Substack Developer API Terms of Use
Last updated: January 8, 2026
These Developer API Terms of Use (“API Terms”) govern your access to and use of the Substack Inc. (“Substack”) application programming interfaces and related documentation (collectively, the “API”). By accessing or using the API, you agree to be bound by these API Terms, the Substack Terms of Service, and the Substack Privacy Policy (collectively, the “Agreement”). If you do not agree, you must not access or use the API.
1. License and Authorized Use
Subject to your compliance with the Agreement, Substack grants you a limited, revocable, non-exclusive, non-transferable, non-sublicensable license to access and use the API solely for the Permitted Uses described in these API Terms.
All rights not expressly granted are reserved by Substack. Substack may revoke this license at any time.
2. Authorized Data
The API may return certain information that is publicly available on creators’ public profiles or publications on the Substack platform (“Authorized Data”), which may include:
Name
LinkedIn URL
Social identity URLs
Total subscriber count
Bestseller status
Leaderboard recognitions (e.g., category rankings)
Profile summary
Profile URL
Publication URL
Authorized Data consists only of information that creators have chosen to make publicly visible and does not include private, restricted, or inferred information.
3. Permitted Uses
You may use Authorized Data solely to:
Display or present public creator or publication information
Enable discovery, analytics, or integrations involving public profiles or publications
Support user-facing features that reference or link to the original public source
You may cache Authorized Data only as reasonably necessary to support your application, and you must refresh or delete cached data to ensure consistency with the current public state.
4. Prohibited Uses
You shall not, directly or indirectly:
a. Use the API or Authorized Data to derive, infer, or attempt to determine any non-public, sensitive, or personal attributes of a creator;
b. Aggregate Authorized Data in a manner that enables surveillance, profiling, or behavioral targeting of creators;
c. Use Authorized Data for unsolicited communications, spam, or harassment;
d. Sell, license, sublicense, or redistribute Authorized Data as a standalone product or dataset;
e. Use the API to replicate, substitute for, or materially compete with core features of the Substack platform;
f. Misrepresent the source, ownership, or completeness of Authorized Data; or
g. Combine Authorized Data with other data sources in a manner that violates applicable law or these API Terms.
5. Rate Limits and Access Controls
Your use of the API is subject to rate limits, quotas, and other technical restrictions as determined by Substack in its sole discretion. You agree not to circumvent or attempt to bypass such restrictions.
Substack may modify, suspend, or terminate API access or limits at any time.
6. Attribution and Presentation
Where reasonably practicable, you must attribute Authorized Data to Substack and provide a link to the applicable public profile or publication.
You must not present Authorized Data in a misleading manner or imply endorsement, partnership, or affiliation by Substack or any creator.
7. Data Accuracy and Creator Control
Authorized Data is provided on an “as is” and “as available” basis. Substack does not guarantee accuracy, completeness, or timeliness.
Creators control the information displayed on their public profiles and publications. If a creator modifies or removes public information, you must promptly update or delete corresponding Authorized Data.
8. Compliance with Laws
You are solely responsible for ensuring that your use of the API and Authorized Data complies with all applicable laws, regulations, and self-regulatory standards, including privacy, data protection, and consumer protection laws.
9. Suspension and Termination
Substack may suspend or terminate your access to the API immediately, with or without notice, if Substack determines that your use of the API or Authorized Data violates the Agreement or poses a risk to creators, users, or the platform.
Upon termination, you must cease all use of the API and delete any retained Authorized Data.
10. Disclaimer of Warranties
THE API AND AUTHORIZED DATA ARE PROVIDED “AS IS” AND “AS AVAILABLE,” WITHOUT WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING WARRANTIES OF ACCURACY, NON-INFRINGEMENT, MERCHANTABILITY, OR FITNESS FOR A PARTICULAR PURPOSE.
11. Limitation of Liability
TO THE MAXIMUM EXTENT PERMITTED BY LAW, SUBSTACK SHALL NOT BE LIABLE FOR ANY INDIRECT, INCIDENTAL, CONSEQUENTIAL, SPECIAL, OR PUNITIVE DAMAGES ARISING OUT OF OR RELATING TO THE API OR AUTHORIZED DATA.
12. Modifications
Substack may modify or discontinue the API or these API Terms at any time. Continued use of the API after the effective date of any modification constitutes acceptance of the updated terms.
13. Governing Law
These API Terms are governed by the laws of California.
14. Technical documentation
A support article with technical documentation for generating an api key and using the api can be found Here.
