OISY Signer changes its URL

The OISY Signer, the client a dapp is interacting with when connecting to OISY via the signer standard, is changing its URL

• 🔴 from: oisy.com/sign

• ✅ to: signer.oisy.com or legacy-signer.oisy.com

_{Note that there is no more /sign path in the new URLs}

When will this happen

• The new URLs are ready and can be used right away

• The previously used URL (oisy.com/sign) will remain supported until May 31, 2026

Why are we doing this?

End of 2025, a new version of the @dfinity/agent, v5, was introduced, which is not fully backward compatible with previous versions. And @slide-computer/signer, the almost exclusively used typescript library for signer interaction on the Internet Computer (later migrated to @icp-sdk/signer), upgraded from v4.0.0 to v4.1.0 to include this new agent version.

There is a known incompatibility with the new agent that causes a specific combination of wallets and dapps to fail.

Dapps that still use the agent v4 fail to connect to a wallet that already uses v5.

This would block OISY from upgrading to the agent v5, until all dapps have upgraded to the latest @icp-sdk/signer version.

To allow dapps to upgrade at their own pace, we decided to offer new signer URLs that allow all dapps to connect to a matching version of the OISY Signer.

• use signer.oisy.com if you have already migrated to the @icp-sdk/signer v4.1.0 or later

• use legacy-signer.oisy.com otherwise

So all you need to do is to override the OISY Signer URL.

⚠️ Note that the 2 new signer URLs do not have a /sign anymore!

We are currently working on getting those changes directly in the underlying libraries, but this might take a bit longer to trickle fully through, since additional 3rd part libraries are involved (nfid identity kit, windoge98/pnp, ...). We will update all known versions that contain the new URLs.

Is our App affected by this?

YES, you are affected if you offer a signer standard connection to OISY

The OISY Signer URL change affects all relying parties. You either need to change the OISY Signer URL in your codebase, or ensure you have a latest version of a library that has the new URL already set.

What do we need to do?

Dapps that already use the agent v5, e.g. via the @slide-computer/signer v4.1.0 or later, can interact with all wallets (agent v4 or v5)

• Change your OISY Signer URL to signer.oisy.com

Dapps that still use v4 of the agent, e.g. via an earlier version of the @slide-computer/signer library, only work with wallets that also still use the agent v4.

• Change your OISY Signer URL to legacy-signer.oisy.com

• Plan an upgrade to a library that supports the agent v5, and then change the signer URL accordingly

What's the timeline?

This changes should be done before May 17, 2026. After that date, the old OISY Signer URL (oisy.com/sign) will not be supported anymore

The legacy-signer URL will not be supported much longer. It's planned to be decommissioned latest in Q3 2026. So ensure to upgrade your library and switch to the signer.oisy.com URL.

What library versions contain the updated URLs?

Library	Versions
@nfid/identitykit	-
@windoge98/plug-n-play	-

Additional note

This separation between OISY (oisy.com) and the OISY Signer (signer.oisy.com) also solves the issue that the signer standard fails to communicate between a dapp and a wallet if both are installed as PWA on mobile devices.

With the new setup, a user can install a dapp and OISY as PWA, and then the dapp starts a connection to the OISY Signer, a new browser window in opened instead of the OISY PWA.