set

Call v101 → current #0

Sets the current on-chain time; called exactly once per block by validators.

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Used by: validatorsdevelopers

The Big Picture

Blockchains have no native concept of time - they only know block numbers. The Timestamp pallet bridges this gap by allowing validators to set the current Unix timestamp in each block. This timestamp becomes the canonical on-chain time used by all other pallets and contracts that need time-based logic.

Why This Matters

Many blockchain operations need real-world time: vesting schedules, auction deadlines, rate limiting windows. The timestamp pallet provides this fundamental infrastructure. You don't call this directly - validators do it automatically as part of block production.

Example Scenario

Every block includes an inherent timestamp extrinsic. At block 1000000, the validator calls set(now=1704067200000) - Unix milliseconds for Jan 1, 2024. Any pallet or contract can now query Timestamp.Now to get 1704067200000.

Common Questions

Can regular users call this?
No. This is an inherent extrinsic with None origin - only the block author (validator) can include it, and they must include it or the block fails.
How accurate is on-chain time?
Reasonably accurate but not precise. Validators use their local clock, and MinimumPeriod prevents going backwards. Expect accuracy within seconds, not milliseconds.
What happens if a validator sets a wrong time?
MinimumPeriod prevents timestamps from going backwards or jumping too little. Consensus mechanisms also constrain allowed time ranges to prevent abuse.

Use Cases

  • Provide on-chain time reference for all block operations
  • Enable time-based logic in smart contracts and pallets
  • Coordinate block timing with consensus mechanism

From Chain Metadata

Set the current time. This call should be invoked exactly once per block. It will panic at the finalization phase, if this call hasn't been invoked by that time. The timestamp should be greater than the previous one by the amount specified by `MinimumPeriod`. The dispatch origin for this call must be `Inherent`. ## Complexity `O(1)` (Note that implementations of `OnTimestampSet` must also be `O(1)`) 1 storage read and 1 storage mutation (codec `O(1)`). (because of `DidUpdate::take` in `on_finalize`) 1 event handler `on_timestamp_set`. Must be `O(1)`.

Input Parameters

#NameTypeDescription
0
now
→ timestamp
Compact<u64> CptUnix timestamp in milliseconds to set as current block time (SCALE compact -> integer)

Permissions

Origin
Unknown
Required Role
Any

Permission data inferred from metadata. May be incomplete.

Requirements

  • Call must originate from None (inherent extrinsic)
  • Must be called exactly once per block
  • Timestamp must be greater than previous by at least MinimumPeriod

Effects

Storage Modified

NowDidUpdate

Postconditions

  • Now storage updated to the new timestamp
  • DidUpdate flag set to true for this block
  • on_timestamp_set hook is triggered

Side Effects

  • Block finalization will panic if this wasn't called
  • Other pallets may react to timestamp changes via on_timestamp_set

Code Examples

import { ApiPromise, WsProvider } from "@polkadot/api";
import { stringCamelCase } from "@polkadot/util";

const provider = new WsProvider("wss://entrypoint-finney.opentensor.ai:443");
const api = await ApiPromise.create({ provider });

// Build set call
const now = 0;

const call = api.tx[stringCamelCase("Timestamp")][stringCamelCase("set")](
  now
);

On-Chain Activity

Usage Frequency
●●●●●○ Core 1M–10M extrinsics

Primary protocol calls

#6 most used call

Success Rate Near-certain

Over 95% of submissions succeed

As of block 7,429,232

Runtime Info

Pallet Index
2
Call Index
0
First Version
v101
Current Version
v393
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