Is there any API for this out already?

I'm looking for an API that:

  1. Given a tx hash, can get the block # and info about the block which the transaction was in
  2. get current block # and info about current block

3 Answers 3


Using Blockfrost.io API:

  1. For transaction hash dbbf5116280f83bb6d3d117ef0b41ca52b0bb85f417f761bd42d1903286743e6:

You can find the block height:

 $ curl -s https://cardano-mainnet.blockfrost.io/api/v0/txs/dbbf5116280f83bb6d3d117ef0b41ca52b0bb85f417f761bd42d1903286743e6 -H 'project_id: xxx' \
  | jq .block_height

And use that block height to get more information about the given block.

$ curl -s https://cardano-mainnet.blockfrost.io/api/v0/blocks/8369736 -H 'project_id: x'  | jq
  "time": 1675778106,
  "height": 8369736,
  "hash": "0fa8c39c9c30ebb14b64781cca63d326a3c57154dfb590d63c0d3eb7850cc4ec",
  "slot": 84211815,
  "epoch": 392,
  "epoch_slot": 231015,
  "slot_leader": "pool1q7wrwstqkzhrffdzpw8ftfd4epmxywdjnp8384atjcnezchv242",
  "size": 88902,
  "tx_count": 35,
  "output": "22093283458254",
  "fees": "11180120",
  "block_vrf": "vrf_vk1uatrt2xzhxs382ss5u9mr20aahzx8s000c077xerulzy22dzxy3qc0r6qv",
  "op_cert": "9c6689a625fb22cd17df084718f232155a15a73b56103a96a117e5d4a58f95a8",
  "op_cert_counter": "10",
  "previous_block": "055462536b48a16b91552ff05df0760d2191c044ec419f2f93d9c7a894aaecde",
  "next_block": "f63f3ed7140524bffc1a975a177f93cf72b426201f9ea5a82cb059a7ed1b53df",
  "confirmations": 10
  1. For the current block number, just use /api/v0/blocks/latest.

If you looking for a simple web API, the most popular choice is Blockfrost: https://docs.blockfrost.io/#tag/Cardano-Blocks/paths/~1blocks~1%7Bhash_or_number%7D/get https://docs.blockfrost.io/#tag/Cardano-Blocks/paths/~1blocks~1latest/get

which has a generous free tier. An alternative is Koios: https://api.koios.rest/#overview

If you want to run some infrastructure yourself, have a look at:

Ogmois: https://ogmios.dev/ or Oura: https://github.com/txpipe/oura

specifically to get the latest block/live data and

cardano-db-sync (https://github.com/input-output-hk/cardano-db-sync) or carp (https://github.com/dcSpark/carp)

to query the whole chain.


This is a relatively simple query against cardano-db-sync.

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