Quickstart

Endpoints

Choose the endpoint closest to your location:

• Frankfurt: frankfurt.nextblock.io

• Amsterdam: amsterdam.nextblock.io

• London: london.nextblock.io

• Singapore: singapore.nextblock.io

• Tokyo: tokyo.nextblock.io

• New York: ny.nextblock.io

• Salt Lake City: slc.nextblock.io

Tip Wallets

Your TX must include a plain SOL Transfer IX to one of our tip wallets.

Higher tips = higher priority. Use the tip floor API to determine optimal tip amounts based on current network conditions.

• NextbLoCkVtMGcV47JzewQdvBpLqT9TxQFozQkN98pE

• NexTbLoCkWykbLuB1NkjXgFWkX9oAtcoagQegygXXA2

• NeXTBLoCKs9F1y5PJS9CKrFNNLU1keHW71rfh7KgA1X

• NexTBLockJYZ7QD7p2byrUa6df8ndV2WSd8GkbWqfbb

• neXtBLock1LeC67jYd1QdAa32kbVeubsfPNTJC1V5At

• nEXTBLockYgngeRmRrjDV31mGSekVPqZoMGhQEZtPVG

• NEXTbLoCkB51HpLBLojQfpyVAMorm3zzKg7w9NFdqid

• nextBLoCkPMgmG8ZgJtABeScP35qLa2AMCNKntAP7Xc

gRPC

For those wishing to use gRPC, we have created sample docs. at our GitHub

Anti-MEV

To enable Anti-MEV, set frontRunningProtection: true in your request as shown:

curl -X 'POST' 'http://frankfurt.nextblock.io/api/v2/submit' -header "Authorization: $AUTH_HEADER" -d '{ "transaction": {"content": "FtQ+KrJeNuiismV1Ke...DBABRQ=="}, "frontRunningProtection": true, }'

Priority Fees & Retries

If anti-MEV is enabled, priority fee does not matter, only the NextBlock Tip matters.

If anti-MEV is disabled, ensure you use a good priority fee to maintain a competitive position amongst others during block production. Use the tip floor API to determine appropriate priority fees based on current network conditions.

When sending without frontRunningProtection: true, your transaction is sent via all channels: our internal validator network, Jito Bundles, and as a normal transaction to upcoming leaders.

NextBlock's intelligent retry system actively tracks on-chain activity levels and adjusts dynamically to send transactions more aggressively during congestion and less aggressively during downtime. Simply send us the transaction once - we take care of the rest, no retries needed on your end.