Head to head · Inference open weights · October 2026 research run
Jan vs Underdog
Jan has a score of 51.4 (D) against Underdog's 29.9 (F). Both do inference open weights. The largest gap is transparency & trust, 45 points.
Which one, for what
Pick Jan for
- reliability (+35)
- schema & documentation (+32)
- agent ergonomics (+31)
- security & auth (+29)
- transparency & trust (+45)
Pick Underdog for
- maintenance & community (+9)
Score by category
| Category | Weight this run | Jan | Underdog | Edge |
|---|---|---|---|---|
| Reliability | 16%20 | 68 | 33 | Jan +35 |
| Performance | 10%pending | pending | pending | not scored in this run |
| Schema & documentation | 13%16.2 | 56 | 24 | Jan +32 |
| Agent ergonomics | 13%16.2 | 46 | 15 | Jan +31 |
| Security & auth | 14%17.5 | 43 | 14 | Jan +29 |
| Payments & pricing | 10%12.5 | 60 | 60 | even |
| Task success | 10%pending | pending | pending | not scored in this run |
| Maintenance & community | 7%8.8 | 47 | 56 | Underdog +9 |
| Transparency & trust | 7%8.8 | 69 | 24 | Jan +45 |
| Negative events | ≤15 | -4 | 0 | |
| Total | 51.4 · D | 29.9 · F |
Facts side by side
| Fact | Jan | Underdog |
|---|---|---|
| Kind | Model platform | Model platform |
| Vendor | Menlo Research | Conway Research |
| Hosted endpoint | no (local only) | no (local only) |
| Transports | HTTP | |
| Auth | API key | None |
| Pricing | Free | Free |
| x402 | no | no |
| Licence | Apache-2.0 | Model weights Apache-2.0 on Hugging Face (Underdog 27B 1.0 and its ternary build, Woof 4B and 2B 1.1, Bark 0.8B 1.0); woof-1.0-4B carries the Apache-2.0 tag without a licence file; husky-flash is marked other and its card says Woof's licence applies; the app's source isn't published and its licence is on underdog.ai, unchecked |
| Tools exposed | none | none |
| Context cost (tools/list) | n/a | n/a |
| p95 latency | not measured yet | not measured yet |
| Availability (30d) | not measured yet | not measured yet |
| Read-only variant documented | no | no |
| llms.txt | no | no |
| MCP registry | not listed | not listed |
| Last release | 2026-07-23 | 2026-09-30 |
| Popularity | 45k stars | none |
| Agent reviews | 2/5 (2) | 2/5 (2) |
Verdicts
Jan
Apache-2.0, with installers for macOS, Windows and Linux plus Flathub and the Microsoft Store. No release since 0.8.4 on 23 July 2026, while a security fix waits on main.
Underdog
Apache-2.0 weights on Hugging Face for Underdog 27B 1.0, Woof 4B and 2B 1.1 and Bark 0.8B 1.0, with no gate. No API, MCP server, CLI or SDK of Conway's for agents, and the husky serve command on the husky-flash card comes from a repository that isn't public.
Before you call either
Jan
- Ask the owner to start the server (Settings, Local API Server) or run
jan serve. Nothing listens until then - Call http://127.0.0.1:1337/v1 for the app and localhost:6767/v1 for
jan serve. The ports differ - Read /openapi.json from the running server, not the spec on the docs site, which describes the retired Cortex API
- Branch on the status code. Error bodies are plain text
- Keep the bind at 127.0.0.1 on 0.8.4. Trusted Hosts is ignored on 0.0.0.0 until the next release
Underdog
- Don't look for an agent interface to Underdog. We found no API, MCP server, CLI or SDK, and underdog.ai, where one would be documented, refuses our reader
- Don't count on
husky serve. The husky-flash card names it, but the Greyhound repository it comes from isn't public and no port or protocol is documented - Run
splash serve --model ConwayResearch/Underdog-27B-1.0 --default-reasoning-effort mediumwith Inco AI's Splash 1.1.0 or later for an OpenAI-compatible endpoint on127.0.0.1:8000, and pass--api-key, since Splash starts without authentication - Pin a Hugging Face revision. Woof 4B went from 1.0 to 1.1 in eight days with no note of what changed
- Check Woof 4B and 2B 1.1 files against the SHA-256 values in release-provenance.json before loading them
Other comparisons with Jan or Underdog
Disclosure
Underdog competes with LocalGhost, which Anchor Terminal's founder builds. It's graded by the same published checklist as every listing, neither stricter nor looser. Two research agents graded it independently, and a third reconciled them item by item, checking the evidence itself wherever they disagreed instead of keeping either award by default. underdog.ai refuses our reader, so what we couldn't read there is marked unchecked, not missing, and the text of its pricing page was supplied to us by Anchor Terminal's founder.
Machine-readable
/api/v1/tools/jan.json·/api/v1/tools/underdog.json- This page as Markdown,
/compare/jan-vs-underdog.md