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Networking · head to head

Eclipse Mosquitto vs Semgrep

Eclipse Mosquitto logo

Eclipse Mosquitto

Networking

Small, EPL-licensed MQTT broker that runs on hardware other brokers cannot

From
Free
Rated
-
Full reviewWebsite
Semgrep logo

Semgrep

Cybersecurity

Open-source static analysis tool for finding security bugs and enforcing code standards.

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Eclipse Mosquitto there is no clustering: Mosquitto is a single process, so high availability means building your own failover and accepting session loss on switchover.; Semgrep free tier caps out at 10 contributors and 10 repositories.
  • They diverge on capability: Eclipse Mosquitto covers MQTT 5.0 support, Semgrep covers Static code scanning.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Eclipse Mosquitto and Semgrep actually diverge.

Attributes where Eclipse Mosquitto and Semgrep differ
AttributeEclipse MosquittoSemgrep
Pricing modelOpen source, no licence feefreemium
PlatformsLinux, Windows, macOS, Dockerweb, api, linux, mac, windows
CategoryNetworkingCybersecurity

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Eclipse Mosquitto

  • MQTT 5.0 support
  • Very small footprint
  • Bridging
  • WebSockets listener
  • Command line clients
  • Dynamic security plugin

Only in Semgrep

  • Static code scanning
  • Supply chain scanning
  • Secrets detection
  • Cross-file analysis
  • AI-powered triage and remediation
  • CI/CD integration

What people use each for

The jobs each tool is most often brought in to do.

Eclipse Mosquitto

  • A home or building automation stack where the broker must run on the same small computer as everything elsenot Semgrep
  • An industrial gateway that buffers local telemetry and bridges selected topics to a cloud brokernot Semgrep
  • Local development and testing of MQTT clients without provisioning a cloud IoT servicenot Semgrep
  • An air-gapped deployment where a broker with no licence server and no phone-home behaviour is a requirementnot Semgrep

Semgrep

  • Scanning code for security vulnerabilities in CI/CDnot Eclipse Mosquitto
  • Detecting vulnerable open-source dependenciesnot Eclipse Mosquitto
  • Finding hardcoded secrets before code shipsnot Eclipse Mosquitto
  • Enforcing custom code standards with rule setsnot Eclipse Mosquitto
  • Prioritizing findings with AI-assisted triagenot Eclipse Mosquitto

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Eclipse Mosquitto

  • There is no clustering: Mosquitto is a single process, so high availability means building your own failover and accepting session loss on switchover.
  • Persistence is a local file rather than a replicated store, so a disk failure or an unclean shutdown can lose retained messages and queued QoS traffic.
  • Practical capacity is a few thousand concurrent clients on typical hardware, so a growing device fleet eventually forces a migration to a clustered broker.
  • The Eclipse Public Licence is weak copyleft rather than permissive, which some legal teams treat as a blocker when embedding the broker in a shipped commercial product.
  • There is no commercial support to buy from the project, so production incidents rely on community mailing lists or on paying a third party who happens to know the codebase.

Semgrep

  • Free tier caps out at 10 contributors and 10 repositories.
  • Secrets scanning is priced as a separate module ($15/contributor) from Code and Supply Chain.
  • Self-managed repositories and custom CI/CD require the Enterprise tier.
  • AI credits are limited per tier and additional usage requires upgrading.

Pricing, plan by plan

Eclipse Mosquitto

Free
  • Eclipse MosquittoFree
    • Eclipse Public License 2.0 with Eclipse Distribution Licence
    • MQTT 5.0, 3.1.1 and 3.1
    • No client or message limits beyond your hardware

Semgrep

Free
  • FreeFree
    • Up to 10 contributors
    • Code and Supply Chain scanning
    • 60 AI credits total
  • Teams$30/month
    • Code, Supply Chain, or Secrets scanning per contributor
    • Pro rules
    • AI-powered triage and remediation
  • Enterprise$undefined/month
    • On-prem support
    • Custom CI/CD
    • 50 AI credits per developer/month

Which should you pick?

Choose Eclipse Mosquitto if

  • You need mqtt 5.0 support.
  • You want to start without paying.
  • You work on Linux, Windows, macOS, Docker.
  • You also want very small footprint.
Eclipse Mosquitto review

Choose Semgrep if

  • You need static code scanning.
  • You want to start without paying.
  • You work on web, api, linux, mac, windows.
  • You also want supply chain scanning.
Semgrep review

Questions people ask

Is Eclipse Mosquitto or Semgrep better?
Neither clearly leads. Eclipse Mosquitto starts at Free and Semgrep at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Eclipse Mosquitto or Semgrep?
Eclipse Mosquitto starts at Free and Semgrep at Free.
Does Eclipse Mosquitto or Semgrep run on more platforms?
Eclipse Mosquitto runs on Linux, Windows, macOS, Docker. Semgrep runs on web, api, linux, mac, windows.
Can I use Eclipse Mosquitto for free?
Both have a free tier, so you can try either at no cost before committing.
What is Eclipse Mosquitto best used for?
Eclipse Mosquitto is most often used for a home or building automation stack where the broker must run on the same small computer as everything else, an industrial gateway that buffers local telemetry and bridges selected topics to a cloud broker, local development and testing of mqtt clients without provisioning a cloud iot service, an air-gapped deployment where a broker with no licence server and no phone-home behaviour is a requirement. Of those, a home or building automation stack where the broker must run on the same small computer as everything else and an industrial gateway that buffers local telemetry and bridges selected topics to a cloud broker are not what Semgrep is typically brought in for.
What can Eclipse Mosquitto do that Semgrep cannot?
Eclipse Mosquitto covers MQTT 5.0 support, Very small footprint, Bridging, WebSockets listener. Semgrep covers Static code scanning, Supply chain scanning, Secrets detection, Cross-file analysis.

Answered from the vendors’ own pages

Eclipse Mosquitto: Can Mosquitto be clustered?

No. It is a single process. High availability requires an external failover arrangement you build yourself.

Semgrep: What does Semgrep cost?

The Free edition covers up to 10 contributors; Teams starts at $30/contributor/month for Code scanning (Supply Chain also $30, Secrets $15); Enterprise is custom-priced.

Source
Eclipse Mosquitto: What licence is it?

Eclipse Public License 2.0 alongside the Eclipse Distribution License, a weak copyleft rather than a permissive licence.

Semgrep: Is there a free plan, and what are its limits?

Yes, the Free edition supports up to 10 contributors and 10 repositories with Code and Supply Chain scanning plus 60 AI credits total.

Source
Eclipse Mosquitto: How many clients can it handle?

A few thousand concurrent connections on ordinary hardware; beyond that, use a clustered broker.

Semgrep: How is usage metered?

Pricing is per contributor, defined as someone who made at least one commit to a scanned private repository in the past 90 days.

Source
Eclipse Mosquitto: Does it support MQTT 5?

Yes, along with 3.1.1 and 3.1.

Semgrep: Is there special pricing for startups?

Yes, Semgrep offers special startup pricing upon request for early-stage companies.

Source
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