serve_axon

Call v101 → v277, v290 → current #4

Registers axon server endpoint for a neuron .

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Call Workflow

serve_axon

1. Validation

Signature, nonce, mortality, fees

Signature

Nonce

Mortality

Fee payment

2. Pre-dispatch

Permission & state checks

Permission checks

State validation

3. Dispatch

Execute logic, modify state

AxonServed Axons LastTxBlock

4. Post-dispatch

Final result & fee settlement

ExtrinsicSuccess

Fees settled

Svelte Flow

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Used by: minersvalidatorsdevelopers

The Big Picture

Your axon is your miner's public API. Validators need to know where to send queries, and this call publishes that address on-chain. Without a served axon, validators can't reach you, and you can't earn.

Why This Matters

Registration gets you a UID. Serving your axon tells the network where to find you. Both are required to actually receive queries and earn emissions.

Example Scenario

Your miner runs at 203.0.113.50:8091. After registering on subnet 1, call serve_axon(netuid=1, ip=203.0.113.50, port=8091). Now validators can discover and query your miner.

Common Questions

Do I need to update my axon if my IP changes?: Yes! If validators can't reach you, you get zero scores. Serve again with your new IP.
What about firewalls?: Ensure your axon port is publicly accessible. The chain just stores the address - you're responsible for actually being reachable.

Use Cases

Publish your miner's API endpoint
Update your endpoint after IP change
Make your neuron discoverable for queries

From Chain Metadata

Serves or updates axon /prometheus information for the neuron associated with the caller. If the caller is already registered the metadata is updated. If the caller is not registered this call throws NotRegistered.

Input Parameters

#	Name	Type	Description
0	netuid	u16 NetUid	netuid: Subnet ID (u16, 0-65535)
1	version	u32	version (u32)
2	ip	u128	ip (u128)
3	port	u16	port (u16)
4	ip_type	u8	ip_type (u8)
5	protocol	u8	protocol (u8)
6	placeholder1	u8	placeholder1 (u8)
7	placeholder2	u8	placeholder2 (u8)

Permissions

Origin

Signed

Required Role

Hotkey

Authorization Checks

Hotkey must be registered on the target subnet

Requirements

Caller is registered on subnet
Valid IP/port provided
Serving not rate limited

Effects

Events Emitted

AxonServed

Storage Modified

Axons LastTxBlock

Postconditions

Axon endpoint stored

Side Effects

Other neurons can discover endpoint
Validators can send requests

Code Examples

import { createClient, Binary } from "polkadot-api";
import { getWsProvider } from "polkadot-api/ws";
import { sub } from "@polkadot-api/descriptors"; // generated by: npx papi add sub -w wss://entrypoint-finney.opentensor.ai:443

const client = createClient(getWsProvider("wss://entrypoint-finney.opentensor.ai:443"));
const api = client.getTypedApi(sub);

// Build serve_axon call (typed, named args)
const netuid = 1;
const version = 0;
const ip = 0n;
const port = 0;
const ip_type = 0;
const protocol = 0;
const placeholder1 = 0;
const placeholder2 = 0;

const tx = api.tx.SubtensorModule.serve_axon({
  netuid,
  version,
  ip,
  port,
  ip_type,
  protocol,
  placeholder1,
  placeholder2,
});

On-Chain Activity

Usage Frequency

●●●●●● Dominant >10M extrinsics

Highest-volume operations

#3 most used call

Success Rate Competitive

5–20% of submissions succeed — expect frequent failures

As of block 7,429,232

Version History

Version:

v101 block 1 8 args

v290 block 5,947,548 8 args Current

Runtime Info

View Source

Pallet Index: 7
Call Index: 4
First Version: v101
Current Version: v411

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