ActivityPub debugging platform
Debugging tools for the fediverse.
DrFed is a web-based platform for developing and debugging ActivityPub implementations—inspecting objects and activities, and tracing where federation fails. It is built by the team behind Fedify.
In active development; not yet released.
The problem
“Why doesn’t my server talk to Mastodon? Why did Lemmy reject this activity?”
Answering questions like these usually means combining several tools, or working from guesswork. When federation breaks, it is hard to tell whether the cause is a signature, JSON-LD processing, a WebFinger lookup, or a request that never arrived. DrFed brings these stages together in one place, so you can see where interoperability breaks down.
Seven tools for ActivityPub development.
Each one focuses on a part of ActivityPub that commonly differs between implementations.
- 01
object-lookupObject lookup
Fetch and inspect any ActivityPub object by URL or handle—in compact, expanded, or raw JSON-LD views, with linked objects dereferenced automatically.
- 02
activity-monitorActivity monitor
Receive and inspect incoming activities in real time, with a searchable, filterable history of what your inbox received.
- 03
failure-diagnosticsFailure diagnostics
Identify which stage of federation failed—DNS, TLS, HTTP, signatures, or JSON-LD—with structured errors and suggested fixes.
- 04
webfinger-nodeinfoWebFinger & NodeInfo testers
Validate WebFinger and NodeInfo responses and check for common CORS and schema misconfigurations.
- 05
jsonld-toolkitJSON-LD toolkit
Compact, expand, and compare how different implementations read the same document, so you can find where terms are dropped.
- 06
http-signaturesHTTP signatures debugger
Step through signature construction and verification stage by stage. Supports both draft-cavage and RFC 9421.
- 07
activity-builderActivity builder
Construct and send test activities to any inbox, with templates and validation for common activity types.
- +
plannedMore to come
Self-hosting, documentation, and interoperability testing against Mastodon, Misskey, and Lemmy are planned for later milestones.
See the roadmap
Development milestones.
DrFed’s development is organized into ten milestones, funded by NLnet’s NGI0 Commons Fund.
-
The core tools
Object lookup, activity monitor, failure diagnostics, WebFinger & NodeInfo testers, the JSON-LD toolkit, the HTTP signatures debugger, and the activity builder.
-
Self-hosting & docs
Single-image Docker deployment with built-in tunnel support, hosted-service infrastructure, and documentation and tutorials.
-
Interoperability validation
Testing against Mastodon, Misskey, Lemmy and more, edge-case handling, and integration of community feedback.
-
Polish & public launch
Accessibility and UX refinements, performance optimization, and a finalized public release.
Hosted, or self-hosted.
DrFed is free and open source under the AGPL-3.0. Use the hosted service, or run it on your own infrastructure.
Hosted service
Nothing to install; paste a URL and start debugging. Useful for investigating a production issue without setting up infrastructure first.
Self-hosted
A single Docker image with built-in tunnel support, an embedded Postgres database (PGlite) by default, and pluggable storage backends, for private or persistent deployments.
Built by the people behind Fedify.
DrFed is made by the maintainers of Fedify, the TypeScript ActivityPub framework used by Ghost and others. The same experience building and debugging federated software informs how DrFed is designed.
-
ChanHaeng Lee
@2chanhaeng@hackers.pub -
Hong Minhee
@hongminhee@hollo.social -
Hyeonseo Kim
@gaebalgom@hackers.pub -
Jiwon Kwon
@z9mb1@hackers.pub
Follow DrFed’s progress.
DrFed is still in development. Subscribe to hear about releases, early access, and progress along the way.
Occasional updates only; unsubscribe anytime. You can also follow @drfed@hackers.pub on the fediverse.