Bento is an MIT-licensed, config-driven stream processor — the OSI-open fork of Benthos before it became source-available Redpanda Connect.
Yes, Bento is open source under the MIT license.
Bento is free to use.
Yes, Bento can be self-hosted (the source is available under the MIT license).
Bento is a stream-processing framework maintained by WarpStream Labs — "fancy stream processing made operationally mundane." It provides declarative, config-driven pipelines that connect data sources to sinks with transformations and enrichments in between, guaranteeing at-least-once delivery through in-process transactions. It supports a broad set of brokers and cloud services including Kafka, AWS, Azure, and GCP. Written in Go.
Its reason to exist is licensing: Bento is forked from Benthos before that project was relicensed to the source-available Redpanda Connect, so it is the OSI-open continuation for teams that need a permissively-licensed stream processor rather than a source-available one.