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VegaLoad vs Locust

Checked on 13 October 2026, against Locust 2.46.

Locust is an open source tool where you write your tests as plain Python. It has a live web UI and a distributed mode with workers.

Choose Locust when your team lives in Python and wants to write custom user behavior with any Python library. Choose VegaLoad when you want many protocols in one binary, and a first run with no code.

At a glance​

VegaLoadLocust
Language and runtimeGo. One static binary. Python scenarios need a local python3Python. Each simulated user runs in its own greenlet (gevent)
How a test is writtenOne command in direct mode, or a scenario file in JavaScript, TypeScript or PythonA Python file called a locustfile
Protocols14 built in: HTTP/1.1, HTTP/2, gRPC, WebSocket, MQTT, Kafka, PostgreSQL, MySQL, Redis, RabbitMQ, FTP, SFTP, TCP, UDPMainly HTTP. Other protocols by writing a custom client
Pass or fail limits-threshold, checks and -baseline. A breach exits 3Exit code 1 if any request failed. To fail on slow responses, set the exit code from a short snippet in the locustfile
ReportsSelf-contained HTML, JSON and JUnit XMLA live web UI. --html writes an HTML report to a file
Distributed loadNot built in. A Helm chart runs one test as a Kubernetes Job. Distributed load through Harness Resilience Testing is plannedOne master and many workers (--master, --worker). One process uses one core, so you run one worker per core
AI agents and MCPMCP server in the same binary with 9 tools. vegaload init sets up Cursor and Claude Code. Host allow-list and audit logWe did not find an official MCP server. A community-built one exists
LicenseApache 2.0MIT
Import and recordingOpenAPI (vegaload new -from-openapi) and HAR (vegaload import har). JMeter and k6 import are plannedNot covered here

The same test in both tools​

Ten users, a health endpoint, a limit on the 95th percentile.

VegaLoad

vegaload run -target https://staging.example.com/health -protocol http1 \
  -vus 10 -duration 30s -threshold 'p95 < 500ms' \
  -allow-target staging.example.com

Locust

# locustfile.py
from locust import HttpUser, task

class Health(HttpUser):
    @task
    def health(self):
        self.client.get("/health")
locust -f locustfile.py --headless -u 10 -r 10 -t 30s \
  --host https://staging.example.com --html report.html

This runs and writes a report. To also fail the run when the 95th percentile is too high, Locust's docs show a short snippet that sets the exit code. We ran this test for a few seconds against a local server with Locust 2.46.7. It ran and wrote an HTML report. We did not run the failing-limit snippet.

Choose Locust when​

  • Your team writes Python and wants full control of user behavior in code.
  • You want a live web UI where you can change the load during a run.
  • You want to use any Python library inside the test.
  • You want to add a custom client for a protocol we do not cover.

Choose VegaLoad when​

  • You want a first run with no code.
  • You test databases, queues, Redis, FTP or SFTP, and you want them built in.
  • You want one static binary with no Python environment to manage.
  • You want your AI agent to run tests, with a host allow-list and an audit log.
  • You want a pass or fail limit with one flag.

Moving from Locust​

There is no import. A Locust file is Python code, and VegaLoad scenarios have their own API. See Moving to VegaLoad. VegaLoad can also run a Python scenario, but it shells out to a local python3, and it is not the Locust API.

Sources​