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Created Apr 20, 2020
What would you like to do?


format eth2.0-apis/issues/24
    OpenAPI / JSON -- general agreement (?)
        int vs str-int
        bytes (0x vs base64)
    optional SSZ where easy/sensible
    optional protobuf refs (?)
api conversions/CI eth2.0-apis/issues/26
    any updates
bn apis eth2.0-apis/issues/25
    Identifiers in the context of our types (vs. query params)
        /beacon/{id}/resource <- very nice construct, but would require some amount duck-typing


  • JSON primary support
  • SSZ useful
  • proto (bufs) also, but not primary
  • Marin has some approach to convert to different formats (no link/ref?)

JSON issues:

  • integer size: thoughts on int vs string?
    • Jim: uint64 as string. ugly but necessary
    • needs consistency
    • felix: eth1 has 0x (0 = 0x0) and DATA vs QUANTITY types
    • felix: eth1 has 256 bit numbers too
    • felix: have been using json api for long. No complaints about strings
    • felix: api wrappers help a lot here
    • danny: need debugger readability
    • marin: issue on geth to use dec strings instead of hex
    • jim: 0x is regarded as bytes, decimal string makes sense for ints
    • jim: json is not performant anyway, should just look at readability, no hex
    • mamy: hex to native int is much faster. Since utf8 bytes can just be shifted by 4 bits
    • jacek: never seen 0x as byte array, only as big number
    • danny:
      • int is out
      • string dec/hex is in
      • compat eth1 something to consider
      • decide in next 48 hours
      • issue, hash it out

Danny: API conversions in CI:

  • interest in what is in repo and work with it
  • people want to experiment with conversions
  • don't shoot ourselves in the foot with CI


  • thanks protolambda for API collection work and strawman proposal
  • thanks Mikhail


  • lots of different ways to identify objects
  • challenge to get succinct APIs, find right balance
  • lots hinges on beacon state

Resource idea:

  • specify something in context of a beacon state resouce
    • solves validator index issue
    • ducktyping involved


  • words on REST api, try to make it restful, another round of review
  • probable REST is not the best. There are others, like GraphQL.
  • Try to do restful first, continue from there

Danny: form working group to continue forward with iteration on format


  • there are exceptions, e.g. with FFG endpoint
  • may not all fit current REST approach


  • Felix:
    • something we had for long and appreciate, but not made its way back
    • specification really bad
    • ability for realtime events
    • not really abvailable through rest api
  • Danny:
    • stream endpoints in proposal
    • prysm has stream with grpc
    • lighthouse has websockets
    • marin proposed server-side-events
  • Felix:
    • Geth has something (name?)
    • Subscriptions, as if the server was calling a callback method on the client
    • identifier + data
    • Support available
  • Raul: avoid polling
  • Terence:
    • two way streaming
    • beacon node can stream reassignment to validator
  • Felix
    • documentation about subscriptions approach is not good
    • quite a simple protocol, very happy, really easy to implement on top of json rpc
    • works on all transports, except http
  • Jim
    • Streaming preferable
    • But high workload
    • Idea: just a single stream, share notifications
    • E.g. chain splits, reorgs, etc.
    • Efficiency and api endpoint ease
    • Pull when interested as consumer
    • Simpler notification system, less work
  • Mamy
    • Push and pull api
    • GraphQL was designed to do that
  • Jacek
    • GrapQL is advanced feature, not good for low level adoption
  • Danny
    • keep it simple is good
    • when we do discuss these things, highlight as advanced features
  • Prysm
    • Care mostly about supporting streaming at all
    • Flexible in how it is carried out
  • Marin
    • Describes small somewhat stateful server stream approach
      • client asks for events since certain id
    • Jim/Felix: don't want stateful system
    • Felix: want to forget about past event
    • Felix: avoid replay later
    • Marin: clarifies, just as catch-up approach, don't want to miss events
    • Felix: interested now
    • Marin: maybe needs per api discussion
    • Proto: implemented/hacked the buffer approach already, with browser consuming lighthouse testnet data
    • Jacek: concerned about reorgs still
    • Felix: needs to get view of the chain right, display wallet example, quite a few states.
    • Felix: realtime events make it easier, but ensuring state is more difficult
    • Felix: single event stream, just the new blocks, call apis to update local state based on it. More RPC traffic, but easier to get consistent data.
    • Felix: who are we optimizing for? If browser, need to optimize back and forth information

Danny: TODOs

  • decimal/hex string
  • event streaming
  • formation of small working group to hammer out beacon api
  • not addressed validator apis, need to look at block explorers now
  • reopen validator api updates later

Proto: before close, post links of your API projects, interesting

Danny/jacek: advanced innovation

  • Rocketpool is supporting pooling software
  • validator api for advanced setups


  • Endpoint over libp2p to serve api RPC requests?
  • Run everything on single libp2p stack
  • Danny: who as consumer? Some endpoints not to be exposed to random people
  • Zahary: requests could be authenticated. REST or other new endpoints could pose as new exploit vectors
  • Danny: separation of API and p2p is also nice.
  • Felix: went wrong in eth1: only getting to it now with light client functionality
  • Felix: who will use APIs? What if web browsers need it? Same dilemma as eth1, use something as metamask that talks to centralized provider essentially.
  • Felix: how are browsers going to access? Can libp2p help?
  • Felix: suggestion of jacek makes sense
  • Zahary: something that acts as proxy between browser and network
  • Danny: Nimbus team can open issue for standard mapping between API and libp2p

Danny: working group for API endpoints:

  • Mikhail
  • Marin
  • Jim

Danny: working group telegram chat, present something in a week Danny: anybody else is welcome, but keeping small for fast/dynamic progress



16:02:05	 From danny :
16:11:31	 From Mikhail Kalinin : I vote for 0x instead of Base64, it sometimes handy for debugging to mentally convert values. Base64 would make it almost impossible.
16:12:56	 From Tomasz Stanczak : let us not use Base64 please
16:13:01	 From Tomasz Stanczak : losing readability a lot
16:13:52	 From Tomasz Stanczak : hex encoded numbers in Eth1 can be mentally converted to some extent - this helps a lot
16:14:24	 From Tomasz Stanczak : I stand by Felix and Mikhail here
16:14:59	 From Mamy : Base64 is for bytes though, we are talking about integer as stringified int vs hex
16:15:18	 From Mamy : (I agree that Base64 should be avoided)
16:15:27	 From Tomasz Stanczak : ok @Mamy, thanks
16:15:41	 From Mikhail Kalinin : May we end up with the default encoding of ints and keep the other option for those cases where it will be appropriate
16:15:42	 From Felix : V
16:15:43	 From Mamy : bytes serialisation is next i assume ;)
16:15:52	 From Tomasz Stanczak : as for numbers I am less in favour of 0x but it is acceptable
16:15:55	 From Felix :
16:16:07	 From Tomasz Stanczak : but it caused us trouble in Nethermind - some libs are hard ot modify to handle these as numbers
16:16:15	 From Felix : for reference, the eth1 API encoding
16:17:20	 From Tomasz Stanczak : also we started allowing passing ints in decimal in our CLI and Geth is sometimes inconsistent - small numbers are sometimes sent as normal ints (but very rarely and I think it is just some minor technical debt from far in the past)
16:18:00	 From Mamy : Parsing a base 10:
16:18:12	 From Mamy : I didn’t put a shortcut for Hex but it’s significantly faster
16:28:01	 From Mikhail Kalinin : I will be capable of doing the work on API on Thursday or Friday this week.
16:28:32	 From Marin Petrunić : I can also help if needed :)
16:29:55	 From Mikhail Kalinin : That would be great! I am open for any help.
16:30:28	 From Felix :
16:30:56	 From Marin Petrunić : I would just remind that this is pretty standard tehnology with support everywhere:
16:31:13	 From Raul Jordan (Prysmatic) : +1
16:31:43	 From Chih-Cheng Liang : come across this quote, but not sure how to fit in to the current discussion
16:31:45	 From Chih-Cheng Liang : "What is JSON RPC for? Is it a Web API (needs to be 99% available, but not 100% accurate), or database access API (needs to be 100% accurate, but not necessarily 99% available)"
16:36:52	 From Raul Jordan (Prysmatic) : +1, graphql should be optional and not required for client implementers
16:36:54	 From Mike Goldin : Can GraphQL schemas be generated from OpenAPI?
16:37:06	 From Felix Lange : not really
16:37:18	 From Raul Jordan (Prysmatic) :
16:37:26	 From Felix Lange : oh, OK
16:37:31	 From Felix Lange : didn't know that
16:37:33	 From Jim McDonald : Agree that simple here is good, JSON meets that goal and not sure that graphql does
16:50:36	 From Raul Jordan (Prysmatic) :
16:51:33	 From Jim McDonald : talks to prysm nodes today to obtain bits and pieces of information, and has features such as sending voluntary exits.  I stopped work on the API pieces until it standardises, so lots still to do
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