> ## Documentation Index
> Fetch the complete documentation index at: https://docs.bloklake.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Robinhood Chain

> Robinhood Chain (an Arbitrum Orbit L2): URLs, finality, Arbitrum fields and quirks.

| | |
| - | - |
| Name in URLs | `rh` |
| Base URL | `https://api.bloklake.com/v1/chains/rh` (or `https://rh.api.bloklake.com`) |
| Chain id | `4663` |
| Block time | about 100 ms (10 blocks per second) |
| Served from | block 0 (genesis) |
| Finality | 64 blocks behind the head (about 6–7 seconds) |
| Field families | base + Arbitrum |

## Fast blocks, more blocks

At ten blocks per second, Robinhood Chain produces about 864,000 blocks a day. Two things
follow:

* **Ranges are long.** A day is about 864,000 blocks, so a one-day query spans about 18
  responses at the 50,000-block page limit, even if it matches few rows. Your
  [pagination loop](https://docs.bloklake.com/querying/pagination.md) handles this; just don't be surprised by the page
  count.
* **Blocks are small.** A block holds a few dozen transactions at most, and there are no empty
  blocks: each one has the ArbOS system transaction (below) and at least one user transaction.

## The ArbOS system transaction

Every Robinhood Chain block starts with an ArbOS "start block" transaction: type `0x6a`, sent
from `0x00000000000000000000000000000000000a4b05`. A query for every transaction in a range
returns one of these per block (except block 0, the genesis block, which has no transactions).
A few blocks carry more than one, for example the batch-posting reports. To leave them out,
filter on `type`: `"type": [0, 1, 2, 4]` keeps ordinary signed transactions and leaves out
ArbOS's type `106` (and Arbitrum's other system and retryable types). Or filter on
`to`/`from`/`sighash` so they never match.

## Arbitrum fields

On top of the base fields, Robinhood Chain fills these:

| Row type | Fields |
| - | - |
| blocks | `l1BlockNumber`, `sendCount`, `sendRoot` |
| transactions (receipt) | `gasUsedForL1`, `l1BlockNumber`, `timeboosted` |
| transactions (retryable and system types) | `requestId`, `ticketId`, `refundTo`, `maxRefund`, `submissionFeeRefund`, `depositValue`, `retryTo`, `retryValue`, `retryData`, `beneficiary`, `maxSubmissionFee`, `l1BaseFee` |

The retryable fields are `null` on transaction types that don't carry them. The six amounts
(`maxRefund`, `submissionFeeRefund`, `depositValue`, `retryValue`, `maxSubmissionFee`,
`l1BaseFee`) are full 256-bit values: 32 bytes big-endian in Arrow, decimal strings in JSON. A
`maxRefund` of 2²⁵⁶ − 1 ("unlimited") is 32 bytes of `0xff`. See
[Data types](https://docs.bloklake.com/responses/data-types.md).

`timeboosted` is `1` when the transaction went through the Timeboost express lane. It is `null`
when the chain's nodes don't report it, which is the case today.

## Fields Robinhood Chain doesn't have

Arbitrum chains don't produce withdrawals, blobs or the Prague block fields. These are always
`null` and listed in `unavailable_fields`:

* blocks: `totalDifficulty`, `withdrawalsRoot`, `withdrawals`, `blobGasUsed`, `excessBlobGas`,
  `parentBeaconBlockRoot`, `requestsHash`
* transactions: `maxFeePerBlobGas`, `blobVersionedHashes`, `blobGasUsed`, `blobGasPrice`

OP-Stack fields are also `null`.

## Finality

A block is final once 64 newer blocks exist, about 6–7 seconds. Rows above `finalized_block` can
be replaced by a reorg. See [Finality and reorgs](https://docs.bloklake.com/querying/finality-and-reorgs.md).

## Example: every ERC-20 transfer in 10 blocks

```bash theme={null}
curl https://api.bloklake.com/v1/chains/rh/query/json \
  -H "Authorization: Bearer $BLOKLAKE_API_KEY" -H 'content-type: application/json' \
  -d '{"fromBlock": 61000000, "toBlock": 61000009,
       "logs": [{"topic0": ["0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"]}],
       "fields": {"log": {"blockNumber": true, "address": true, "topic1": true, "topic2": true, "data": true}}}'
```

About 500 rows, 160 KB of JSON.


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