API Terms of Service

These API Terms of Service ("API Terms") govern your access to and use of the NannyKeeper Application Programming Interface, including all endpoints under /api/v1/, the NannyKeeper MCP Server, any SDKs, and related developer tools (collectively, the "API").

These API Terms supplement the general Terms of Service and Privacy Policy. In the event of a conflict between these API Terms and the general Terms of Service, these API Terms control with respect to your use of the API. Capitalized terms not defined here have the meanings given in the general Terms of Service.

BY REGISTERING FOR AN API KEY OR MAKING ANY API REQUEST, YOU AGREE TO BE BOUND BY THESE API TERMS. IF YOU DO NOT AGREE, DO NOT USE THE API.

1. API access and authentication

All API requests require a valid API key. API keys are issued to registered NannyKeeper users and are non-transferable. Each API key is bound to the account that created it. You may create up to five (5) API keys per account.

You are solely responsible for maintaining the confidentiality of your API keys. Any activity that occurs using your API key is your responsibility, whether or not you authorized that activity. You must:

• Store keys in environment variables or secure key management systems
• Never embed keys in client-side code, public repositories, or browser-accessible files
• Never share keys with unauthorized third parties
• Immediately revoke and rotate any key you suspect has been compromised

NannyKeeper may revoke or disable any API key at any time, with or without notice, if we reasonably believe the key is being used in violation of these API Terms or poses a security risk.

2. Tiers, rate limits, and quotas

2.1 Free tier

The free tier provides up to 50 API requests per day for tax calculations and threshold checks. Personal and commercial use are permitted. No service level agreement ("SLA") is provided. NannyKeeper may modify free-tier limits at any time with reasonable notice posted to the developer documentation.

2.2 Paid tiers (Starter, Plus)

Paid API access is governed by the same subscription terms as the NannyKeeper web application. The API is an access method for your existing subscription, not a separate product. Your subscription tier determines which endpoints are available, your daily rate limit, and your feature set. If your subscription lapses, is canceled, or enters a past-due state, your API access reverts to the free tier.

2.3 Professional tier

The Professional tier permits managing multiple employer accounts and building products and services on top of the NannyKeeper API, subject to the resale and attribution requirements in Section 4.

2.4 Rate limit enforcement

Rate limits are enforced per account (not per key). Exceeding your rate limit will result in HTTP 429 responses until the limit resets. You must not attempt to circumvent rate limits by creating multiple accounts, rotating keys to reset counters, or any other means.

3. Acceptable use

You agree to use the API only for lawful purposes and in compliance with all applicable laws. You must not:

• Systematically download, scrape, or harvest tax data, state configurations, or any other data to build a competing product or standalone database
• Circumvent rate limits, authentication, or other technical restrictions by any means
• Share, sell, lease, or sublicense API keys to unauthorized third parties
• Create multiple accounts to circumvent per-account limits or restrictions
• Use the API to transmit malware, conduct attacks, or perform any activity that disrupts, damages, or impairs the API or NannyKeeper's infrastructure
• Use the API in a manner that violates any applicable law, regulation, or third-party right, including but not limited to tax fraud, identity theft, or money laundering
• Reverse-engineer, decompile, or attempt to extract the source code or algorithms underlying the API
• Misrepresent your identity, the origin of API requests, or your relationship with NannyKeeper
• Access or attempt to access data belonging to other NannyKeeper users or employers

4. Resale, attribution, and redistribution

4.1 Professional tier — permitted resale with attribution

If you hold a Professional tier subscription, you may build products and services on top of the NannyKeeper API and charge your own customers for access, provided that:

1. You display "Powered by NannyKeeper" with a hyperlink to nannykeeper.com in any user-facing interface that displays NannyKeeper-derived data (tax calculations, payroll results, generated documents, threshold statuses).
2. You do not represent NannyKeeper's calculations, data, or documents as your own proprietary work without the attribution required above.
3. You are solely responsible for your application's user experience, customer support, compliance with applicable laws, and any disputes with your end users.
4. You do not use the NannyKeeper name, logo, or trademarks in a manner that implies endorsement, sponsorship, or affiliation beyond the required "Powered by" attribution.

4.2 Free and Starter/Plus tiers

Resale, redistribution, or commercialization of API output is not permitted on the Free, Starter, or Plus tiers. You may use the API for your own household payroll needs or internal tools only.

4.3 White-label and custom arrangements

For white-label access (no attribution requirement), custom SLAs, volume pricing, or more than 50 employer accounts, contact hello@nannykeeper.com. White-label access requires a separate written agreement.

5. Data, privacy, and security

5.1 Data you send to the API

You are solely responsible for the accuracy, legality, and appropriateness of all data you submit through the API. You represent and warrant that you have all necessary rights, consents, and authorizations to submit such data, including any employee personally identifiable information (PII) such as Social Security numbers, addresses, and bank account details.

5.2 Sensitive data handling

Social Security numbers and bank account details are accepted only through NannyKeeper's hosted portal flows, not through the REST API. This is an intentional security boundary. Employer-side data (W-4 elections, addresses) may be submitted via the API. All sensitive data is encrypted at rest using AES-256-GCM.

5.3 Data retention

API request metadata (endpoint, method, status code, latency, IP address) is logged for analytics, security monitoring, and abuse detection. Request bodies are not stored. Logs are retained for 30 days and then aggregated or deleted.

5.4 Your obligations

If you build an application that collects or processes personal information of third parties using NannyKeeper data, you must maintain a privacy policy that accurately describes your data practices and complies with all applicable privacy laws (including CCPA, where applicable).

6. Caching and data storage

You may cache API responses for up to 24 hours to reduce redundant requests and improve your application's performance. Cached data must not be:

• Redistributed as a standalone dataset or data product
• Used to build a competing database of tax rates, thresholds, or state configurations
• Stored beyond the 24-hour cache window without a fresh API request to validate

Tax rates and thresholds change periodically. The tax_data_version field in response metadata indicates the current version of the underlying tax data. You should invalidate cached results when this version changes.

7. Accuracy, liability, and disclaimers

You are solely responsible for verifying all calculations, filing requirements, and tax obligations with the IRS and relevant state agencies. You acknowledge that:

• Tax laws are complex and change frequently. While we strive to keep our data current, NannyKeeper does not guarantee that calculations reflect the most recent legislative changes at any given moment.
• Free-tier calculations assume zero year-to-date wages. Actual tax obligations may differ based on cumulative wages, Social Security wage base limits, and other year-to-date factors.
• API responses are estimates. They should not be used as the sole basis for tax filings without independent verification.
• If you build a product that presents NannyKeeper calculations to your end users, you must clearly disclose that calculations are estimates and do not constitute professional tax advice.

7.1 Limitation of liability

TO THE MAXIMUM EXTENT PERMITTED BY LAW, NANNYKEEPER SHALL NOT BE LIABLE FOR ANY INDIRECT, INCIDENTAL, SPECIAL, CONSEQUENTIAL, OR PUNITIVE DAMAGES, INCLUDING BUT NOT LIMITED TO LOSS OF PROFITS, DATA, OR BUSINESS OPPORTUNITIES, ARISING OUT OF OR RELATED TO YOUR USE OF THE API, EVEN IF NANNYKEEPER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. NANNYKEEPER'S TOTAL AGGREGATE LIABILITY FOR ALL CLAIMS RELATED TO THE API SHALL NOT EXCEED THE GREATER OF (A) THE AMOUNT YOU PAID TO NANNYKEEPER IN THE TWELVE (12) MONTHS PRECEDING THE CLAIM, OR (B) ONE HUNDRED DOLLARS ($100).

7.2 Indemnification

You agree to indemnify, defend, and hold harmless NannyKeeper and its officers, directors, employees, and agents from any claims, damages, losses, liabilities, costs, and expenses (including reasonable attorneys' fees) arising out of or related to: (a) your use of the API; (b) your violation of these API Terms; (c) your violation of any applicable law; or (d) any third-party claims related to your application or product built on the API.

8. Availability

NannyKeeper does not guarantee any specific uptime or availability for the API. We will use commercially reasonable efforts to maintain the API, but the API is provided "as is" and "as available." We may, without prior notice:

• Perform maintenance that temporarily makes the API unavailable
• Throttle or restrict access to protect infrastructure stability
• Modify, deprecate, or discontinue endpoints (see Section 9)

For custom SLAs with uptime guarantees, contact hello@nannykeeper.com.

9. Versioning, deprecation, and breaking changes

The API uses URL-based versioning (/api/v1/). We may make the following changes without a version bump:

• Adding new endpoints, response fields, or optional request parameters
• Adding new error codes
• Updating tax data (rates, thresholds, state configurations)

Breaking changes (removing fields, changing field types, removing endpoints) will result in a new API version. When a new version launches, the previous version will be supported for at least twelve (12) months before sunset. Deprecated endpoints will return an X-API-Deprecation header. Material changes will be announced via the changelog and email to the address associated with your API key.

10. Suspension and termination

NannyKeeper may suspend or terminate your API access immediately, without prior notice, if we reasonably believe that:

• You are in violation of these API Terms or the general Terms of Service
• Your use poses a security risk to NannyKeeper or its users
• Your use may subject NannyKeeper to legal liability
• Your account is delinquent (for paid tiers)

Upon termination, all API keys associated with your account will be revoked. Sections 4 (attribution obligations for previously distributed content), 5.3 (data retention), 7 (liability and indemnification), and 11 (governing law) survive termination.

11. Changes to these terms

We may update these API Terms from time to time. Material changes will be communicated via email to the address associated with your API key at least thirty (30) days before the changes take effect. Non-material changes (clarifications, formatting, corrections) may be made without notice.

Continued use of the API after the effective date of any changes constitutes your acceptance of the updated terms. If you do not agree to the updated terms, you must stop using the API and revoke your API keys.

12. Governing law and dispute resolution

These API Terms are governed by and construed in accordance with the laws of the State of Washington, without regard to conflict of law principles. Any disputes arising out of or related to these API Terms shall be resolved in accordance with the arbitration and dispute resolution provisions in the general Terms of Service.

13. Contact

Questions about these API Terms? Email hello@nannykeeper.com.