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

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¶

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

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`	3	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