Bundlr’s bundling service collates transactions together into a bundle and submits to Arweave.

Uploading large numbers of files to Arweave can be technically challenging due to Arweave's limit of 1000 transactions per block. When demand spikes, that drives up storage fees, and spikes in network traffic can cause fees to increase by 10,000,000,000,000,000x, making permanent storage unaffordable for many users. To address these challenges, bundlers are used to collate transactions into a single bundle and submit them to Arweave.

These transactions are instantly retrievable and available to be queried via GraphQL, further detailed in the gateway section. It is not necessary to wait for uploads to be confirmed and seeded on Arweave before they appear in query results.

The implementation of bundlers and bundles has helped stabilize feeds on Arweave.


Our bundlers are highly scalable and have been tested at over 50,000 transactions per second (opens in a new tab).

Transaction Headers and Data Payload

Each upload to Arweave is composed of a transaction header and a data payload. Bundlers guarantee each transaction will be included in a block and ensures the data will be seeded to multiple reputable miners. This is further detailed in our documentation on transaction lifecycle.