Streamlit UI¶

A web interface for selecting schemas, editing them, previewing generated data, and producing directly to Kafka.

Quick start¶

pip install "avro-datagen[ui]"
avro-datagen ui

Opens at http://localhost:8501. No clone needed -- the app, example schema, and theme are bundled in the pip package.

Options¶

avro-datagen ui                              # default port 8501
avro-datagen ui --port 3000                  # custom port
avro-datagen ui --schema-dir ./my-schemas    # use your own schemas
avro-datagen ui --kafka                      # enable Kafka producer section

Flag	Default	Description
`--port`	`8501`	Port to run the UI on
`--schema-dir`	bundled schemas	Directory containing `.avsc` files
`--kafka`	off	Enable Kafka sidebar and producer section

With Kafka¶

By default the UI has no Kafka dependency. To enable the Kafka connection sidebar and produce section:

pip install "avro-datagen[app]"    # includes confluent-kafka
avro-datagen ui --kafka

Schema resolution¶

The UI looks for schemas in this order:

--schema-dir flag (if provided)
SCHEMA_DIR environment variable (if set)
./schemas/ in the current directory (if it exists)
Bundled example schemas from the package

Features¶

Schema tabs¶

Tab	Description
Local schemas	Pick from `.avsc` files. Collapsible JSON view + sample record
Upload	Drop any `.avsc` or `.json` file. Collapsible JSON view + sample record
Editor	Full JSON editor. Live sample record updates as you type. Save to file or download

Generate¶

Set record count and seed
Records generated in one batch, displayed as a table
Metrics: count, generation rate (rec/s), elapsed time
Expandable "How fields are resolved" section explains the resolution path for each field

Kafka Produce¶

Configure connection, auth, and tuning via the sidebar
Real-time progress with Produce / Stop controls
Live metrics: sent, errors, elapsed

Environment variables¶

All sidebar fields can be pre-filled via environment variables or a .env file:

Field	Environment variable	Default
Bootstrap servers	`KAFKA_BOOTSTRAP_SERVERS`	`localhost:29092`
Topic	`KAFKA_TOPIC`	`transactions`
Security protocol	`KAFKA_SECURITY_PROTOCOL`	(none)
SASL mechanism	`KAFKA_SASL_MECHANISM`	(none)
Username	`KAFKA_SASL_USERNAME`	(none)
Password	`KAFKA_SASL_PASSWORD`	(none)
Linger (ms)	`KAFKA_LINGER_MS`	`5`
Batch size	`KAFKA_BATCH_SIZE`	`16384`
Compression	`KAFKA_COMPRESSION_TYPE`	`none`
Schema directory	`SCHEMA_DIR`	(bundled)

Valid values for KAFKA_COMPRESSION_TYPE: none, gzip, snappy, lz4, zstd. An unknown value falls back to none.

Schema editor¶

The editor tab lets you modify the full schema JSON. When the JSON is valid:

A sample record is rendered below
Save to file writes back to the original .avsc (or schemas/ for new schemas)
Download exports as a .avsc file
Reset reverts to the originally loaded schema

The edited schema is used by both Generate and Kafka Produce sections.