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IntersectMBO/cardano-ledger

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The ledger implementation and specifications of the Cardano blockchain.

Is IntersectMBO/cardano-ledger beginner-friendly?

In the last 30 days, IntersectMBO/cardano-ledger merged 35 of 47 pull requests from outside contributors, and its maintainers usually reply within 5 days. 3 beginner-friendly issues are open now.

Stars
295
Forks
179
Open beginner issues
3
Indexed issues
262
Avg merge
6d 4h
Merged PRs (30d)
41
Dominant language
Haskell
License
Apache-2.0
Last GitHub push
Sep 19, 2026
Latest indexed
Sep 17, 2026
Contributing guide
Code of conduct
Beginner labels
help wanted

How to contribute to IntersectMBO/cardano-ledger

  1. Read the contributing guide first: it says how the maintainers want changes proposed, tested and reviewed.
  2. Read its code of conduct: it covers issues and pull requests as well as chat.
  3. Your contributions will be published under the project's Apache-2.0 license.
  4. Pick one of the 3 open beginner-friendly issues below and comment that you want to work on it before you start.
Beginner friendly Everything
Open All

Issues somebody may already be working on are listed last. List everything by date

  • Follow up tests to TxInfo integration
    Open
    • Is something wrong?
    :detective: testing plutus

    Difficulty 4/5 3-5 days Newbie friendliness 52/100

    IntersectMBO/cardano-ledger#6113 · 1 assignee ·

    Maintainers usually reply within 5 days

  • Add a CI check that prevents SRPs for non-approved repos
    Open
    • Is something wrong?
    :hammer_and_wrench: infrastructure maintenance

    Difficulty 3/5 1-2 days Newbie friendliness 50/100

    IntersectMBO/cardano-ledger#6105 ·

    Maintainers usually reply within 5 days

  • Simplify serialization of predicate failures once in Dijkstra
    Open
    • Is something wrong?
    :credit_card: technical-debt

    Difficulty 3/5 1-2 days Newbie friendliness 65/100

    IntersectMBO/cardano-ledger#6100 ·

    Maintainers usually reply within 5 days

  • Consistent naming for block headers
    Open
    • Is something wrong?
    :cake: good first issue :credit_card: technical-debt

    Difficulty 5/5 Over a week Newbie friendliness 35/100

    IntersectMBO/cardano-ledger#6098 ·

    Maintainers usually reply within 5 days

  • `EraBlockHeader` interface in presence of Peras
    Open
    • Is something wrong?
    DijkstraEra Peras

    Difficulty 4/5 3-5 days Newbie friendliness 48/100

    IntersectMBO/cardano-ledger#6097 ·

    Maintainers usually reply within 5 days

  • Ensure epochNo for BlsKey update is recorded correctly
    Open
    • Is something wrong?

    Difficulty 4/5 3-5 days Newbie friendliness 45/100

    IntersectMBO/cardano-ledger#6079 · 1 comment ·

    Maintainers usually reply within 5 days

  • Hide `VMap` constructor
    Open
    • Is something wrong?
    :cake: good first issue :credit_card: technical-debt

    Difficulty 3/5 1-2 days Newbie friendliness 64/100

    IntersectMBO/cardano-ledger#6078 ·

    Maintainers usually reply within 5 days

  • `getRatifyEnv` does not account for proposal deposits
    Open
    • Is something wrong?
    :detective: testing bug

    Difficulty 3/5 1-2 days Newbie friendliness 55/100

    IntersectMBO/cardano-ledger#6069 ·

    Maintainers usually reply within 5 days

  • Fix Imp fixup for Plutus scripts in subtransactions
    Open
    • Is something wrong?
    :detective: testing DijkstraEra

    Difficulty 3/5 1-2 days Newbie friendliness 55/100

    IntersectMBO/cardano-ledger#6057 ·

    Maintainers usually reply within 5 days

  • Prevent duplicate BlsKey from being used
    Open
    • Is something wrong?
    DijkstraEra Leios Peras

    Difficulty 3/5 1-2 days Newbie friendliness 48/100

    IntersectMBO/cardano-ledger#6035 ·

    Maintainers usually reply within 5 days

  • Remove `PParams` from `SnapEnv`
    Open
    • Is something wrong?
    :cake: good first issue :credit_card: technical-debt

    Difficulty 2/5 1-3 hours Newbie friendliness 68/100

    IntersectMBO/cardano-ledger#6027 ·

    Maintainers usually reply within 5 days

  • Unsound duplicate VRF checks introduced in Van Rossem?
    May be free again Open
    • Is something wrong?
    bug DijkstraEra

    IntersectMBO/cardano-ledger#6016 · 4 comments · 1 reaction · 1 assignee ·

    Maintainers usually reply within 5 days

  • Seed stake snapshots in testnet setups
    Open
    • Is something wrong?
    :credit_card: technical-debt

    Difficulty 4/5 3-5 days Newbie friendliness 48/100

    IntersectMBO/cardano-ledger#5996 · 1 reaction ·

    Maintainers usually reply within 5 days

  • Test `TimeTranslationPastHorizon`
    Open
    • Is something wrong?
    :detective: testing

    Difficulty 2/5 1-3 hours Newbie friendliness 70/100

    IntersectMBO/cardano-ledger#5994 ·

    Maintainers usually reply within 5 days

  • Ledger Consensus interface for EBs
    Open
    • Is something wrong?

    Difficulty 5/5 Over a week Newbie friendliness 10/100

    IntersectMBO/cardano-ledger#5982 ·

    Maintainers usually reply within 5 days

  • Remove `GovActionIx` in favor of `TxIx`
    Open
    • Is something wrong?
    :cake: good first issue :credit_card: technical-debt

    Difficulty 3/5 1-2 days Newbie friendliness 55/100

    IntersectMBO/cardano-ledger#5972 ·

    Maintainers usually reply within 5 days

  • Turn `StakePoolParams` into a type family
    Open
    • Is something wrong?

    Difficulty 5/5 Over a week Newbie friendliness 35/100

    IntersectMBO/cardano-ledger#5963 ·

    Maintainers usually reply within 5 days

  • CIP-23 Fair Min Fees
    Open
    • Is something wrong?
    DijkstraEra intra-era-hardfork

    Difficulty 4/5 3-5 days Newbie friendliness 48/100

    IntersectMBO/cardano-ledger#5954 ·

    Maintainers usually reply within 5 days

  • Golden tests for `examplePParams` and `examplePParamsUpdate`
    Open
    • Is something wrong?
    :cake: good first issue :detective: testing

    Difficulty 3/5 1-2 days Newbie friendliness 68/100

    IntersectMBO/cardano-ledger#5936 ·

    Maintainers usually reply within 5 days

  • Integrate PlutusV4 context
    May be free again Open
    • Is something wrong?
    CIP-112 - Guard Script Type CIP-118 - Nested Transactions CIP-159 - Account Address Enhancement DijkstraEra plutus

    IntersectMBO/cardano-ledger#5925 · 1 assignee ·

    Maintainers usually reply within 5 days

  • Move UTxO modules under `[Era].State.UTxO` umbrella
    Open
    • Is something wrong?
    :cake: good first issue :credit_card: technical-debt

    Difficulty 4/5 3-5 days Newbie friendliness 52/100

    IntersectMBO/cardano-ledger#5921 ·

    Maintainers usually reply within 5 days

  • Test that deposits/refunds from certificates for Dijkstra
    Open
    • Is something wrong?
    :detective: testing DijkstraEra

    Difficulty 4/5 3-5 days Newbie friendliness 45/100

    IntersectMBO/cardano-ledger#5901 ·

    Maintainers usually reply within 5 days

  • Inconsistent behavior wrt registration of hot credentials and voting for possible future CC members in PV >= 11
    Open
    • Is something wrong?
    DijkstraEra intra-era-hardfork

    Difficulty 4/5 3-5 days Newbie friendliness 45/100

    IntersectMBO/cardano-ledger#5898 ·

    Maintainers usually reply within 5 days

  • Confusing DecoderErrorSizeMismatch error message / flipped arguments
    Open
    • Is something wrong?
    :cake: good first issue :credit_card: technical-debt

    Difficulty 1/5 Under an hour Newbie friendliness 85/100

    IntersectMBO/cardano-ledger#5886 ·

    Maintainers usually reply within 5 days

  • Move `ChainChecks` into tests
    Open
    • Is something wrong?
    :cake: good first issue :credit_card: technical-debt

    Difficulty 3/5 1-2 days Newbie friendliness 64/100

    IntersectMBO/cardano-ledger#5856 ·

    Maintainers usually reply within 5 days

  • Consistent qualified imports
    Open
    • Is something wrong?

    Difficulty 4/5 3-5 days Newbie friendliness 48/100

    IntersectMBO/cardano-ledger#5835 ·

    Maintainers usually reply within 5 days

  • Generator for MaryValue can generate out-of-bounds failing round-trip test
    Open
    • Is something wrong?
    :detective: testing :slot_machine: property test cddl generator quality

    Difficulty 3/5 1-2 days Newbie friendliness 55/100

    IntersectMBO/cardano-ledger#5833 · 2 comments ·

    Maintainers usually reply within 5 days

  • There are no externally visible orphans `Cardano.Ledger.[Era].Rules` modules.
    Open
    • Is something wrong?
    :cake: good first issue :credit_card: technical-debt

    Difficulty 3/5 1-2 days Newbie friendliness 64/100

    IntersectMBO/cardano-ledger#5825 ·

    Maintainers usually reply within 5 days

  • `BabbageTxOut` CDDL CI failure
    May be free again Open
    • Is something wrong?
    :detective: testing

    IntersectMBO/cardano-ledger#5820 · 1 assignee ·

    Maintainers usually reply within 5 days

  • Streaming injection into LedgerHD
    May be free again Open
    • Is something wrong?
    :floppy_disk: LedgerHD

    IntersectMBO/cardano-ledger#5800 · 1 assignee ·

    Maintainers usually reply within 5 days

  • BUG: `queryStakeSnapshots` returns `ssSetTotal = 1` / `ssGoTotal = 1` for empty snapshots instead of `0`
    Open
    • Is something wrong?
    :cake: good first issue

    Difficulty 4/5 3-5 days Newbie friendliness 58/100

    IntersectMBO/cardano-ledger#5788 · 3 comments ·

    Maintainers usually reply within 5 days

  • Minor collection of fixes needed for Dijkstra
    Open
    • Is something wrong?
    :cake: good first issue :credit_card: technical-debt DijkstraEra

    Difficulty 2/5 1-3 hours Newbie friendliness 55/100

    IntersectMBO/cardano-ledger#5771 ·

    Maintainers usually reply within 5 days

  • Imp tests for `WithdrawalsExceedAccountBalance`
    Open
    • Is something wrong?
    :detective: testing

    Difficulty 4/5 3-5 days Newbie friendliness 45/100

    IntersectMBO/cardano-ledger#5769 ·

    Maintainers usually reply within 5 days

  • Switch previous `PParams` to previous `ProtVer`
    Open
    • Is something wrong?
    :cake: good first issue

    Difficulty 4/5 3-5 days Newbie friendliness 45/100

    IntersectMBO/cardano-ledger#5759 ·

    Maintainers usually reply within 5 days

  • Increase test-coverage for queries
    Open
    • Is something wrong?
    :credit_card: technical-debt :detective: testing :slot_machine: property test cddl ledger-state-query maintenance serialization

    Difficulty 5/5 Over a week Newbie friendliness 35/100

    IntersectMBO/cardano-ledger#5722 · 1 comment ·

    Maintainers usually reply within 5 days

  • Stop using `Coders` for onchain data decoding
    May be free again Open
    • Is something wrong?
    DijkstraEra serialization

    IntersectMBO/cardano-ledger#5718 · 1 assignee ·

    Maintainers usually reply within 5 days

  • Automatically report flaky tests via CI
    May be free again Open
    • Is something wrong?
    :detective: testing :hammer_and_wrench: infrastructure

    IntersectMBO/cardano-ledger#5714 · 1 assignee ·

    Maintainers usually reply within 5 days

  • Ledger state query for number of stake pool delegations
    Open
    • Is something wrong?
    :cake: good first issue enhancement

    Difficulty 4/5 3-5 days Newbie friendliness 52/100

    IntersectMBO/cardano-ledger#5698 ·

    Maintainers usually reply within 5 days

  • Avoid rebuilding for doctests
    May be free again Open
    • Is something wrong?
    :credit_card: technical-debt

    IntersectMBO/cardano-ledger#5685 · 2 comments · 1 assignee ·

    Maintainers usually reply within 5 days

  • Make doctests work with ghc-9.14
    Open
    • Is something wrong?

    Difficulty 3/5 1-2 days Newbie friendliness 55/100

    IntersectMBO/cardano-ledger#5680 · 1 comment ·

    Maintainers usually reply within 5 days

  • Add conformance for UTXOS rule
    Open
    • Is something wrong?
    :detective: testing conformance ConwayEra

    Difficulty 4/5 3-5 days Newbie friendliness 45/100

    IntersectMBO/cardano-ledger#5678 ·

    Maintainers usually reply within 5 days

  • Define Huddle spec for all ledger state queries
    May be free again Open
    • Is something wrong?
    cddl ledger-state-query

    IntersectMBO/cardano-ledger#5661 · 1 comment · 1 assignee ·

    Maintainers usually reply within 5 days

  • Define result types for all ledger state queries
    May be free again Open
    • Is something wrong?
    :credit_card: technical-debt ledger-state-query

    IntersectMBO/cardano-ledger#5660 · 1 assignee ·

    Maintainers usually reply within 5 days

  • Fail on new features in TxInfo translation
    Open
    • Is something wrong?
    DijkstraEra

    Difficulty 4/5 3-5 days Newbie friendliness 35/100

    IntersectMBO/cardano-ledger#5625 ·

    Maintainers usually reply within 5 days

  • Remove `isValid` from transaction deserialization
    Open
    • Is something wrong?
    cddl EulerEra serialization

    Difficulty 3/5 1-2 days Newbie friendliness 48/100

    IntersectMBO/cardano-ledger#5605 ·

    Maintainers usually reply within 5 days

  • Dijkstra Era
    May be free again Open
    • Is something wrong?
    DijkstraEra

    IntersectMBO/cardano-ledger#5604 · 2 comments · 4 reactions · 1 assignee ·

    Maintainers usually reply within 5 days

  • CIP-112 - Guard Script Type
    May be free again Open
    • Is something wrong?
    CIP-112 - Guard Script Type

    IntersectMBO/cardano-ledger#5603 · 1 assignee ·

    Maintainers usually reply within 5 days

  • Fix CantFollow conformance
    Open
    • Is something wrong?
    :detective: testing conformance

    Difficulty 4/5 3-5 days Newbie friendliness 35/100

    IntersectMBO/cardano-ledger#5601 · 2 comments · 1 reaction ·

    Maintainers usually reply within 5 days

  • Fix the DecShareCBOR instance for StakeWithDelegations
    Open
    • Is something wrong?
    :credit_card: technical-debt enhancement serialization

    Difficulty 3/5 1-2 days Newbie friendliness 35/100

    IntersectMBO/cardano-ledger#5598 ·

    Maintainers usually reply within 5 days

  • When possible, remove un-need allow-newer stanzas for ghc-9.14
    Open
    • Is something wrong?

    Difficulty 4/5 3-5 days Newbie friendliness 35/100

    IntersectMBO/cardano-ledger#5588 ·

    Maintainers usually reply within 5 days

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