History & Backfill: How Far Back Do You Need to Index?

When you move an endpoint onto Data Feeds, one early decision shapes your setup cost: how far back does the sink need to index? Get it right and you avoid both wasted backfill and, more importantly, silently wrong results. The answer depends on whether the endpoint returns current state or an event list.

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The rule of thumb

Current-state answers need full history. Event-list answers need only as much history as you want to show.

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Current state → needs full history

Balances, holders, approvals, native balances, total supply, token metadata, these describe what is true right now, and “right now” is the cumulative result of every past event. You can’t know a wallet’s current balance without its most recent transfer, and that transfer could have happened at any point since the token launched. Data Feeds make this efficient, each transfer carries the absolute balance after it (*PostBalance), so a recipe just keeps the latest observation per holder rather than replaying every delta. But “latest” still means you must have seen each holder’s most recent transfer. Start indexing too late and you simply miss every holder whose last activity predates your start, an incomplete, quietly wrong result. So for correctness, backfill from the beginning of the relevant history:

• By a single token (e.g. all holders of token X) → from that token’s first block (its deployment). You don’t need chain genesis, just everything since the token existed. Much cheaper.
• By a wallet across all tokens (e.g. a wallet’s full balance set) → effectively full history, because the wallet may still hold something it last touched years ago.

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Event list → your choice

Swaps, transfers, raw logs, price history, NFT trades, a wallet’s activity feed, these are append-only streams of past events. Each event is independent, so there’s no cumulative state to reconstruct. Backfill is purely a product decision: how much history do you want to display or analyze?

• Only need new activity from now on? Run realtime with no backfill.
• Want the last 90 days, or since a token launched, or everything? Backfill to that point.
• Either way the data is correct, you’re just choosing the window.

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Quick reference

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How to set it

Recipes run in three modes, historical (backfill a window), realtime (live tail), or hybrid (backfill then hand off to live). For current-state answers, use historical or hybrid with the start block set to the beginning of the relevant history (MORALIS_HISTORICAL_FROM_BLOCK); for event lists, pick whatever window your product needs, or realtime-only. Each migration guide states the specific answer for its endpoint up front, so you can size the backfill before you start.