Tessera v1.0 is here

The TrustFabric team at Google are thrilled to announce that Tessera, the C2SP tlog-tiles compliant transparency log library, is now generally available!

For over a decade our team has been building and running transparency logs. What began with purpose-built Certificate Transparency (CT) logs soon led to the generalisation and broader adoption of these principles by other ecosystems. To encourage and facilitate this adoption we provided a general purpose transparency log implementation, Trillian, which has underpinned ecosystems like CT, Go's SumDB, and Sigstore ever since.

The growth and success of these ecosystems has driven demand for transparency logs that support higher throughput while also being cheaper and easier to operate. Tessera is now ready to meet that demand.

Key Features

• Ease of use: As a library rather than a microservice architecture, Tessera is built directly into application code. This gives you the freedom to build and deploy your application in the way that makes most sense for you.

• Tiles API: The C2SP tlog-tiles API is central to Tessera, helping you to build transparency-enabled applications that automatically benefit from many of the lessons learned over the last 10 years, and can easily integrate with shared services such as witnessing.

• Scalable architecture: Our design philosophy enables Tessera to play to the strengths of the target environment. Writes take an idiomatic approach, and reads are highly cacheable and, in many cases, able to be served directly from the underlying infrastructure.

• Multi-environment support: Logs built with Tessera can run natively in Cloud (GCP or AWS), or on-prem with Vanilla S3+MySQL or POSIX filesystem backends.

• Resilience and Availability: Applications can run multiple instances without compromising log storage, resulting in improved service resilience and availability in the face of frontend issues.

• Customizable log personalities: You can build transparency applications tailored to your specific use-case.

• Integrated support for witnessing: C2SP-compliant witnessing is supported out of the box, allowing easy integration with either the growing public witness network, or private witnesses.

• Reliable support: Tessera v1.0 is released with the Google Open Source breaking changes policy, meaning reliable library maintenance and support.

Performance

Tessera has proven to be stable at a high-throughput of writes in both our own testing environment, as well as long-running instances of our Tessera-based Certificate Transparency log implementation, TesseraCT.

With write-throughputs in excess of 10,000 entries per second backed by POSIX, and 5,000 entries/s on GCP, Tessera scales to meet most deployment scenarios. More detailed notes are available in the repo, and in the article by IPng discussing their own Tessera-based deployment.

Getting started with Tessera

Tessera is the path we recommended for building new transparency logs. To get started, check out the Codelab for a simple step-by-step guide to setting up your first log, writing a few entries to it, and then inspecting its contents.

Here's what others have to say:

• "Tessera has provided a fantastic developer experience while building the next version of Sigstore's signature transparency log. We've been able to scale up easily and reduce complexity in our infrastructure."

  -- Sigstore TL

• "Tessera was a breeze to work with! The API is straightforward and the storage backends are easy to import and swap for development and production."
  -- Adit Sachde

• "IPng Networks in Switzerland has deployed the first self-hosted Tessera-based static CT log, and reported a successful deployment in the Certificate Transparency community. The underlying Tessera library is blazingly fast compared to alternatives, reaching easily 18K leaves/sec, while the global WebPKI throughput is two orders of magnitude smaller. TesseraCT, built on this library, scales very well, allowing for fine grained configuration and off the shelf tools like nginx to serve the read-path. More details in https://ipng.ch/s/articles/2025/08/24/certificate-transparency-part-3-operations/ ."
  -- IPng Networks

We’d love to hear from you!

If you have any questions or would like guidance on working with Tessera please reach out to the team by posting questions on the transparency.dev community slack. We’re here to help, and hope that Tessera 1.0 will be instrumental in improving the verifiability of your systems.