# Really Simple Licensing vs AIPREF Vocabulary

The map lists them as complementary: sites and agents commonly implement both.

[3 Permit](/category/permit/) [Really Simple Licensing](/protocols/rsl/) · [3 Permit](/category/permit/) [AIPREF Vocabulary](/protocols/aipref-vocabulary/)

|  | [Really Simple Licensing](/protocols/rsl/) RSL | [AIPREF Vocabulary](/protocols/aipref-vocabulary/) AIPREF |
| --- | --- | --- |
| Lifecycle step | 3 Permit: What may the agent do here? | 3 Permit: What may the agent do here? |
| Answers | What machine-readable license, price, and authorization terms govern how AI systems and crawlers may access or reuse a publisher's content? | What controlled set of values expresses a publisher's AI-use preferences, independent of how they are attached to content? |
| Governed by | RSL Collective, a vendor consortium; issue tracker at github.com/rslstandard/rsl | IETF AI Preferences Working Group (ai-control@ietf.org mailing list) |
| Status (issuer's words) | Recommendation (RSL's own maturity label, not a W3C/IETF Recommendation) — Document RSL-SPEC-1.0, Category 'Industry Specification' | Internet-Draft, work in progress; explicitly states its contents 'DO NOT REFLECT CONSENSUS of the Working Group' |
| Phase | stable | working group |
| Version | RSL 1.0 (2025-12-10) | draft-ietf-aipref-vocab-08 (2026-09-14) |
| Form / transport | document format | document format |
| Found at | /rsl.xml | Not independently discoverable; values are carried by the Content-Usage attachment mechanism (robots.txt directive or HTTP header) |
| Adoption | unmeasured | unmeasured |
| Evidence | 2 verified | 2 verified, 1 reported |
| Primary use case | Control AI crawling and training use | Control AI crawling and training use |
| Last verified | 2026-10-16 (current) | 2026-10-18 (current) |
| Specification | [https://rslstandard.org/rsl](https://rslstandard.org/rsl) | [https://datatracker.ietf.org/doc/html/draft-ietf-aipref-vocab-08](https://datatracker.ietf.org/doc/html/draft-ietf-aipref-vocab-08) |

## When to use which

- Choose Really Simple Licensing when your question is “What machine-readable license, price, and authorization terms govern how AI systems and crawlers may access or reuse a publisher's content?” and you accept its maturity: phase stable, adoption unmeasured.
- Choose AIPREF Vocabulary when your question is “What controlled set of values expresses a publisher's AI-use preferences, independent of how they are attached to content?” and you accept its maturity: phase working group, adoption unmeasured.

Guidance is derived from the two records (question, phase, adoption, prerequisites, pairings), not from opinion. Each record's page carries its numbered references.

## Read the full articles

- [Really Simple Licensing](/protocols/rsl/): What machine-readable license, price, and authorization terms govern how AI systems and crawlers may access or reuse a publisher's content?
- [AIPREF Vocabulary](/protocols/aipref-vocabulary/): What controlled set of values expresses a publisher's AI-use preferences, independent of how they are attached to content?

Ask the MCP server to compare any two: the compare-protocols prompt, or get on both ids. [Connect](/connect/).

[rsl.json](/data/protocols/rsl.json) · [aipref-vocabulary.json](/data/protocols/aipref-vocabulary.json) · [Markdown](/compare/rsl-vs-aipref-vocabulary/index.md)