Windmill vs 15Five: Which Fits Your Team?
Compare Windmill and 15Five for performance management. Side-by-side breakdown of features, pricing, AI capabilities, and who each platform is best for.
Windmill and 15Five both help companies run performance reviews and develop managers. But they approach it differently. Windmill automates the process through AI. 15Five structures it through weekly check-ins and manager coaching tools.
The right pick depends on what your team needs most.
What Is Windmill?
Windmill is an AI-native performance management platform. Its AI assistant, Windy, lives in Slack and handles the entire review cycle: gathering data from work tools, conducting self-reviews through Slack conversations, collecting peer feedback, and generating manager drafts.
Windy connects to GitHub, Linear, Jira, Asana, Salesforce, Figma, Notion, and 20+ other tools to track what people actually accomplish. Reviews are 90% written before managers even open them.
Companies like Merge, TickPick, and cal.com use Windmill to run their review cycles.
Core features:
- AI-conducted reviews via Slack conversation
- Auto-sync from GitHub, Jira, Linear, Salesforce, Notion, 20+ tools
- AI-generated 1:1 agendas from Slack, calendar, and tool activity
- Continuous feedback prompted by real collaboration patterns
- Calibration dashboard with discrepancy flagging
- Performance review automation with full review drafts
- Goal tracking with automated progress monitoring
What Is 15Five?
15Five is a performance management platform built around weekly check-ins and manager enablement. Founded in 2011, it has grown to serve 3,500+ companies including Credit Karma, HubSpot, and Pendo.
The platform’s signature feature is the weekly check-in: employees spend 15 minutes answering questions about how they’re feeling, updating goals, and flagging priorities. Managers review in about 5 minutes and push key topics to 1:1 agendas.
In January 2025, 15Five acquired Kona, an AI coaching tool for managers, signaling a strategic shift toward manager enablement as its core differentiator.
Core features:
- Weekly employee check-ins with feeling assessments
- Performance reviews with 360-degree feedback
- OKR and goal management with alignment visualization
- Engagement surveys with heat maps and benchmarking
- Kona AI Meeting Assistant and AI Coach (paid add-ons)
- Talent Matrix (9-box grid) for calibrating talent
- High Fives peer recognition
- Manager training and coaching programs (paid add-ons)
Key Differences
How Reviews Get Done
Windmill’s AI agent Windy conducts the entire review process autonomously. It chats with employees in Slack to build self-reviews, interviews peer reviewers with targeted follow-ups, and compiles everything into a draft for managers. Managers select key points, edit the draft, and submit. Total time: about 6 minutes per review.
15Five runs reviews through customizable cycles with self-reviews, peer reviews, and manager reviews. AI-assisted review writing pulls from check-in history, engagement data, and coaching records to help generate drafts. But the process still depends on employees filling out forms, managers writing assessments, and HR configuring cycles. Total time is significantly longer than Windmill, though shorter than fully manual approaches.
Where the Work Happens
Windmill is Slack-first. Self-reviews, peer feedback, and 1:1 prep all happen in the tool your team already uses every day. There’s also a full web dashboard for HR admins, managers reviewing drafts, and running calibrations, but the day-to-day employee experience lives in Slack.
15Five has its own web platform. While it integrates with Slack and Teams for notifications and peer recognition (High Fives), core workflows like check-ins, reviews, and goal updates happen in the 15Five dashboard.
Data Sources
Windmill syncs with the tools where work actually happens: GitHub for code, Jira and Linear for tickets, Salesforce for deals, Figma for designs, Notion for docs, Slack for collaboration patterns. When review time comes, the data is already there.
15Five’s data comes primarily from within 15Five itself: weekly check-ins, survey responses, goal updates, and manager notes. It integrates with HRIS systems like BambooHR, Workday, and Gusto for employee data, but doesn’t pull from project management or engineering tools. Managers gather work context separately.
AI Approach
Windmill is AI-native. The AI isn’t a feature; it’s how the product works. Windy runs the review process, generates 1:1 agendas, surfaces accomplishments, and identifies collaboration patterns through organizational network analysis.
15Five has been layering AI onto its existing platform. The Kona acquisition brought AI coaching (nudges in Slack for managers) and meeting transcription. AMAYA lets HR leaders query data conversationally. AI-assisted review writing helps generate drafts. These are useful additions, but they’re add-ons to a fundamentally manual workflow, and they cost extra.
Manager Enablement
This is where 15Five stands out. Their platform is designed to make managers better at their jobs through structured check-ins, coaching programs, and training content. The Kona AI Coach ($19/manager/month) delivers personalized nudges. On-demand learning libraries and live coaching sessions with professional coaches are available as add-ons.
Windmill takes a different approach: rather than training managers to do admin work better, it removes the admin work entirely. Managers spend their time reviewing AI-generated drafts and having substantive conversations instead of collecting data and writing from scratch.
Engagement Surveys
15Five includes robust engagement surveys in its Engage tier ($4/user/month): heat maps, data breakdowns, industry benchmarking, and action planning tools. Surveys are a core part of the product.
Windmill offers pulse surveys through conversational Slack interactions rather than traditional form-based surveys. Windy chats with employees to gather sentiment rather than sending static questionnaires.
Pricing
Windmill: First 10 seats free, then $10/seat/month. Everything included: reviews, feedback, 1:1s, goals, calibrations, surveys.
For 100 people: $900/month ($10,800/year).
15Five: Three tiers, all billed annually.
| Tier | Price | What You Get |
|---|---|---|
| Engage | $4/user/month | Engagement surveys only |
| Perform | $11/user/month | Reviews, OKRs, 360 feedback, Talent Matrix |
| Total Platform | $16/user/month | Everything above + manager training |
Add-ons stack up: Kona AI Meeting Assistant ($2/employee/month), Kona AI Coach ($19/manager/month), Compensation ($9-11/user/month), live coaching ($399/session).
For 100 people on Perform: $1,100/month ($13,200/year). Add Kona AI and coaching and you’re north of $20,000/year.
When to Choose Windmill
Best for teams that want:
- Performance management that runs itself through AI
- Reviews completed in minutes, not hours
- Data pulled automatically from engineering, sales, and collaboration tools
- Everything in Slack with no separate platform to manage
- Simple pricing with no add-on surprises
- Setup in under an hour
Works best for tech companies, startups, and knowledge-work teams where employees do most of their work in digital tools.
When to Choose 15Five
Best for organizations that want:
- Structured weekly check-ins as a core management practice
- Deep engagement survey capabilities with benchmarking
- Manager coaching and training programs
- A mature platform with 3,500+ customers and a long track record
- Compensation management in the same tool
- Gradual AI adoption as optional add-ons
Works well for mid-market companies (50-200 employees) that prioritize manager development alongside performance management.
Bottom Line
15Five built a solid platform around weekly check-ins and manager enablement over 15 years. If your main goal is structured manager-employee communication and coaching programs, 15Five delivers.
Windmill built with AI from day one. If your main pain is the review process itself, the hours of data collection, form-filling, and draft-writing, Windmill eliminates it. Reviews take 6 minutes instead of 6 hours, and managers spend their time on people development instead of paperwork.
Want to stop running reviews and start having them run themselves? Try Windmill.
Frequently Asked Questions
What is the main difference between Windmill and 15Five?
Windmill automates the entire performance review process through AI that gathers data, conducts reviews via Slack conversation, and generates drafts. 15Five centers on weekly check-ins, manager coaching, and engagement surveys, requiring managers to drive most of the process manually. Windmill replaces admin work; 15Five structures it.
How does 15Five pricing compare to Windmill?
Windmill starts free for 10 seats, then costs $10/seat/month with everything included. 15Five's Engage tier starts at $4/user/month but only covers surveys. Performance reviews require the Perform tier at $11/user/month, and AI coaching add-ons push costs to $20-30+/user/month. Windmill is simpler and cheaper at scale.
Does 15Five have AI features?
Yes. 15Five acquired Kona in January 2025 and offers an AI Meeting Assistant ($2/employee/month) and AI Coach for managers ($19/manager/month). They also have AI-assisted review writing and a conversational analytics tool called AMAYA. However, AI features are add-ons, not core to the platform like Windmill.
Is Windmill or 15Five better for engineering teams?
Windmill is better for engineering teams because it integrates directly with GitHub, Jira, Linear, and Asana to track actual work output. 15Five tracks goals and weekly check-ins but doesn't pull data from engineering tools, so managers still need to manually gather context about code contributions and project delivery.