System Constants

All hard-coded constants used across the XE network. These values are consistent between the Go node, web wallet, and explorer.

Proof of work

Constant

Value

Notes

DefaultDifficulty

0xfffff80000000000

~2M attempts, ~1s on single core

TestDifficulty

0x0000000000000002

Near-instant, for tests only

See Proof of Work for algorithm details.

Timing

Constant

Value

Used by

Block timestamp window

±1 hour

Block validation

Vote window

±5 minutes

Vote acceptance

Attestation skew

±10 minutes

Lease attestation validation

Quorum fallback delay

10 seconds

Conflict resolution timeout

Stale conflict sweep

15 seconds

Periodic conflict cleanup

Periodic sync

10 seconds

Frontier sync interval

Sync rate limit

5 seconds per peer

Per-peer sync throttle

Session timeout (wallet)

5 minutes

Auto-lock idle wallet

Poller interval (wallet)

5 seconds

Pending transaction check

Directory TTL

30 minutes

Account directory entry expiry

[!INFO] Timestamp windows The block timestamp window (±1 hour) is intentionally generous to accommodate clock drift between nodes. Votes use a tighter ±5 minute window because representatives are expected to have reasonably synchronized clocks.

Size limits

Protocol limits

Constant

Value

Description

Conflict hashes

10 max

Maximum competing block hashes per conflict

Pending votes per conflict

10 max

Maximum votes tracked per conflict

Attestations per block

20 max

Maximum timekeeper attestations per lease block

Gossip message size

256 KB

Maximum gossip pubsub message

Sync request size

1 MiB

Maximum sync request payload

Sync response size

10 MiB

Maximum sync response payload

Sync total blocks

10,000 per session

Maximum blocks transferred in one sync session

Frontiers per request

10,000

Maximum frontiers in a single request

State chain limits

Constant

Value

Description

State key

128 bytes max

Maximum key length for KV operations

State value

64 KB max

Maximum value size for KV operations

State block

256 KB max

Maximum serialized state chain block

Messaging limits

Constant

Value

Description

Message request

64 KB

Maximum chat message request

Message response

64 KB

Maximum chat message response

Lease economics

[!WARNING] Placeholder values The rates and economic constants below are dummy values for development. Final pricing is pending design review. See Cost Model.

Constant

Value

Description

Min duration

60 seconds

Shortest allowed lease

Max duration

31,536,000 seconds

Longest allowed lease (365 days)

vCPU rate

20 milli-XUSD / hour

Per-vCPU cost

Memory rate

10 milli-XUSD / GB / hour

Per-GB memory cost

Disk rate

1 milli-XUSD / GB / hour

Per-GB disk cost

Stake formula

Cost / 5 (min 1)

Provider stake requirement

XE reward

Same as cost

XE emitted to provider on settlement

[!EXAMPLE] Cost calculation A lease requesting 2 vCPUs, 4 GB memory, 50 GB disk for 24 hours (86400s):
perHourMilli = 2×20 + 4×10 + 50×1 = 130 milli-XUSD/hour
hours        = 24
costMilli    = 130 × 24 = 3120
cost         = ceil(3120 / 1000) = 4 XUSD
Stake        = 4 / 5 = 0 → min 1 = 1 XUSD
XE reward    = 4 XE

See Cost Model for the full pricing specification.

Performance certificates

Constant

Value

Description

BenchmarkIterations

375,000,000

Sequential SHA-256 hash chain (~60s on mid-range hardware)

MemoryTableSize

8,388,608

Memory table entries (256 MB at 32 bytes each)

MemoryReads

1,000,000

Sequential-dependency random reads from memory table

WorkloadVersion

Benchmark algorithm version (increment on changes)

CertificateValidity

7 days

How long a certificate is valid after issuance

See Performance Evaluation for benchmark and scoring details.

Consensus

Constant

Value

Description

Quorum threshold

67%

Voting weight required to confirm/reject

Connection manager low

100 peers

Minimum peer target

Connection manager high

400 peers

Maximum peer target

Connection grace period

1 minute

New connection protection window

Bootstrap retry

10 seconds

Retry interval for bootstrap dial

API

Constant

Value

Description

Rate limit (sustained)

100 req/sec

Per-IP sustained request rate

Rate limit (burst)

500 req

Per-IP burst allowance

Default API port

8080

HTTP API listen port

Default libp2p port

9000

libp2p TCP listen port

Default CORS origin

http://localhost:3000

Allowed CORS origin