Bitcoin blockspace · API

Blockspace, delivered.

Reserve room in a future Bitcoin block. Your transaction stays private until it's mined, pays no fee, and is proven on-chain.

Upcoming blocksTip 921,403
  1. 921,404
  2. 921,405
  3. 921,406
  4. 921,407
  5. 921,408
  6. 921,409
  7. 921,410
  8. 921,411Reserved · 4,000 WU
  9. 921,412

Demo · mock data

Private

Never broadcast. Your transaction goes straight into the block template and becomes public only when the block is mined.

Reserved

Space is contracted in advance, not bid for in the fee market. Delivered transactions pay no fee.

Your keys

You sign. CORSA never holds a key.

Verifiable

Delivery is proven on-chain and checkable on any block explorer.

The difference

Compete for space vs. contract for it

Public mempool
  • —Fee auction against every other sender
  • —Visible to everyone before confirmation
  • —No guarantee of which block, or when
CORSA
  • +Reserved weight units, contracted in advance
  • +Private until the block is mined
  • +A defined delivery window by block height
  • +On-chain proof of delivery
Lifecycle

How a transaction reaches a block

  1. 01

    Sign

    In your wallet

  2. 02

    Submit

    Against a contract

  3. 03

    Validate

    Accepted or rejected with a reason

  4. 04

    Stage

    Held privately until the window

  5. 05

    Mine

    In the block template

  6. 06

    Prove

    txid + block + coinbase

Everything that can be refused is refused at step 3, never at mining time.

Use cases

Built for transactions that need a window

Data anchoring & timestamping

Commit hashes to Bitcoin in a known block window.

Inscriptions & data outputs

Publish data without exposure to fee spikes.

Treasury & settlement

Transactions that need a guaranteed delivery window.

Consolidations

Combine outputs on your schedule, at a contracted size.

Forwards & futuresComing soon

Block capacity as a forward contract.

Lock in future blockspace at a known price, with physical delivery: a real transaction in a real block. Learn more

Reserve your first block.

Request access