Knapsack Pro

Semaphore CI vs Buildkite comparison of Continuous Integration servers
What are the differences between Semaphore CI and Buildkite?

Semaphore CI

https://semaphoreci.com

Buildkite

https://buildkite.com
Unique feature

Autoscaling made easy / Great CLI

Runs on own infrastructure, API

Type of product

SaaS

SaaS

Offers a free plan

Yes

1,300 service minutes every month. Plans to release a free tier for open source projects.

Yes

Free for open source projects and selected organizations

Predictable pricing

Yes

Semaphore doesn't have traditional pricing tiers, instead it lists the types of machines you can use and their pricing per second of service. They plan to release an annual plan at some point.

Yes

Clearly defined monthly and annual plans

Support / SLA

N/A

Not clear if they offer any real SLA on support.

Yes

Depending on the plan, ranging from community support, all the way to an assigned Technical Manager, SLAs and live chat support.

Paralellism
Every CI servers tends to address this differently (parallel, distributed, build matrix). Some of it is just marketing, and some is just nuance. For this table, parallel means that tasks can be run concurrently on the same machine, distributed means that tasks can be scaled horizontally, on multiple machines
How to split tests in parallel in the optimal way with Knapsack Pro

Yes

Allows defining a custom build matrix such that your build can be parallelized accross several different environments.

Yes

Run an unlimited number of concurrent agents, and an unlimited number of concurrent jobs. You can run your tests in isolated Docker container per agent.

Distributed builds
distributed means that tasks can be scaled horizontally, on multiple machines
How to split tests in parallel in the optimal way with Knapsack Pro

N/A

Yes

Run an unlimited number of concurrent agents, and an unlimited number of concurrent jobs

Containers support / Build environment

Yes

Allows running builds inside docker containers

Yes

Since the agents run on your own infra, you're free to do whatever

Analytics / Status overview
Analytics and overview referrs to the ability to, at a glance, see what's breaking (be it a certain task, or the build for a specific project)

Yes

Yes

The Buildkite UI features great vizualisations that feature build times, error rates, and more.

Management support
How easy is it to manage users / projects / assign roles and permissions and so on

Yes

Yes

Self-hosted option

No

No

Hosted plans / SaaS

Yes

Yes

Build pipelines
A continuous delivery pipeline is a description of the process that the software goes through from a new code commit, through testing and other statical analysis steps all the way to the end-users of the product.

Yes

Allows defining complex build workflows with ease

Yes

Pipelines are defined using an Yaml config file and allow for great flexibility in defining what each step of the process does.

Reports
Reports are about the abilty to see specific reports (like code coverage or custom ones), but not necesarily tied in into a larger dashboard.

N/A

Yes

Ecosystem
Besides the official documentation and software, is there a large community using this product? Are there any community-driven tools / plugins that you can use?

N/A

Yes

Integrations for GitHub, GitLab, BitBucket as well as SSO support (Google Suite, SAML, GraphQL API). Growing number of community plugins: https://buildkite.com/plugins

Specific language support: Ruby
Some CI servers have built-in support for parsing RSpec or Istanbul output for example and we mention those. Some others make it even easier by detecting Gemfiles or package.json and automate parts of the process for the developer.

Yes

Provides rich documentation on integrating Semaphore CI in Ruby projects. Also provides sudo access if you need to install system dependencies or C extensions.

Yes

You can find useful plugins like https://github.com/sj26/rspec-buildkite https://github.com/ticky/simplecov-buildkite etc

Specific language support: JavaScript

Yes

Provides rich documentation on integrating Semaphore CI in Javascript projects

No

Integrations
1st party support for common tools (like Slack notifications, various VCS platforms, etc)

Yes

Integration with GitHub and Slack. They allow building iOS projects via their macOS Mojave VM image.

Yes

Integrations for GitHub, GitLab, BitBucket as well as SSO support (Google Suite, SAML, GraphQL API)

API
Custom integreation is available, via an API or otherwise, it's mentioned separately as it allows further customization than any of the Ecosystem/Integration options

No

Yes

Great GraphQL API, allows building your own dashboard with ease

Auditing

Yes

Yes

Additional notes

List of features is based on Semaphore 2.0

Running Rails tests in parallel on Semaphore CI 2.0 with dynamic test files split

Buildkite parallel agents and how to use them for CI parallelisation

Semaphore CI parallelism integration

Buildkite parallelism integration

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