Windmill drafts each review. The manager gives the rating.

Ten free seats, AI drafts and no uptime figure in the terms

What Windmill’s customers report

Windmill reports more than 100 customers, including Kalshi, Rho and Merge. It launched its review product in November 2025.

Rho is a banking platform for startups. Rho reports that a review takes 6.5 minutes on average and that the full cycle took 8 days. It reports 83% fewer total hours and 93% of employees preferring Windmill. Case Status reports completing its cycle in 84% less time. It also reports that 93% of employees preferred Windmill to the old system.

NALA has a team of 80 or more people in 18 countries. It reports 537 hours saved. Allwhere reports about 20 hours of manual review work removed per manager. A RetailNext director of engineering reports that review preparation fell from three hours per person to about half an hour. Nirvana reports a 100% completion rate for self and upward reviews. Stepful reports that satisfaction with its review cycle rose 18%.

A manager can finish a full review in as little as six minutes when there is enough data behind it. Ask Windmill for customer references, and how many cycles each has run.

Where Windmill stops

Windmill, Inc. runs its website, platform and servers in the US. Its infrastructure is hosted in Amazon Web Services data centres in the US. Users outside the US consent to a transfer of their data by using the platform, under its privacy policy. Under its terms, the platform is based in the US and is not claimed to suit use outside it. Under the same terms, a separate data processing agreement governs processing of personal information if the parties have signed one. Ask for one.

Windmill reserves the right to change, suspend, discontinue or end access to any part of the platform at any time. It may do so without prior notice or liability. Windmill commits to commercially reasonable efforts to minimise downtime and sets no uptime percentage. Under its terms, direct damages are limited to the fees paid and payable in the three months before the claim. The customer must bring any claim within one year of the event behind it. JAMS, an arbitration firm, runs binding arbitration of disputes under the Federal Arbitration Act. New York law governs the terms. Windmill commits to notify the customer within 72 hours of discovering a security breach that affects personal information.

Its help centre puts the support response at under 24 hours, with typical replies in under 10 minutes. Its terms put it at one business day, 9 am to 5 pm Eastern, Monday to Friday. The shared Slack channel is best effort under the terms. Ask which promise goes into your contract.

On AI and data, Windmill’s help centre and its terms differ. Its help centre puts zero data retention across all its AI providers, which are OpenAI, Anthropic and Google. Under its terms, the customer’s input may be used by those providers under their own terms. Under the same terms, Windmill has no control over that use. Ask for a written answer.

Windmill may use anonymised customer data to improve its own models. Under its terms, Windmill may train or optimise its platform models on anonymised customer data or aggregate data. The uses include classification, scoring, routing and anomaly detection. Under the same terms, Windmill may also sell and otherwise exploit anonymous, aggregated customer data. Windmill gives customers an opt-out by email from the use of anonymised data in its own models. It confirms the opt-out in writing. Under its terms, Windmill will not use customer data to train foundational or general-purpose AI models.

Under its terms, Windmill makes no representation about the accuracy of outputs. The customer is solely responsible for evaluating them. The customer is also solely responsible for making sure that input and output comply with applicable laws. The customer promises not to enter Sensitive Information in the platform.

Managers can see stats for their team, including indirect reports. The stats include the number of Slack messages sent. With the Claude AI tool connected, a manager can also see its usage by direct reports and their reporting chain. Authorised managers or HR admins can read shared one-to-one notes and history when the company turns on one-to-one auditability. Ask who can see each item.

Connecting Slack does not give Windmill the messages in a channel. The app has to be added to a channel first. Windmill recommends an admin setting called Autojoin public channels. It gives Windmill automatic access to public channels. Only human members of a private channel can read its raw messages in Windmill.

Conditional questions are not available, so one answer cannot show or hide another question. After review work starts, an admin cannot add or remove questions or change a question type. Later org chart changes do not update the reviewees and managers saved when a cycle is created. Extra cycle data goes in through Windmill’s API, a software connection. There is no dashboard upload form or import of CSV files, which are plain spreadsheet files. Peer and upward feedback carries the reviewer’s name. The person reviewed cannot read it.

Its help pages put access to its HR systems, except Rippling, as read-only. Under its terms, the customer shall give Windmill read and write access to third-party services it selects, or obtain permission. Ask which applies.

The first 10 seats are free and each extra seat costs $10 a month

Windmill charges for each account you set up. An invited employee counts as a seat even before they log in. The standard plan includes 10 free seats, and some plans include a different number. Each extra seat costs $10 USD a month. At 90 seats, 80 are paid, which comes to $800 a month. Free seats stay free however many seats you add.

Customers can connect as many of Windmill’s 35 or more integrations as their team uses. The price also includes sign-in through a company login system and automatic user set-up. Windmill bills the default payment method once a month through Stripe. Archiving a member removes the seat from future invoices and gives no refund for the current month.

Windmill also offers training sessions for teams, managers and admins. Ask whether training costs extra.

The agreement renews automatically for terms equal to the plan unless you give 30 days’ notice before the term ends. Under its terms, fees paid are non-refundable, and Windmill may add new or additional fees on notice. Its billing help page puts cancellation in the Stripe billing portal. The account stays active to the end of the billing period. Its terms put cancellation at an email to support, effective at the end of the term. Windmill may charge a fee to restore access it suspended for non-payment.

After the contract ends, you have up to 30 days to retrieve your data. Cycle admins export a cycle. They get one ZIP file of spreadsheet (CSV) files per stage and a PDF packet per person reviewed. Windmill emails you when it is ready. The download link works for 48 hours. Archived cycles cannot be exported. Calibration comments, review-sharing comments and sharing history are not in the export. Windmill puts only completed reviews in the PDF packets, not drafts or unsubmitted reviews. You can ask for full deletion of your data after the engagement ends.

Ten questions to ask before you sign

1. In which country will our staff data be stored and processed? Will you sign a data processing agreement? Good answer: A named country, and a signed agreement that covers every country where our staff work.
2. Will you put an uptime percentage and one support response time in our contract? Good answer: A percentage, and a single response time that matches your help pages and your terms.
3. Will you confirm in the contract that our anonymised and combined data stays out of your own models? Good answer: Yes, in writing, before we sign.
4. Does each of your AI providers keep any of our staff’s text? Good answer: A written answer for each provider that matches the zero data retention promise.
5. Who can see Slack message counts, Claude usage and one-to-one notes? Can we switch each one off? Good answer: A list of roles and settings for each item.
6. Your help pages call the HR connections read-only. Your terms say we shall grant read and write access. Which applies? Good answer: A written answer for each HR system we use.
7. How do we cancel, and on which date does our term end? Good answer: One method and one date, both stated in the order form.
8. What counts as Sensitive Information that we must not enter? Good answer: A written list that we can give to every manager.
9. Which accessibility standard does Windmill meet? Can we see its accessibility report, called a VPAT? Good answer: A named standard and a current report.
10. How do we export calibration comments and sharing history when we leave? Good answer: A file format and a deadline in the contract.

Alternatives to Windmill

Topicflow, Effy AI, Teamflect, Lattice, 15Five and Leapsome run review cycles. Risely’s Merlin coaches managers who write reviews.

Topicflow has a free plan for 10 users and a Pro plan at $10 per user a month. Its Ultimate plan costs $15 per user a month and is the plan sold for running review cycles. Effy AI is AI-first performance software that runs in the browser, inside Slack or inside Microsoft Teams. Its free plan covers up to 5 users. Its Performance suite, which covers reviews and goals, costs $9 per seat a month billed annually. When you upgrade from the free plan, all users are billed.

Teamflect is built natively for Microsoft Teams and Outlook. Its Starter plan costs nothing for up to 10 users. Its Professional plan costs $11 per user a month billed annually. Windmill connects to Slack and Google, and members can sign in through Microsoft.

Lattice charges $10 per seat a month for Performance, and its minimum annual agreement is $4,000. Review drafts built from past Lattice data come with every Performance subscription at no extra cost. 15Five charges $11 per user a month for Perform, billed annually. Its AI-assisted reviews left beta on 17 September 2026. Leapsome charges EUR 7 per employee a month for Performance Reviews. Leapsome sells Performance Reviews only together with its platform.

Risely’s Merlin is an AI coach and runs no review cycle. Managers use Merlin to draft review feedback based on their company’s standards and guidelines. Managers can also upload feedback they have already written. Merlin then coaches them on aligning it with the company’s feedback guidelines. Merlin coaches managers on best practice for giving constructive feedback. In Risely, an admin sets up the company’s feedback guidelines. Merlin coaches the wording of the feedback. The manager writes it and gives the rating. Risely’s enterprise plan includes review-feedback coaching.

Windmill, Teamflect, Topicflow and Effy AI each offer a free plan for a small team. That is 10 seats at Windmill, 10 users at Teamflect and Topicflow, and 5 users at Effy AI. A team inside those limits can run reviews at no cost on Windmill, Teamflect or Effy AI. Topicflow sells review cycles on its $15 plan. You can also buy nothing.