Push S-Value pattern: Supra updates an on-chain feed; readers call getSvalue(pairId) and must reject empty, zero, or stale quotes.
Supra push oracle → getSvalue(pairId) → consumer
Consumers may wrap the feed behind a local interface; that is optional. Do not assume a project-specific adapter name.
Quick Reference
| Piece | Role |
|---|---|
| Push oracle | Immutable ISupraSValueFeed address for the network |
| Pair ID | Numeric Supra pair id (not an EVM aggregator address) |
| Read | getSvalue(pairId) → price, decimals, time |
| Time | Often milliseconds on Hedera — convert when time > 1e10 |
| Quote asset | Hedera feeds are often USDT, not USD |
| Freshness | Compare unix seconds to a max staleness |
Hedera chain IDs: testnet 296, mainnet 295.
See references/hedera-feeds.md for where to source push-oracle addresses and pair IDs. See references/examples.md for read sketches.
Critical: Millisecond Timestamps
Supra time on Hedera is frequently milliseconds. Treat values > 10_000_000_000 as ms and convert before staleness checks:
uint256 updatedAt = pf.time > 10_000_000_000 ? pf.time / 1_000 : pf.time;
if (block.timestamp - updatedAt > maxStaleness) revert StalePrice(updatedAt, maxStaleness);
Comparing a millisecond timestamp to block.timestamp (seconds) will look “in the future” or skip staleness incorrectly.
Critical: USDT Pairs On Hedera
Current Hedera Supra feeds often quote USDT, not USD. Pair keys / symbols must match the actual quote (HBAR/USDT, BTC/USDT). Do not label a USDT feed as USD.
Completeness And Invalid Prices
Revert when:
| Condition | Why |
|---|---|
pf.time == 0 |
No successful update |
pf.price == 0 |
Invalid price |
| Stale after converting to seconds | Older than maxStaleness |
| Unknown pair ID | Do not return zero |
Normalize pf.price with pf.decimals to the consumer scale (often 18).
Checklist
When implementing or reviewing Supra reads on Hedera:
- Push-oracle address and pair IDs taken from Supra Hedera docs (not Ethereum)
- Timestamps converted to unix seconds when they look like milliseconds
- Pair symbols match the real quote asset (often USDT)
- Zero / missing updates revert
- Staleness bound is enforced in seconds
- Decimals normalized to the consumer scale
References
- references/examples.md —
getSvalueand timestamp sketches - references/hedera-feeds.md — where to source push-oracle addresses and pair IDs
- Supra push oracle networks
- Supra data feeds index