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Every order book payload — the REST snapshot and both orderbook_v3 channels — carries a version: a single string that increases as the book changes.
It answers one question: is this payload newer than the book I already hold?
version applies only to the orderbook channels — orderbook_v3 and orderbook_v3_event — and the REST snapshot that seeds them.

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The apply rule

Apply a payload only when its version is strictly greater than the one you hold:
Compare as strings. A plain string comparison gives the correct ordering — no need to parse it into a number or BigInt.

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Keep state per market, and seed it from REST

version is per market, so key your state by marketHash before you compare. Seed from the REST snapshot at startup, then apply only live publications that have a version greater than the seed or previous message.

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Gaps are normal

version is not a counter but it is increasing. Consecutive changes on a market jump by arbitrary amounts, not by 1.

Recovery & reliability

Recovery, ordering and deduplication across reconnects.

Get orderbook snapshot

The REST seed that carries the same version.

Fetching odds

Seeding and subscribing to the book and best odds.
Last modified on August 11, 2026