  

💬 Why it’s a great fit for nonprofits:

Zenzap’s clean interface makes onboarding staff and volunteers easy — even if they aren’t tech-savvy. The built-in task tools help project managers and coordinators keep everything running smoothly, without needing extra apps. And the free forever plan means nonprofits can save critical funds for their mission.

“Zenzap gave our nonprofit a better way to manage projects and volunteers — without having to pay for enterprise tools.” — Nonprofit Director

👉 Try Zenzap — Free Forever

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2. Mattermost (Open Source)

Best for: Nonprofits with in-house tech support that want open-source control

Mattermost is an open-source Slack alternative that offers private cloud or self-hosted options — giving nonprofits full control over their data and compliance.

✅ Pros:

• Open-source and customizable
  
• Strong privacy and security options
  
• Self-hosted for full data ownership
  
  

⚠️ Cons:

• Requires technical expertise to set up and manage
  
• More complex for non-technical users

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3. Flock

Best for: Nonprofits looking for a lightweight, affordable chat tool

Flock offers chat, channels, video calling, and integrations in a lightweight, affordable package. It’s a good option for smaller nonprofits with simple communication needs.

✅ Pros:

• Affordable premium plans
  
• Easy to set up and use
  
• Integrations with popular tools like Google Drive
  
  

⚠️ Cons:

• Free plan has limits
  
• Smaller user community and fewer integrations than bigger platforms
  
  

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4. Google Chat (with Google Workspace for Nonprofits)

Best for: Nonprofits already using Google Workspace (Gmail, Docs, Drive)

If your nonprofit is already using Google Workspace (which many nonprofits get for free or at a discount), Google Chat is a natural alternative to Slack.

✅ Pros:

• Integrated with Gmail, Docs, Calendar
  
• Free/discounted as part of Google for Nonprofits
  
• Simple and familiar interface
  
  

⚠️ Cons:

• Lacks advanced admin features
  
• Basic compared to more purpose-built team chat apps
  
  

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5. ClickUp Chat

Best for: Nonprofits that need project management + chat in one tool

ClickUp is best known as a project management platform, but it also includes built-in chat. If your nonprofit needs a Slack alternative + project management in one place, ClickUp is worth considering.

✅ Pros:

• Combines chat and project/task management
  
• Free plan available
  
• Good for organizing teams and tracking work
  
  

⚠️ Cons:

• Chat features are secondary to project management
  
• Interface can feel overwhelming at first
  
  

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Final Thoughts: The Best Slack Alternative for Nonprofits

Nonprofits deserve tools that are easy to use, affordable, and effective — without spending precious budget on enterprise software.

If you’re looking for a Slack alternative that truly fits nonprofit teams, Zenzap offers the best balance of simplicity, features, and value:

✅ Free forever

✅ Unlimited users

✅ Built-in task management

✅ Easy for staff and volunteers to use

👉 Start using Zenzap for your nonprofit — Free Forever