What is VRL, and why does the transform need a snippet of it?

VRL (Vector Remap Language) is Vector's built-in expression language for transforming events, used inside a remap transform's source field. A single VRL line like .new_field = "value" adds or modifies fields on every event passing through, and Vector runs it natively (compiled, not interpreted line-by-line), which is why remap is Vector's primary transform type.

How does Vector wire sources, transforms, and sinks together?

Every transform and sink declares an inputs array listing the component IDs that feed it. This generator sets the transform's inputs to the source's ID and the sink's inputs to the transform's ID automatically, so the pipeline is connected correctly without you having to keep the IDs in sync by hand.

What's the difference between the file and http_server sources?

file tails one or more local log files on disk, matching the include glob pattern you provide. http_server instead listens on a network address and accepts incoming HTTP requests as events, useful for receiving logs pushed from another service rather than reading them from a file.

Why would I pick Vector over Fluentd or Fluent Bit?

Vector is written in Rust and built around a single high-performance binary with VRL for transforms, which many teams choose for its throughput and memory characteristics compared to Fluentd, and for having a more expressive transform language than Fluent Bit's Lua-scripting-or-nothing approach to filtering.

Vector Config Generator - Build vector.toml Visually

Overview

Introduction

Vector's vector.toml format is straightforward TOML, but a pipeline is only correct if every transform and sink's inputs array points at the right upstream component ID, and a typo there produces a component that silently receives nothing.

This tool builds a vector.toml from a form: define a source, write a VRL snippet for the remap transform, choose a sink, and the inputs arrays are wired together automatically from the IDs you chose.

What Is Vector Config Generator?

A visual builder for vector.toml pipelines covering one source ([sources.<id>], file or http_server), one remap transform ([transforms.<id>], type = "remap" driven by a VRL source snippet), and one sink ([sinks.<id>], elasticsearch, loki, or console).

It follows Vector's actual TOML configuration schema, including the triple-quoted multi-line string syntax VRL snippets use inside a remap transform's source field.

How Vector Config Generator Works

You choose an id for the source, transform, and sink (validated as lowercase identifiers and required to be distinct); the transform's inputs is set to ["<source id>"] and the sink's inputs is set to ["<transform id>"] automatically, so the pipeline always connects correctly.

The VRL snippet you write is inserted verbatim between Vector's ''' triple-quote delimiters as the remap transform's source field. The sink's destination-specific fields (endpoint/bulk.index for elasticsearch, endpoint/labels for loki, or target/encoding for console) are only included for the sink type you selected.

When To Use Vector Config Generator

Use it when standing up a new Vector pipeline and you want a correctly wired vector.toml without hand-tracking which component ID feeds which.

It's also useful for quickly sketching a VRL remap snippet's placement inside a real transform block before testing it further with the Vector VRL Playground.

Features

Advantages

Automatically wires inputs arrays between source, transform, and sink, eliminating the most common Vector pipeline mistake, a component whose inputs points at a nonexistent or misspelled ID.
Emits VRL snippets using Vector's real triple-quoted multi-line string syntax, ready to paste into an actual vector.toml.
Covers three genuinely different sink shapes (elasticsearch, loki, console) with each one's real field names, rather than one generic output block.

Limitations

Only models one source, one transform, and one sink; real Vector pipelines often chain multiple transforms or fan out to several sinks, which this generator doesn't build.
Doesn't validate the VRL snippet's syntax, only that a non-empty snippet was provided, actual VRL syntax errors are only caught when Vector itself parses the config.
Doesn't generate authentication fields (API keys, AWS auth) for the elasticsearch or loki sinks, which most hosted destinations require in production.

Examples

Tailing a log file, tagging it, and shipping to Elasticsearch

Input

source: file, include /var/log/app.log; transform: remap, .environment = "production"; sink: elasticsearch, endpoint http://localhost:9200, index app-logs

Output

[sources.in]
type = "file"
include = ["/var/log/app.log"]

[transforms.parse]
type = "remap"
inputs = ["in"]
source = '''
.environment = "production"
'''

[sinks.out]
inputs = ["parse"]
type = "elasticsearch"
endpoint = "http://localhost:9200"
bulk.index = "app-logs"

The transform's inputs automatically references the source id (in), and the sink's inputs automatically references the transform id (parse).

Best Practices & Notes

Best Practices

Give sources, transforms, and sinks short, descriptive ids (like app_logs, add_env, es_out) rather than generic ones, since Vector's own observability metrics are labeled by component id.
Keep VRL snippets focused on one concern per transform, chaining several small, readable remap transforms tends to be easier to debug than one large VRL block.
Add authentication fields for elasticsearch or loki sinks manually after generating, since hosted deployments almost always require them.

Developer Notes

The generator emits plain TOML text without a TOML library, since Vector's config shape here is simple enough for direct string templating; VRL snippets are inserted between literal ''' delimiters matching Vector's own multi-line string syntax. Component ids are validated against /^[a-z][a-z0-9_]*$/ and checked for pairwise uniqueness before generating, so the emitted inputs arrays are always internally consistent.

Vector Config Generator Use Cases

Standing up a new Vector pipeline to tail an application log and ship it to Elasticsearch or Loki
Prototyping a VRL remap snippet's placement inside a real transform block before deeper testing
Producing a console-sink pipeline to preview transformed events locally before wiring in a real destination

Common Mistakes

Reusing the same id for two different components, Vector requires every source, transform, and sink id to be unique across the whole config.
Writing a VRL snippet that references a field that doesn't exist on the incoming event, which raises a runtime error in Vector unless handled with VRL's error-handling syntax.
Forgetting that hosted Elasticsearch or Loki endpoints usually need authentication fields this generator doesn't include.

Tips

Use the console sink first while developing a new VRL transform, it's the fastest way to see exactly what your remap logic produces before pointing the pipeline at a real destination.
Use the Fluent Bit Config Generator instead if you need an agent with a smaller footprint for a resource-constrained edge device.

Vector Config Generator