BIP 0001

What is a BEP?

BEP stands for Bitcoin Enhancement Proposal. A BEP is a design document providing information to the Bitcoin community, or describing a new feature for Bitcoin or its processes or environment. The BEP should provide a concise technical specification of the feature and a rationale for the feature.

We intend BEPs to be the primary mechanisms for proposing new features, for collecting community input on an issue, and for documenting the design decisions that have gone into Bitcoin. The BEP author is responsible for building consensus within the community and documenting dissenting opinions.

Because the BEPs are maintained as text files in a versioned repository, their revision history is the historical record of the feature proposal .

BEP Types

There are three kinds of BEP:

• A Standards Track BEP describes a new feature or implementation for Bitcoin.
• An Informational BEP describes a Bitcoin design issue, or provides general guidelines or information to the Bitcoin community, but does not propose a new feature. Informational BEPs do not necessarily represent a Bitcoin community consensus or recommendation, so users and implementors are free to ignore Informational BEPs or follow their advice.
• A Process BEP describes a process surrounding Bitcoin, or proposes a change to (or an event in) a process. Process BEPs are like Standards Track BEPs but apply to areas other than the Bitcoin language itself. They may propose an implementation, but not to Bitcoin's codebase; they often require community consensus; unlike Informational BEPs, they are more than recommendations, and users are typically not free to ignore them. Examples include procedures, guidelines, changes to the decision-making process, and changes to the tools or environment used in Bitcoin development. Any meta-BEP is also considered a Process BEP.

BEP Work Flow

The BEP editors assign BEP numbers and change their status. Please send all BEP-related email to <BEPs@Bitcoin.org> (no cross-posting please). Also see BEP Editor Responsibilities & Workflow below.

The BEP process begins with a new idea for Bitcoin. It is highly recommended that a single BEP contain a single key proposal or new idea. Small enhancements or patches often don't need a BEP and can be injected into the Bitcoin development work flow with a patch submission to the Bitcoin issue tracker. The more focussed the BEP, the more successful it tends to be. The BEP editor reserves the right to reject BEP proposals if they appear too unfocussed or too broad. If in doubt, split your BEP into several well-focussed ones.

Each BEP must have a champion -- someone who writes the BEP using the style and format described below, shepherds the discussions in the appropriate forums, and attempts to build community consensus around the idea. The BEP champion (a.k.a. Author) should first attempt to ascertain whether the idea is BEP-able. Posting to the comp.lang.Bitcoin newsgroup (a.k.a. Bitcoin-list@Bitcoin.org mailing list) or the Bitcoin-ideas mailing list is the best way to go about this.

Vetting an idea publicly before going as far as writing a BEP is meant to save the potential author time. Many ideas have been brought forward for changing Bitcoin that have been rejected for various reasons. Asking the Bitcoin community first if an idea is original helps prevent too much time being spent on something that is guaranteed to be rejected based on prior discussions (searching the internet does not always do the trick). It also helps to make sure the idea is applicable to the entire community and not just the author. Just because an idea sounds good to the author does not mean it will work for most people in most areas where Bitcoin is used.

Once the champion has asked the Bitcoin community as to whether an idea has any chance of acceptance, a draft BEP should be presented to Bitcoin-ideas. This gives the author a chance to flesh out the draft BEP to make properly formatted, of high quality, and to address initial concerns about the proposal.

Following a discussion on Bitcoin-ideas, the proposal should be sent to the Bitcoin-dev list with the draft BEP and the BEP editors <BEPs@Bitcoin.org>. This draft must be written in BEP style as described below, else it will be sent back without further regard until proper formatting rules are followed.

If the BEP editor approves, he will assign the BEP a number, label it as Standards Track, Informational, or Process, give it status "Draft", and create and check-in the initial draft of the BEP. The BEP editor will not unreasonably deny a BEP. Reasons for denying BEP status include duplication of effort, being technically unsound, not providing proper motivation or addressing backwards compatibility, or not in keeping with the Bitcoin philosophy.

As updates are necessary, the BEP author can check in new versions if they have SVN commit permissions, or can email new BEP versions to the BEP editor for committing.

Standards Track BEPs consist of two parts, a design document and a reference implementation. The BEP should be reviewed and accepted before a reference implementation is begun, unless a reference implementation will aid people in studying the BEP. Standards Track BEPs must include an implementation -- in the form of code, a patch, or a URL to same -- before it can be considered Final.

BEP authors are responsible for collecting community feedback on a BEP before submitting it for review. However, wherever possible, long open-ended discussions on public mailing lists should be avoided. Strategies to keep the discussions efficient include: setting up a separate SIG mailing list for the topic, having the BEP author accept private comments in the early design phases, setting up a wiki page, etc. BEP authors should use their discretion here.

For a BEP to be accepted it must meet certain minimum criteria. It must be a clear and complete description of the proposed enhancement. The enhancement must represent a net improvement. The proposed implementation, if applicable, must be solid and must not complicate the protocol unduly.

Once a BEP has been accepted, the reference implementation must be completed. When the reference implementation is complete and accepted by the community, the status will be changed to "Final".

A BEP can also be assigned status "Deferred". The BEP author or editor can assign the BEP this status when no progress is being made on the BEP. Once a BEP is deferred, the BEP editor can re-assign it to draft status.

A BEP can also be "Rejected". Perhaps after all is said and done it was not a good idea. It is still important to have a record of this fact.

BEPs can also be superseded by a different BEP, rendering the original obsolete. This is intended for Informational BEPs, where version 2 of an API can replace version 1.

The possible paths of the status of BEPs are as follows:

File:BEP Process

Some Informational and Process BEPs may also have a status of "Active" if they are never meant to be completed. E.g. BEP 1 (this BEP).

What belongs in a successful BEP?

Each BEP should have the following parts:

• Preamble -- RFC 822 style headers containing meta-data about the BEP, including the BEP number, a short descriptive title (limited to a maximum of 44 characters), the names, and optionally the contact info for each author, etc.

• Abstract -- a short (~200 word) description of the technical issue being addressed.

• Copyright/public domain -- Each BEP must either be explicitly labelled as placed in the public domain (see this BEP as an example) or licensed under the Open Publication License [7].

• Specification -- The technical specification should describe the syntax and semantics of any new language feature. The specification should be detailed enough to allow competing, interoperable implementations for any of the current Bitcoin platforms (Satoshi, BitcoinJ, bitcoin-js, libbitcoin).

• Motivation -- The motivation is critical for BEPs that want to change the Bitcoin protocol. It should clearly explain why the existing protocol specification is inadequate to address the problem that the BEP solves. BEP submissions without sufficient motivation may be rejected outright.

• Rationale -- The rationale fleshes out the specification by describing what motivated the design and why particular design decisions were made. It should describe alternate designs that were considered and related work, e.g. how the feature is supported in other languages.

• The rationale should provide evidence of consensus within the community and discuss important objections or concerns raised during discussion.

• Backwards Compatibility -- All BEPs that introduce backwards incompatibilities must include a section describing these incompatibilities and their severity. The BEP must explain how the author proposes to deal with these incompatibilities. BEP submissions without a sufficient backwards compatibility treatise may be rejected outright.

• Reference Implementation -- The reference implementation must be completed before any BEP is given status "Final", but it need not be completed before the BEP is accepted. It is better to finish the specification and rationale first and reach consensus on it before writing code.

• The final implementation must include test code and documentation appropriate for the Bitcoin protocol.

BEP Formats and Templates

BEPs should be written in mediawiki wiki syntax. Image files should be included in the current subdirectory for that BEP.

BEP Header Preamble

Each BEP must begin with an RFC 822 style header preamble. The headers must appear in the following order. Headers marked with "*" are optional and are described below. All other headers are required.

  BEP: <BEP number>
  Title: <BEP title>
  Author: <list of authors' real names and optionally, email addrs>
* Discussions-To: <email address>
  Status: <Draft | Active | Accepted | Deferred | Rejected |
           Withdrawn | Final | Superseded>
  Type: <Standards Track | Informational | Process>
  Created: <date created on, in dd-mmm-yyyy format>
  Post-History: <dates of postings to bitcoin mailing list>
* Replaces: <BEP number>
* Superseded-By: <BEP number>
* Resolution: <url>

The Author header lists the names, and optionally the email addresses of all the authors/owners of the BEP. The format of the Author header value must be

 Random J. User <address@dom.ain>

if the email address is included, and just

 Random J. User

if the address is not given.

If there are multiple authors, each should be on a separate line following RFC 2822 continuation line conventions.

Note: The Resolution header is required for Standards Track BEPs only. It contains a URL that should point to an email message or other web resource where the pronouncement about the BEP is made.

While a BEP is in private discussions (usually during the initial Draft phase), a Discussions-To header will indicate the mailing list or URL where the BEP is being discussed. No Discussions-To header is necessary if the BEP is being discussed privately with the author, or on the bitcoin email mailing lists.

The Type header specifies the type of BEP: Standards Track, Informational, or Process.

The format of a BEP is specified with a Content-Type header. The acceptable values are "text/plain" for plaintext BEPs (see BEP 9 [3]) and "text/x-rst" for reStructuredText BEPs (see BEP 12 [4]). Plaintext ("text/plain") is the default if no Content-Type header is present.

The Created header records the date that the BEP was assigned a number, while Post-History is used to record the dates of when new versions of the BEP are posted to bitcoin mailing lists. Both headers should be in dd-mmm-yyyy format, e.g. 14-Aug-2001.

BEPs may have a Requires header, indicating the BEP numbers that this BEP depends on.

BEPs may also have a Superseded-By header indicating that a BEP has been rendered obsolete by a later document; the value is the number of the BEP that replaces the current document. The newer BEP must have a Replaces header containing the number of the BEP that it rendered obsolete. Auxiliary Files

BEPs may include auxiliary files such as diagrams. Such files must be named BEP-XXXX-Y.ext, where "XXXX" is the BEP number, "Y" is a serial number (starting at 1), and "ext" is replaced by the actual file extension (e.g. "png").

Transferring BEP Ownership

It occasionally becomes necessary to transfer ownership of BEPs to a new champion. In general, we'd like to retain the original author as a co-author of the transferred BEP, but that's really up to the original author. A good reason to transfer ownership is because the original author no longer has the time or interest in updating it or following through with the BEP process, or has fallen off the face of the 'net (i.e. is unreachable or not responding to email). A bad reason to transfer ownership is because you don't agree with the direction of the BEP. We try to build consensus around a BEP, but if that's not possible, you can always submit a competing BEP.

If you are interested in assuming ownership of a BEP, send a message asking to take over, addressed to both the original author and the BEP editor <BEPs@python.org>. If the original author doesn't respond to email in a timely manner, the BEP editor will make a unilateral decision (it's not like such decisions can't be reversed :). BEP Editor Responsibilities & Workflow

A BEP editor must subscribe to the <BEPs@python.org> list. All BEP-related correspondence should be sent (or CC'd) to <BEPs@python.org> (but please do not cross-post!).

For each new BEP that comes in an editor does the following:

• Read the BEP to check if it is ready: sound and complete. The ideas must make technical sense, even if they don't seem likely to be accepted.
• The title should accurately describe the content.
• Edit the BEP for language (spelling, grammar, sentence structure, etc.), markup (for reST BEPs), code style (examples should match BEP 8 & 7).

If the BEP isn't ready, the editor will send it back to the author for revision, with specific instructions.

Once the BEP is ready for the repository, the BEP editor will:

• Assign a BEP number (almost always just the next available number, but sometimes it's a special/joke number, like 666 or 3141).

• List the BEP in BEP 0 (in two places: the categorized list, and the numeric list).

• Add the BEP to git. For git repository instructions, see the FAQ for Developers.

• Monitor bitcoin.org to make sure the BEP gets added to the site properly.

• Send email back to the BEP author with next steps (post to python-list & -dev).

Many BEPs are written and maintained by developers with write access to the Bitcoin codebase. The BEP editors monitor BEP changes, and correct any structure, grammar, spelling, or markup mistakes we see.

The editors don't pass judgement on BEPs. We merely do the administrative & editorial part. Except for times like this, there's relatively low volume.