Compatibility
tsz is close to tsc compatibility across diagnostics, emit, and editor behavior. The remaining work is concentrated in real-project compile readiness and the last release-gate gaps tracked below.
Currently tracking TypeScript 7.0.2.
Type Checking
The conformance suite compares tsz diagnostics with tsc on TypeScript's own compiler tests. This is the main signal for whether tsz agrees with tsc about types and errors.
Type checking
11,657 of 12,043 compiler tests match tsc.
Emit
Emit compatibility means the generated output matches what TypeScript users expect from tsc. JavaScript emit and declaration emit are tracked separately because they fail for different reasons and matter to different users.
JavaScript emit
Declaration emit
JavaScript emit is at 100.0%. Declaration emit is at 99.1%.
Language Service
The language-service suite checks editor-facing behavior: completions, hover, go-to-definition, diagnostics, and related workflows that developers feel in an IDE.
Editor behavior
6,562 of 6,562 editor tests match the TypeScript suite.
Project compatibility
These rows track real project fixtures that tsc accepts. A green row means tsz completed the same project check; red or yellow rows identify the current compatibility blocker. A "Not measured" row is a defined corpus project with no measurement in the latest artifact.
9 of 69 defined corpus rows measured · 60 not measured.
| utility-types | Passing | 1,012 lines | no ambient stubs | exit success | check | 5 files | 63 MiB peak |
| ts-essentials | Passing | 3,903 lines | no ambient stubs | exit success | check | 95 files | 38 MiB peak |
| RxJS | Passing | 20,151 lines | no ambient stubs | exit success | check | 240 files | 34 MiB peak |
| type-fest | Not measured | — | no ambient stubs | runner error | fixture setup | 0 files | — |
| ts-toolbelt | Passing | 8,044 lines | no ambient stubs | exit success | check | 242 files | 33 MiB peak |
| Zod | Errors | 4,333 lines | no ambient stubs | nonzero exit | check | 8 files | 173 MiB peak |
| Kysely | Not measured | — | no ambient stubs | runner error | fixture setup | 0 files | — |
| type-challenges solutions | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| generated Vite app | Passing | 86 lines | no ambient stubs | exit success | check | 4 files | 115 MiB peak |
| generated Next app | Passing | 282 lines | no ambient stubs | exit success | check | 7 files | 111 MiB peak |
| large-ts-repo | Timeout | 1,288,641 lines | no ambient stubs | timeout | timing | 6,061 files | — |
| Next.js full project | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| Valibot | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| MSW | Not measured | — | 19 stubbed modules, 296 any members | missing or incomplete artifact | artifact | — | — |
| Comlink | Passing | 814 lines | no ambient stubs | exit success | check | 3 files | 93 MiB peak |
| Effect | Not measured | — | 2 stubbed modules, 14 any members | missing or incomplete artifact | artifact | — | — |
| Drizzle ORM | Not measured | — | 44 stubbed modules, 1013 any members | missing or incomplete artifact | artifact | — | — |
| ts-rest | Not measured | — | 2 stubbed modules, 60 any members | missing or incomplete artifact | artifact | — | — |
| ofetch | Not measured | — | 2 stubbed modules, 5 any members | missing or incomplete artifact | artifact | — | — |
| ts-pattern | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| radash | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| valtio | Not measured | — | 3 stubbed modules, 55 any members | missing or incomplete artifact | artifact | — | — |
| scule | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| mitt | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| change-case | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| tiny-invariant | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| ts-belt | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| ts-extras | Not measured | — | 1 stubbed module, 92 any members | missing or incomplete artifact | artifact | — | — |
| superjson | Not measured | — | 1 stubbed module, 8 any members | missing or incomplete artifact | artifact | — | — |
| tRPC | Not measured | — | 7 any members | missing or incomplete artifact | artifact | — | — |
| TanStack Query | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| TanStack Router | Not measured | — | 6 stubbed modules, 74 any members | missing or incomplete artifact | artifact | — | — |
| Zustand | Not measured | — | 4 stubbed modules, 18 any members | missing or incomplete artifact | artifact | — | — |
| Jotai | Not measured | — | 3 stubbed modules, 45 any members | missing or incomplete artifact | artifact | — | — |
| fp-ts | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| io-ts | Not measured | — | 2 any members | missing or incomplete artifact | artifact | — | — |
| Immer | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| Remeda | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| ts-morph | Not measured | — | 2 stubbed modules, 18 any members | missing or incomplete artifact | artifact | — | — |
| ArkType | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| Superstruct | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| Runtypes | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| HotScript | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| TypeBox | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| class-transformer | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| TypeGraphQL | Not measured | — | 13 stubbed modules, 156 any members | missing or incomplete artifact | artifact | — | — |
| neverthrow | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| XState | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| MobX | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| umami | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| excalidraw | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| dub | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| formbricks | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| typebot | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| lobe-chat | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| supabase-studio | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| infisical | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| payload | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| medusa | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| outline | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| trigger-dev | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| joplin | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| directus | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| n8n | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| cal-com | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| documenso | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| affine | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| immich-server | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |
| rocketchat | Not measured | — | no ambient stubs | missing or incomplete artifact | artifact | — | — |