# Conan Center Index: the recipes behind Conan's binary package repository

> Conan Center Index is the source index of recipes for the ConanCenter repository, and it also contains the continuous integration system that turns a pull request into built binary packages. It is a repository of build instructions rather than of binaries, which is why a recipe can change under you and why the remote URL moved in November 2024.

**conan-io/conan-center-index** — Recipes for the ConanCenter repository

- Repository: https://github.com/conan-io/conan-center-index
- Website: https://conan.io/center
- Stars: 1,244 · Forks: 2,516
- Language: Python
- License: MIT
- Published: 2026-10-19 · Updated: 2026-10-19 · Language: en
- Canonical page: https://hysenlabs.com/projects/conan-io-conan-center-index

## A repository of build instructions, not of packages

Conan Center Index is the source index of recipes for the ConanCenter package repository, and the top-level layout makes that plain. There is a recipes/ directory, a docs/ directory, an assets/ directory, and the usual repository furniture including CONTRIBUTING.md and a LICENSE file. The packages themselves are not in this repository.

The build happens elsewhere and automatically. The repository includes a continuous integration system that builds the Conan packages for the recipes submitted via pull request. In other words, the contribution is a recipe, and the CI turns that recipe into binary packages for the configurations it builds.

The repository's primary language is listed as Python, which reflects the tooling around the recipes rather than the content of the packages, since the packages themselves are C and C++ libraries built from source.

The practical model is a registry with a source of truth in version control. A consumer asks for a name and a version, and gets a binary that someone else compiled, along with the recipe that describes how it was compiled. The value is avoiding a native toolchain and a long dependency tree on every machine; the cost is that the recipe, not just the binary, can move.

The licence of the recipes is MIT. The repository is not archived, the last push was on 2026-10-19, and there are no GitHub releases, which is consistent with a repository whose versions live in the Conan remote rather than in tags.

## Two remotes, and the old one stopped moving in November 2024

The remote configuration is the first thing to get right, because Conan 1.x and Conan 2.x installations point at different places.

For Conan 2, the remote URL changed in November 2024 to center2.conan.io, and that new URL has been the default on new installations since Conan version 2.9.2. If you have an older Conan 2 installation, the update is a single command.

```bash
conan remote update conancenter --url https://center2.conan.io
```

Two guarantees come with that remote. New recipe updates are only published to it, and they are only guaranteed to be compatible with recent versions of Conan 2. All previously published recipes and packages known to be compatible with Conan 2 are also served by it, so a fresh remote is not a fresh set of packages.

The legacy remote at https://center.conan.io stopped receiving updates on 4 November 2024. It is frozen and will no longer receive updates, and it is kept in that state only to avoid breaking existing Conan 1.x installations. That is a precise and unusually well explained deprecation, and it settles the question of which remote to configure.

The state of the build system is published separately at status.conan.io, where maintenance, outage or important events related to the CI are announced. A package that will not install is often a CI problem rather than a recipe problem, and that is the first place to look.

## Consuming a package takes one command

The consumer side of the index is deliberately thin. Once Conan is installed, pulling a package from Conan Center is a single command, with an optional generator.

```bash
conan install --require=name/version [-g <generator>]
```

The bracket around the generator part is the README's own notation for the optional argument, and the repository points at the Conan documentation for the details of consuming packages.

That simplicity is what makes the index useful, and it is also what hides the decision you are really making. The version you name is a version of a recipe, and a recipe is a set of build instructions that the maintainers of the index can and do revise. The README states the position in plain language: recipes will evolve over time and, while they are fixing some issues, they might introduce new features and improvements, and your project can break if you upgrade them.

The repository links a document on preventing breaking changes in your project for the way to handle that. The short version is to pin the version you depend on, and to treat a version bump as a change that needs testing rather than as a patch level update.

## CI turns a pull request into a package matrix

The build system is part of the repository, and that is unusual enough to be worth understanding.

A contributor opens a pull request containing a recipe. The continuous integration system in this repository picks it up and builds the Conan packages for it. Whether a recipe is accepted then determines whether a new version appears in the Conan Center remote, which is the pipeline in three steps: recipe, pull request, built package.

The consequence for a consumer is that the binary you get was compiled on infrastructure you do not control, from a recipe that was reviewed by the community, for a matrix of configurations the CI covers. The consequence for a contributor is that the recipe has to be written so that it builds cleanly in that matrix, which is a stricter requirement than building on your own machine once.

The documentation in the repository is organised around those roles. The contributing guide for new recipes is in docs/adding_packages/, the frequently asked questions are in docs/faqs.md, and the internal changes related to the infrastructure are recorded in docs/changelog.md, which is the file to read when a package you used starts behaving differently. There is also docs/community_resources.md, which lists the community lead initiatives.

The one behaviour a consumer should plan for is the recipe changing under a version that your project already uses, and the repository tells you to read the consuming recipes document before you upgrade anything.

## Issue tags are a routing system with three queues

The issue tracker is organised so that reports reach the right queue, and the three tags are worth memorising because they determine what happens next.

For a bug in a package, the instruction is to use the [package] tag in the title, and to specify the name and version in the form zlib/1.2.11 along with the details of the failing configuration, such as the applied profile and the building machine. That specificity matters, because a recipe usually builds for several configurations and a report that names the configuration is one that can be reproduced.

For a request to add a new library, the instruction is to use the [request] label, and to search the issue tracker with that label first in case the library has already been asked for. You then indicate the name and version you would like in the repository, together with links to the project's website, the source download or repository, and anything else that helps create a recipe.

For a CI failure, if you opened a pull request and hit an unexpected error, the first step is to comment in the failing pull request. If the service or the repository is down or failing, you open a new issue with the [service] tag in the title.

There is also a private route. If an issue is not appropriate for public discussion, the repository asks you to contact the maintainers by e-mail at info@conan.io. For a package manager, that is the sensible place for a security report.

The gap between the two queues is worth noticing. A request is a promise to create a recipe, and the timeline for that is not specified anywhere in the documentation.

## The MIT licence covers the recipes, not every file inside them

The licence section is short and precise, and it contains the one legal wrinkle in this repository. All the Conan recipes are distributed under the MIT licence. Other files, such as patches or examples used to test the packages, can use different licences, and for those files the specific licence and credit must be checked in the file itself.

That is a narrower grant than the repository-level MIT badge suggests, and it is the kind of detail that matters if you copy a patch into your own project rather than depending on a built package. A patch that fixes a build on one platform often comes from that platform's vendor, and the recipe that applies it is MIT while the patch is not.

Practically, the check is easy. Look at the file you are taking rather than at the LICENSE file at the root, and keep the attribution the file asks for.

The alternative approach to the same goal is instructive. A team can build the same libraries itself, from the same upstream sources, with its own toolchain, and then it controls the binaries, the patches and the licences, and it accepts the cost of a native build on every machine and every platform. Conan Center Index removes that cost in exchange for depending on a remote, on recipes that evolve, and on a set of prebuilt configurations rather than your own.

## Conclusion

Conan Center Index fits a C or C++ team that wants to consume prebuilt packages with a known version and a known configuration instead of compiling every dependency on every machine, and that is willing to pin versions in exchange for the occasional breaking recipe change. It does not fit a project that must vendor every byte of its dependency tree, that cannot accept a package built on someone else's infrastructure, or that is still on Conan 1.x and expects new recipes. Verify three things first: that your Conan installation points at the https://center2.conan.io remote, since the legacy one has been frozen since 4 November 2024, the exact version you pin, because recipes evolve and the repository says so plainly, and the licence of any patch or example file you copy out of a recipe, since the MIT licence covers the recipes and not necessarily every file inside them.

## FAQ

### Which Conan remote should I use for Conan 2?

Use https://center2.conan.io, which became the default for new installations with Conan 2.9.2. To update an existing installation, run conan remote update conancenter --url https://center2.conan.io. The legacy remote at https://center.conan.io stopped receiving updates on 4 November 2024 and exists only to avoid breaking Conan 1.x installations.

### How do I install a package from Conan Center?

Run conan install --require=name/version, optionally with a generator. The repository links the Conan documentation for the details of consuming packages, and warns that recipes evolve over time, so a version you depend on can change in ways that break your project.

### How do I report a bug in a package recipe?

Open an issue with the [package] tag in the title, name the package and version in the form zlib/1.2.11, and give the details of the failing configuration such as the applied profile and the building machine. If the failure is in the CI itself rather than in your recipe, comment on the failing pull request, and use the [service] tag if the whole service is down.

### How do I request a new library in Conan Center?

Open an issue with the [request] label, and search the issue tracker with that label first in case the library was already requested. Indicate the name and version you would like, and include links to the project website and the source download or repository, plus anything else that helps someone write the recipe.

### What licence applies to Conan Center recipes?

All recipes are distributed under the MIT licence. Other files in the repository, such as patches or examples used to test the packages, can carry different licences, and for those the specific licence and credit must be checked in the file itself.

## Sources

- [conan-io/conan-center-index on GitHub](https://github.com/conan-io/conan-center-index)
- [Issues](https://github.com/conan-io/conan-center-index/issues)
- [License: MIT](https://github.com/conan-io/conan-center-index/blob/master/LICENSE)
- [Project website](https://conan.io/center)
- [README](https://github.com/conan-io/conan-center-index/blob/master/README.md)

---

Hysen Labs editorial analysis, written from the project's own repository and release notes. Cite the canonical page: https://hysenlabs.com/projects/conan-io-conan-center-index