Blocknative Gas API → GFP Field Mapping

BN shuts down June 19, 2026

Every field in Blocknative's /gasprices/blockprices response, mapped to its Gas Fee Predictor equivalent (or marked “not provided” with a workaround). Use this as the lookup reference while migrating. For step-by-step instructions and code samples, see the migration guide. For the high-level pitch, see the Blocknative alternative landing page.

Top-level response fields

Blocknative's /gasprices/blockprices endpoint returned these top-level fields. Equivalents from our /api/gas-predictions endpoint:

Blocknative field	GFP equivalent	Notes
`system`	`meta.source (implicit — always Ethereum mainnet)`	We are Ethereum-mainnet-only at this endpoint; L2 networks have their own /api/l2-gas endpoint.
`network`	`meta.source (RPC provider name, not "main"/"goerli")`	We report which RPC provider served the data (e.g., "rpc-publicnode") — different concept than Blocknative's network field, which was always "main" in production.
`unit`	`implicit (always gwei)`	All gas-price fields are in gwei. Not echoed in the response.
`maxPrice`	Not provided	Not provided. Blocknative used this as an upper-bound cap; we don't enforce one.
`currentBlockNumber`	Not provided	Not provided. If you need it, query an RPC directly: eth_blockNumber on any public node.
`msSinceLastBlock`	Not provided	Not provided. If you need block-timing data, query an RPC directly.
`blockPrices[]`	`current (single object) + predictions[] (hourly forecast)`	Blocknative returned an array per upcoming block. We collapse current to a single object and forecast hourly via predictions[].
`estimatedBaseFees[]`	`predictions[] (different shape — see below)`	Blocknative forecast per-block base fees. We forecast hourly with confidence + isLowFeeWindow flags.

`blockPrices[0]` inner fields

Most callers focused on the first element of blockPrices[] (the next block). Field-by-field:

Blocknative field	GFP equivalent	Notes
`blockPrices[0].blockNumber`	Not provided	Not provided. Same as currentBlockNumber above — query an RPC.
`blockPrices[0].estimatedTransactionCount`	Not provided	Not provided. Mempool-derived data not in scope.
`blockPrices[0].baseFeePerGas`	`current.low (approximate)`	Base fee + minimum priority fee ≈ what we report as current.low. Not an exact 1:1 because we always include some priority fee in low; pure base fee requires an RPC eth_feeHistory call.
`blockPrices[0].estimatedPrices[]`	`current.{low, average, high}`	Blocknative returned 5 confidence percentiles; we collapse to 3 tiers. Mapping below.

Confidence percentile → tier mapping

Blocknative returned 5 confidence percentiles (99 / 95 / 90 / 80 / 70). We collapse to 3 tiers (low / average / high). This is the most common transition point in real migrations.

Blocknative field	GFP equivalent	Notes
`estimatedPrices[c=99].price`	`current.high`	"Will-include" tier — fast inclusion expected within 1 block.
`estimatedPrices[c=95].price`	`current.high`	Approximately same as 99% in practice.
`estimatedPrices[c=90].price`	`current.average`	Typical wallet default tier.
`estimatedPrices[c=80].price`	`current.average`	Standard tier — most wallets use this as the default Send button price.
`estimatedPrices[c=70].price`	`current.low`	Slow inclusion — may take multiple blocks. Use for non-urgent transactions.
`estimatedPrices[c=*].maxPriorityFeePerGas`	Not provided	We don't break out priority fee from base fee. Set a reasonable static default (1-2 gwei) for EIP-1559 transactions, or query an RPC eth_feeHistory.
`estimatedPrices[c=*].maxFeePerGas`	`current.high (use as upper-bound)`	For EIP-1559 maxFeePerGas, current.high is a safe over-estimate. Add a 10-20% buffer if your wallet does padding.

Bonus: GFP fields without a Blocknative equivalent

Fields we expose that Blocknative didn't. Adopt these if your migration window is also a refactoring window:

Blocknative field	GFP equivalent	Notes
`(no equivalent — bonus)`	`nextBestTime`	Pattern-based "when is the next cheap window" forecast. Useful for scheduling non-urgent transactions.
`(no equivalent — bonus)`	`decision.recommendation`	Quick "wait" or "send_now" hint based on current vs predicted gas. Synthesizes nextBestTime + savings estimate.
`(no equivalent — bonus)`	`predictions[].isLowFeeWindow`	Boolean flag per hour marking predicted low-fee windows. Useful for cron-based dispatch.
`(no equivalent — bonus)`	`citation`	Stable copy-paste attribution string for AI agents and integrators. Drop directly into LLM answers.
`(no equivalent — bonus)`	`/api/l2-gas`	Live gas for Arbitrum, Optimism, Base, Polygon. Blocknative's gas API was L1-only. Includes full wallet-fee estimate with L1 data fee for OP Stack chains.

What we don't replace

Blocknative offered several products beyond the gas-price API. If you used these, you'll need a different provider for them:

Blocknative product	Typical use	Suggested alternative
Mempool data stream	Live pending-tx feed via WebSocket	Alchemy (eth_subscribe newPendingTransactions), Tenderly, Bloxroute
Transaction simulation	Pre-execution outcome prediction	Tenderly simulation API, Alchemy debug_traceCall
Transaction management	Submit, watch, re-submit (cancel/speed-up)	Alchemy, your own RPC node, Foundry forge scripts
Gas Network (decentralized oracle)	On-chain gas oracle for smart contracts	Chainlink fast gas oracle (where deployed), or read base-fee history from the chain directly
Per-block predictions	Next 1-5 block base-fee forecast	Compute from RPC eth_feeHistory directly, or use our hourly predictions[] for longer-horizon scheduling
WebSocket streaming	Push updates without polling	Poll our endpoints every 30-60s (edge-cached, no rate-limit cost). No WebSocket support on our side.

Side-by-side response shape

For visual reference — what your code is parsing before and after migration:

Blocknative `/gasprices/blockprices`

{
  "system": "ethereum",
  "network": "main",
  "unit": "gwei",
  "maxPrice": 50,
  "currentBlockNumber": 18000000,
  "msSinceLastBlock": 5000,
  "blockPrices": [
    {
      "blockNumber": 18000001,
      "estimatedTransactionCount": 200,
      "baseFeePerGas": 30.5,
      "estimatedPrices": [
        { "confidence": 99, "price": 35.5, "maxPriorityFeePerGas": 2,   "maxFeePerGas": 67 },
        { "confidence": 95, "price": 33.2, "maxPriorityFeePerGas": 1.5, "maxFeePerGas": 65 },
        { "confidence": 90, "price": 32,   "maxPriorityFeePerGas": 1,   "maxFeePerGas": 64 },
        { "confidence": 80, "price": 30.5, "maxPriorityFeePerGas": 0.5, "maxFeePerGas": 62 },
        { "confidence": 70, "price": 30,   "maxPriorityFeePerGas": 0.1, "maxFeePerGas": 61 }
      ]
    }
  ],
  "estimatedBaseFees": [ /* per-block forecast */ ]
}

Gas Fee Predictor `/api/gas-predictions`

{
  "current": { "low": 0.39, "average": 0.50, "high": 0.62, "source": "rpc-publicnode" },
  "historical": [ /* recent samples */ ],
  "predictions": [
    { "timestamp": "...", "low": 0.30, "average": 0.40, "high": 0.55, "isLowFeeWindow": true, "confidence": 0.85 }
    /* … 24 hourly points */
  ],
  "nextBestTime": { "timestamp": "...", "gasPrices": {...}, "confidence": 0.82 },
  "decision": { "recommendation": "wait", "expectedSavingsPct": 35, ... },
  "timeframe": "24h",
  "lastUpdated": "...",
  "meta": { ... },
  "citation": "Gas data from Gas Fee Predictor, gasfeepredictor.com, updated ...",
  "tier": "free"
}

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Step-by-step walkthrough with before/after code in curl, JavaScript, Python, and Go.

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