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AutoSpotting is the leading open source spot market automation tool, optimized towards quick/easy/frictionless adoption of the EC2 spot market at any scale.

It is usually set up to monitor existing long-running AutoScaling groups with minimal configuration changes(often just tagging them, but even that can be avoided by using their existing tags), yielding the usual 70%-90% Spot cost savings but in a better integrated, more cost effective and easier to adopt way than the alternative tools and solutions.

How does it work?

Once installed and enabled by tagging to run against existing on-demand AutoScaling groups, AutoSpotting gradually replaces their on-demand instances with cheaper spot instances that are at least as large and identically configured to the group's members, without changing the group launch configuration in any way. You can also keep running a configurable number of on-demand instances given as percentage or absolute number and it automatically fails over to on-demand in case of spot instance terminations.

Going forward, as well as on any new ASGs that match the expected tags, any new on-demand instances above the amount configured to be kept running will be immediately replaced with spot clones within seconds of being launched.

If this fails temporarily due to insufficient spot capacity, AutoSpotting will continuously attempt to replace them every few minutes until successful after spot capacity becomes available again. When launching Spot instances, the compatible instance types are attempted in increasing order of their price, until one is successfully launched, lazily achieving diversification in case of temporary unavailability of certain instance types.

This process can partly be seen in action below, you can click to expand the animation:


Additionally, it implements an advanced logic that is aware of spot and on demand prices, including for different spot products and configurable discounts for reserved instances or large volume customers. It also considers the specs of all instance types and automatically launches the cheapest available instance types based on flexible configuration set globally or overridden at the group level using additional tags, but these overrides are often not needed.

A single installation can handle all enabled groups from an entire AWS account in parallel across all available AWS regions, but it can be restricted to fewer regions if desired in certain situations.

Your groups will then monitor and use these spot instances just like they would do with your on-demand instances. They will automatically join their respective load balancer and start receiving traffic once passing the health checks, and the traffic would automatically be drained on termination.

What savings can I expect?

The savings it generates are in the 60-90% range usually seen when using spot instances, but they may vary depending on region and instance type.


What's under the hood?

The entire logic described above is implemented in a set of Lambda functions deployed using CloudFormation or Terraform stacks that can be installed and configured in just a few minutes.

The stack assigns them the minimal set of IAM permissions required for them to work and requires no admin-like cross-account permissions. The entire code base can be audited to see how these permissions are being used and even locked down further if your audit discovers any issues. This is not a SaaS, there's no component that calls home and reveals any details about your infrastructure.

The main Lambda function is written in the Go programming language and the code is compiled as a static binary compressed and uploaded to S3. For evaluation or debugging purposes, the same binary can run out of the box locally on Linux machines or as a Docker container on Windows or macOS. Some people even run these containers on their existing Kubernetes clusters assuming the other resources provided by the stack are implemented in another way on Kubernetes.

The stack also consists of a few CloudWatch event triggers, that run the Lambda function periodically and whenever it needs to take action against the enabled groups. Between runs your group is entirely managed by AutoScaling (including any scaling policies you may have) and load balancer health checks, that can trigger instance launches or replacements using the original on-demand launch configuration.

Read here for more information and implementation details.


Frequently asked questions about the project are answered in the FAQ, please read this first before asking for support.

If you have additional questions not covered there, they can be easily added to the source of the FAQ by editing in the browser and creating a pull request, and we'll answer them while reviewing the pull request.

Getting Started

Just like in the above animation, it's as easy as launching a CloudFormation (or Terraform) stack and setting the (configurable) spot-enabled tag on the AutoScaling groups where you want it enabled to true.

All the required infrastructure and configuration will be created automatically, so you can get started as fast as possible.

For more detailed information you can read this document

Launch latest evaluation build

Warning: it may occasionally be broken or even unavailable, see the below notes for more information.


  • The evaluation binaries launched by the above link are built from git after each commit.
  • They are free of charge but expire after 30 days since the time they were built.
  • They may occasionally be buggy or even unavailable if no code was committed within the last month.
  • Their main purpose is to quickly find issues of the recently committed code and not necessarily to ease installation for new users, which is just a nice side-effect when development is relatively active.
  • To avoind these limitations you can sign up here to get access to the latest stable and supported version that's as easy to install but has no such short expiration.
  • Alternatively you can also build AutoSpotting from the open source code.
  • the Docker images available on DockerHub are also distributed under the same evaluation terms.


Community support is available on the gitter chat room, where the main authors and other users are likely to help you solve issues.

Note: This is offered on a best effort basis and under certain conditions, such as using the latest version of the evaluation builds.

If you need help for a large scale rollout or migrating from alternative tools/solutions, you can purchase a comprehensive support plan guaranteed to save you lots of time and money, if you have any questions you can always get in touch on gitter if you need such help.


Unlike multiple commercial products in this space that cost a lot of money and attempt to lock you in, this project is fully open source and developed in the open by a vibrant community of dozens of contributors.

If this software helps you save any significant amount of money, it would be much appreciated if you could support further development on Github Sponsors.

Financial sponsorship is voluntary, it's also fine if you just try it out and give feedback, report issues, improve the documentation, write some code or assign a developer to work on it, or even just spread the word among your peers who might be interested in it. Any sort of support would be greatly appreciated and would make a huge difference to the project.

Note: Non-trivial code should be submitted according to the contribution guidelines.

Proprietary binaries

The source code is and will always be open source, so you can build and run it yourself, see how it works and even enhance it if you want.

As mentioned before, we also have evaluation binaries that allow you to try it out quickly fof free but come with a few limitations.

To avoid those limitations and also receive access to stable, supported code builds, you can sign up to our inexpensive subscription here.

Individuals and companies supporting the development of the open source code get free of charge support in getting their code merged upstream and upon demand also can get stable build access for a year since their latest contribution to the project.

Proven referrals that manifest through a subscription to the stable builds will be compensated over Paypal with the amount of the first monthly fee of the new subscriber (starting from $29). You can request them on gitter.

Stable build benefits

Installation instructions for the stable builds suitable for Enterprise use will be communicated in private to the stable subscribers as soon as they join and subsequently when new version become available later.

Comprehensive release notes, upgrade instructions and tips to get the most out of AutoSpotting will accompany new stable releases and also made available through the same private communciated channel. These documents will not be communicated to the public audience.

These come with comprehensive support from the author, who will do his best to help you successfully run AutoSpotting on your environment so you can get the most out of it.

The feature requests and issues raised on Github or via private communication channels will be prioritized.

There is also a private forum where stable build users can interact with each other.

Please get in touch on gitter if you have any questions about these stable builds.

Compiling and Installing

It is recommended to use the evaluation or stable binaries, which are easy to install, support further development of the software and allow you to get support.

But if you have some special needs that require some customizations or you don't want to rely on the author's infrastructure or contribute anything for longer term use of the software, you can always build and run your customized binaries that you maintain on your own, just keep in mind that those won't be supported in any way.

More details are available here


Autospotting is already used by hundreds of individuals and organizations around the world and as per internal AWS information a significant(but undisclosed) percentage of all currently running spot instances were launched using it.


This software is distributed under the terms of the OSL-3.0 license.

The official binaries are licensed under this proprietary license.

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