# Steem Developer Portal

### Understanding Dynamic Global Properties

Maintains global state information

### Intro

Dynamic Global Properties represents a set of values that are calculated during normal chain operations and reflect the current values of global blockchain properties.

The API returns an object containing information that changes every block interval such as the head block number, the total vesting fund, etc.

### Sections

- Fields
  - head_block_number
  - head_block_id
  - time
  - current_witness
  - total_pow
  - num_pow_witnesses
  - virtual_supply
  - current_supply
  - current_sbd_supply
  - total_vesting_fund_steem
  - total_vesting_shares
  - total_reward_fund_steem
  - total_reward_shares2
  - sbd_interest_rate
  - maximum_block_size
  - current_aslot
  - recent_slots_filled
  - last_irreversible_block_num
  - vote_power_reserve_rate
  - average_block_size
  - current_reserve_ratio
  - max_virtual_bandwidth
- Not Covered
- Example Method Call
- Example Output

### `head_block_number`

Block height at the head of the blockchain. This represents the latest block produced by witnesses.

- example: `24155032`

### `head_block_id`

Used to implement TaPoS (Transaction as Proof of Stake). The first 4 bytes (8 hex digits) of the block ID represents the block number. E.g., `01709398` in hex is `24155032` in decimal.

- example: `0170939865fa4e3aa7fca8f8df35d23333fe0bee`
- see: RIPEMD-160 hashes

### `time`

Point in time (UTC) that the block was included in the chain.

Used to synchronize events like Hard Fork activation.

When attempting to calculate the validity of a transaction we need to lookup a past block and check its block hash and the time it occurred so we can calculate whether the current transaction is valid and at what time it should expire.

For new transactions, expirations originate from this time.

- example: `2018-07-14T01:19:51`

### `current_witness`

Account name of the current witness.

- example: `blocktrades`

### `total_pow` Deprecated

The total POW accumulated, aka the sum of `num_pow_witness` at the time new POW is added.

- example: `514415`

### `num_pow_witnesses` Deprecated

The current count of how many pending POW witnesses there are, determines the difficulty of doing pow.

- example: `172`

### `virtual_supply`

The virtual supply is the supply of all STEEM + all SBD if all SBD were converted to STEEM at the current median price.

- example: `283290592.652 STEEM`

### `current_supply`

STEEM currently in existence.

- example: `271546371.129 STEEM`

### `confidential_supply`

Total asset held in confidential balances.

- example: `0.000 STEEM`

### `current_sbd_supply`

SBD currently in existence.

- example: `15478883.968 SBD`

### `confidential_sbd_supply`

Total asset held in confidential balances.

- example: `0.000 SBD`

### `total_vesting_fund_steem` Deprecated

Now deprecated way to get STEEM that is invested in STEEM POWER (powered up).

Use `condenser_api.get_reward_fund` instead.

- example: `192713261.007 STEEM`

### `total_vesting_shares`

VESTS that are invested in STEEM POWER (powered up).

- example: `390950506702.452773 VESTS`

### `total_reward_fund_steem`

STEEM available in the reward pool.

- example: `0.000 STEEM`

### `total_reward_shares2` Deprecated

Now deprecated way to get the number of shares in the pool.

Use `condenser_api.get_reward_fund` instead.

- example: `0`

### `sbd_interest_rate`

This property defines the interest rate that SBD deposits receive.

- example: `0`

### `maximum_block_size`

Maximum block size is decided by the set of active witnesses which change every round. Each witness posts what they think the maximum size should be as part of their witness properties, the median size is chosen to be the maximum block size for the round.

Note: the minimum value for `maximum_block_size` is defined by the protocol to prevent the network from getting stuck by witnesses attempting to set this too low.

- example: `65536`

### `current_aslot`

The current absolute slot number. Equal to the total number of slots since genesis. Also equal to the total number of missed slots plus `head_block_number`.

- example: `24231997`

### `recent_slots_filled`

Used to compute witness participation.

- example: `340282366920938463463374607431768211455`

### `last_irreversible_block_num`

The latest block number that has been confirmed by two thirds of all block producers and is thus irreversible.

- example: `24155017`

### `vote_power_reserve_rate`

The number of votes regenerated per day. Any user voting slower than this rate will be “wasting” voting power through spillover; any user voting faster than this rate will have their votes reduced.

- example: `10`

### `average_block_size` Removed

Removed in 0.20.6, see: #3029

Average block size is updated every block to be: `average_block_size = (99 * average_block_size + new_block_size) / 100`. This property is used to update the `current_reserve_ratio` to maintain approximately * 50% or less utilization of network capacity.

- example: `9309`

### `current_reserve_ratio` Removed

Removed in 0.20.6, see: #3029

Any time `average_block_size <= 50% maximum_block_size` this value grows by 1 until it reaches `STEEM_MAX_RESERVE_RATIO`. Any time `average_block_size` is greater than 50% it falls by 1%. Upward adjustments happen once per round, downward adjustments happen every block.

- example: `200000000`

### `max_virtual_bandwidth` Removed

Removed in 0.20.6, see: #3029

The maximum bandwidth the blockchain can support is `max_bandwidth = maximum_block_size * STEEM_BANDWIDTH_AVERAGE_WINDOW_SECONDS / STEEM_BLOCK_INTERVAL`; The maximum virtual bandwidth is: `max_bandwidth * current_reserve_ratio`

- example: `264241152000000000000`

### `Not Covered`

Fields not covered in this recipe are:

- `confidential_supply`
- `confidential_sbd_supply`
- `pending_rewarded_vesting_shares`
- `pending_rewarded_vesting_steem`
- `sbd_print_rate`
- `participation_count`

### Example Method Call

To retrieve the current results for `condenser_api.get_dynamic_global_properties`, we can retrieve the current state information using `curl`:

    curl -s --data '{"jsonrpc":"2.0", "method":"condenser_api.get_dynamic_global_properties", "params":[], "id":1}' https://api.steemit.com

### Example Output

    {
       "id":1,
       "jsonrpc":"2.0",
       "result":{
          "head_block_number":24238248,
          "head_block_id":"0171d8a833dc369abd034b0c67d8725f96df9e5b",
          "time":"2018-07-16T22:41:24",
          "current_witness":"xeldal",
          "total_pow":514415,
          "num_pow_witnesses":172,
          "virtual_supply":"283434761.199 STEEM",
          "current_supply":"271729171.190 STEEM",
          "confidential_supply":"0.000 STEEM",
          "current_sbd_supply":"15498201.173 SBD",
          "confidential_sbd_supply":"0.000 SBD",
          "total_vesting_fund_steem":"192913644.627 STEEM",
          "total_vesting_shares":"391296886352.617261 VESTS",
          "total_reward_fund_steem":"0.000 STEEM",
          "total_reward_shares2":"0",
          "pending_rewarded_vesting_shares":"379159224.860656 VESTS",
          "pending_rewarded_vesting_steem":"185294.019 STEEM",
          "sbd_interest_rate":0,
          "sbd_print_rate":2933,
          "maximum_block_size":65536,
          "current_aslot":24315228,
          "recent_slots_filled":"340282366920938463463374607431768211400",
          "participation_count":128,
          "last_irreversible_block_num":24238230,
          "vote_power_reserve_rate":10
       }
    }