AIP Numbering

The AIP system provides a mechanism to index and have a single source of truth for API Improvement Proposals, as well as iterate on them collaboratively and transparently.

This document describes the AIP numbering system.

Assigning AIP Numbers

The AIP editors (see AIP-1) are responsible for assigning a number to each AIP when it is accepted as a draft for review. Importantly, all AIPs have numbers, not just approved ones. The AIP Index clearly delineates which AIPs are approved and binding and which are under discussion.

The editors may decide to reserve a specific block of numbers for groups of AIPs that are related in some way (for example, that are only scoped to a specific subset of APIs).

Beyond this, AIP numbers are assigned arbitrarily. In general, the editors will take the next AIP number off of the stack to assign to a draft AIP, but occasionally may use a special/joke number if useful for mnemonic or other reasons.

AIP Blocks

Currently recognized blocks of AIP numbers are:

Generally Applicable

  • 1-99: Reserved for meta-AIPs (generally process-related).
  • 100-999: General API design guidance

Google Product Areas

  • 2700-2799: Apps (Google Workspace)
  • 2500-2599: Cloud
  • 3000-3099: Actions on Google
  • 3200-3299: Firebase
  • 4100-4199: Auth libraries
  • 4200-4299: Client libraries
  • 4600-4699: Geo

To request a block for a specific team that is publishing API guidance or documentation germane to that specific team, reach out to api-editors@.


  • 2019-10-03: The 3000-3099 block was assigned to Actions on Google.
  • 2019-01-26: The general API design guidance block was expanded to include 100-199.
  • 2018-10-24: The 4600-4699 block was assigned to Google Geo.
  • 2018-10-02: The 2500-2599 block was assigned to Google Cloud Platform.
  • 2018-10-02: The 2700-2799 block was assigned to Google Workspace.