Axons

Storage Map v101 → v411 Changed in v411

Axon server info for neurons.

Queried by: minersvalidatorsdeveloperssubnet owners

The Big Picture

Axons are how neurons expose their services to the network. When validators want to query miners for inference (or any subnet-specific task), they look up the miner's Axon to get the IP/port. This is the discovery layer that makes Bittensor's machine learning marketplace actually work.

Why This Matters

You want to query a miner? You need their endpoint. Axons tell you where each neuron lives on the internet - IP address, port, and protocol version. Essential for any validator or client.

Example Scenario

Query Axons(netuid=1, uid=47) returns { ip: '1.2.3.4', port: 8091, ip_type: 4, version: 670, protocol: 4, placeholder1: 0, placeholder2: 0 }. Connect to 1.2.3.4:8091 to reach this miner.

Common Questions

What if Axon shows 0.0.0.0?: The neuron hasn't set their serving info, or is intentionally not serving. They won't receive queries and may have lower performance scores.
How do I update my Axon?: Use the serve_axon extrinsic to update your endpoint info. Subject to ServingRateLimit.
What's the version field?: Protocol version for compatibility. Validators may reject connections from outdated versions.
Is there a rate limit on updates?: Yes, check ServingRateLimit for how often you can update your Axon info.

Use Cases

Connect to a miner's inference endpoint
Build service discovery for subnet clients
Monitor which neurons are actively serving
Debug connectivity issues between neurons
Create subnet health dashboards showing online neurons

From Chain Metadata

MAP ( netuid, hotkey ) --> axon_info

Purpose & Usage

Purpose

Store endpoint information (IP, port, protocol) for neuron communication.

Common Query Patterns

Query by netuid-uid for a specific neuron's endpoint
Iterate all to discover available services
Verify neuron is serving before queries

Query Keys

#	Name	Type	Description
1	netuid	u16	netuid (u16, hashed key component)
2	hotkey	AccountId	hotkey (AccountId, hashed key component) (hex -> SS58)

Stored Value

AxonInfo

axon_info (AxonInfo)

Relationships

Modified By

serve_axon serve_axon_tls swap_hotkey

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);

// Query Axons storage
const netuid = 1;
const hotkey = "5GrwvaEF5zXb26Fz9rcQpDWS57CtERHpNehXCPcNoHGKutQY";

const result = await api.query.SubtensorModule.Axons.getValue(netuid, hotkey);
console.log("Axons:", result);

On-Chain Activity

Write Frequency

●●●●●○ High 1M–10M est. writes

1M–10M estimated writes

#22 most written storage item

Write Source User Extrinsics

Modified via user-submitted extrinsics

As of block 7,429,232

Version History

Version:

v101 block 1 Added

v120 block 315,568 Internal re-bind

v123 block 720,235 Internal re-bind

v128–v132 · runtime versions skipped on chain (never deployed)

v133 block 1,404,224 Internal re-bind

v136 block 1,756,781 Internal re-bind

v138 block 1,907,363 Internal re-bind

v140 block 1,929,216 Internal re-bind

v146 block 2,848,978 Internal re-bind

v149 block 3,014,339 Internal re-bind

v154 block 3,308,611 Internal re-bind

v166–v194 · runtime versions skipped on chain (never deployed)

v195 block 3,791,350 Internal re-bind

v202 block 3,848,823 Internal re-bind

v207–v209 · runtime versions skipped on chain (never deployed)

v210 block 4,345,556 Internal re-bind

v213–v215 · runtime versions skipped on chain (never deployed)

v216 block 4,510,996 Internal re-bind

v220–v232 · runtime versions skipped on chain (never deployed)

v233 block 4,920,350 Internal re-bind

v235–v237 · runtime versions skipped on chain (never deployed)

v238 block 4,936,550 Internal re-bind

v241–v243 · runtime versions skipped on chain (never deployed)

v244 block 4,999,897 Internal re-bind

v266–v272 · runtime versions skipped on chain (never deployed)

v273 block 5,659,032 Internal re-bind

v275–v275 · runtime versions skipped on chain (never deployed)

v276 block 5,781,672 Internal re-bind

v278–v289 · runtime versions skipped on chain (never deployed)

v290 block 5,947,548 Internal re-bind

v293–v296 · runtime versions skipped on chain (never deployed)

v297 block 6,067,943 Internal re-bind

v307–v314 · runtime versions skipped on chain (never deployed)

v315 block 6,414,634 Internal re-bind

v316–v319 · runtime versions skipped on chain (never deployed)

v320 block 6,523,566 Internal re-bind

v327–v333 · runtime versions skipped on chain (never deployed)

v334 block 6,811,690 Internal re-bind

v353–v360 · runtime versions skipped on chain (never deployed)

v361 block 7,063,679 Internal re-bind

v363–v364 · runtime versions skipped on chain (never deployed)

v365 block 7,135,419 Internal re-bind

v386–v390 · runtime versions skipped on chain (never deployed)

v391 block 7,782,857 Internal re-bind

v394–v400 · runtime versions skipped on chain (never deployed)

v401 block 8,036,576 Internal re-bind

v403–v410 · runtime versions skipped on chain (never deployed)

v411 block 8,283,784 Internal re-bind Current

Runtime Info

View Source

Pallet: SubtensorModule
Storage Kind: Map
First Version: v101
Current Version: v411

Back to SubtensorModule Storage