Bun API Coverage Matrix — Patties Framework

• Source: https://bun.com/llms-full.txt (54,408 lines)
• Fetched: 2026-05-23
• Last reclassified: 2026-05-31
• Specs audited: agent_specs/framework/archive/phase-{0..4}/*.md, agent_specs/framework/archive/{00-overview,13-conventions,19-request-id,20-server-timing,21-embedded-files}.md, agent_specs/framework/draft/{17-dev-island-bundler,18-dev-island-bundler-impl,22-image-pipeline,23-markdown-pages,24-bun-builtin-policy}.md, agent_specs/cli/{draft,archive}/*.md (35 files total). Specs 19, 20, and 21 shipped and moved progress/ → archive/ on 2026-05-30.
• Raw text: agent_specs/research/bun-surface-raw.txt

The catalogue covers every Bun.* global, every bun:* built-in module, the notable bun CLI verbs/flags, and Bun-specific language features (import attribute types, HMR import.meta, embedded files) found in llms-full.txt. Classification reflects whether a Patties spec currently names the API, whether it should, or whether it belongs outside the framework's surface.

Summary

The nineteen encoded rows correspond to accepted RFCs in rfcs/accepted/. As of 2026-05-31 a fourth RFC bucket exists: rfcs/out-of-scope/ for permanently-dismissed-but-discovered APIs (distinct from deferred/, which stays revisitable on a named trigger). Every rfc-later row has a corresponding stub RFC in rfcs/backlog/ (7 files) so the matrix and the RFC tree stay in lockstep. No new relevant-gap items were found in this refresh.

Two RFC families share the rfcs/ tree. This matrix tracks the rfc-bun-* family (Bun-API coverage). A second family, rfc-patties-ui-*, tracks shadcn-parity for the copy-in UI catalog and is tracked by a separate matrix — patties-ui-parity-matrix.md. The two families do not overlap: rfc-bun-* is about which Bun primitive a framework feature reaches for; rfc-patties-ui-* is about which shadcn scaffold capability patties-ui ships. When auditing rfcs/{accepted,backlog,deferred,out-of-scope}/, filter by prefix — counts in this matrix's summary cover rfc-bun-* only. Current patties-ui RFCs: 8 accepted (rfc-patties-ui-{update-diff,config-block,add-path,view,init,migrate,theming,registries}), 0 backlog, 0 deferred, 1 out-of-scope (rfc-patties-ui-theme-editor, moved 2026-05-31).

2026-05-31 changes (RFC-disposition pass + new out-of-scope/ bucket):

• New bucket rfcs/out-of-scope/ — permanent "considered & dismissed" home, distinct from revisitable deferred/.
• Moved backlog → out-of-scope the four verdict: defer (borderline out-of-scope) rows that only sat in backlog because no out-of-scope bucket existed: Bun.connect/listen ([[rfc-bun-tcp]]) + Bun.udpSocket ([[rfc-bun-udp]]) — raw sockets are below a HTTP-only framework's altitude; Bun.peek ([[rfc-bun-peek]]) — internals-only, never user-facing; Bun.fileURLToPath/pathToFileURL ([[rfc-bun-path-url]]) — identical to node:url, nothing to own. rfc-later count 11 → 7.
• Encoded Bun.task-cache composition → [[rfc-bun-task-cache]] (accept) → framework/27-task-runner-cache (Bun-native monorepo task-output cache + affected detection; RFC filed draft→accepted/). (new catalogued row, +1 total)
• Encoded bun audit / outdated / which (lifecycle) → [[rfc-bun-package-hygiene]] (accept, pulled forward to 0.1.x) → new spec cli/20-doctor (patties doctor project-hygiene checks). Lands the "doctor cluster" — reuses Bun.which ([[rfc-bun-which]]) + Bun.stringWidth/stripANSI/wrapAnsi (spec 24 §24.2). deferred → accepted/.
• Promoted to backlog bun pm catalogs/workspaces → [[rfc-bun-pm]] — its named trigger fired (spec 18 --monorepo + specs 26/27 now exercise Bun workspaces/--filter/catalogs). deferred → backlog/.
• Moved to out-of-scope (permanent no): Bun.color → [[rfc-bun-color]] (no consumer — patties-ui theming ships pre-authored tokens.css, never parses color) and Bun.sleep → [[rfc-bun-sleep]] (trivial setTimeout wrapper, no slot). deferred → out-of-scope/. Also rfc-patties-ui-theme-editor (ui family) → out-of-scope/ (visual editor is community/app-level; distribution already covered by [[rfc-patties-ui-registries]]).
• Confirmed deferred, trigger retargeted Bun.YAML/TOML/JSON5 → [[rfc-bun-config-formats]] — revisit when the plugin/deploy-adapter surface ([[framework/phase-4/09-plugins]]) wants vendor config through the loader.
• Reaffirmed deferred: [[rfc-bun-cookie-signing]] — better-auth (bring-your-own backend, per spec 19) owns auth cookie signing, so it's not needed for auth; kept deferred only for a possible non-auth signed-cookie need (flash messages, signed prefs). [[rfc-bun-html-imports]] — "ok for now"; scheduled re-eval after spec 18 ships.

2026-05-27 changes:

• New draft specs framework/draft/17-dev-island-bundler and framework/draft/18-dev-island-bundler-impl audited — introduce no new Bun APIs (use already-covered Bun.build, bun --hot, Bun.serve routes, Bun.file). Spec 17's "Future re-evaluation" section gives the deferred [[rfc-bun-html-imports]] a concrete trigger to revisit (one release cycle after spec 18 ships).
• Promoted Bun.randomUUIDv7 from rfc-later → encoded via [[rfc-bun-random-uuidv7]] (accept) → framework/draft/19-request-id (new spec; supersedes the relevant slices of the archived phase-1 middleware and phase-3 agents specs).
• Bucket-A acceptance pass. Promoted three rfc-later rows to encoded:
  • Bun.nanoseconds → [[rfc-bun-nanoseconds]] (accept) → framework/draft/20-server-timing (dev-only Server-Timing: total;dur=<ms> header; extends the spec-19 response finalizer).
  • Bun.which → [[rfc-bun-which]] (accept) → cli/draft/10-scaffold-probes (bun-fail + git-warn probes for create-patties; additive to spec 09).
  • Bun.embeddedFiles → [[rfc-bun-embedded-files]] (accept) → framework/archive/21-embedded-files (single-binary deploy with embedded static assets; only Bun-only structural unlock in the bucket).
• Bucket-A defer pass. Promoted two rfc-later rows to deferred (full RFCs with re-evaluation triggers):
  • Bun.Cookie cookie signing → [[rfc-bun-cookie-signing]] (reject-for-v1) — no auth/session consumer in the codebase; users can compose Bun.CryptoHasher + ctx.cookies manually.
  • Bun.YAML / Bun.TOML / Bun.JSON5 → [[rfc-bun-config-formats]] (reject-for-v1) — preserve the TS-first config virtue; no demand signal yet.
• Bucket-B "Bun-builtin dep-replacement" sweep. Reframed the matrix lens — patties' value isn't "do what Next can't" but "do what every Node framework does, with a fraction of the dependency surface." Promoted five more rfc-later rows to encoded:
  • Bun.Image → [[rfc-bun-image]] (accept) → framework/draft/22-image-pipeline (next/image-class pipeline: build-time variants + signed runtime endpoint + disk LRU cache, no Sharp dep).
  • Bun.markdown → [[rfc-bun-markdown]] (accept) → framework/draft/23-markdown-pages (.md/.mdx routes with constrained-MDX islands support, no remark/rehype/MDX dep stack).
  • Bun.Archive → [[rfc-bun-archive]] (accept) → framework/draft/24-bun-builtin-policy § 24.1 (tar/zip for deploy plugins, no tar/archiver dep).
  • Bun.stringWidth / stripANSI / wrapAnsi → [[rfc-bun-cli-ansi]] (accept) → framework/draft/24-bun-builtin-policy § 24.2 (CLI text formatting, no chalk-ecosystem dep).
  • Bun.hash / Bun.sha → [[rfc-bun-hash]] (accept) → framework/draft/24-bun-builtin-policy § 24.3 (one-shot hashing; Bun.CryptoHasher still owns streaming).
• Bucket-B defer pass. Promoted four rfc-later rows to deferred (full RFCs with re-evaluation triggers):
  • Bun.sleep / Bun.sleepSync → [[rfc-bun-sleep]] (reject-for-v1) — trivial userland; no framework slot.
  • Bun.color → [[rfc-bun-color]] (reject-for-v1) — patties is a framework, not a design system.
  • bun pm (catalogs/workspaces) → [[rfc-bun-pm]] (reject-for-v1) — no monorepo demand; revisit when a real multi-app patties project lands.
  • bun patch / audit / outdated → [[rfc-bun-package-hygiene]] (reject-for-v1) — needs patties doctor as host, which doesn't exist yet.
• Created rfcs/backlog/ and seeded it with stub RFCs — one per rfc-later row. As of the bucket-A pass above, 22 stubs remain in rfcs/backlog/ (down from 24). Each stub carries the same Bun-unique / comparable / trigger metadata as the matrix row, so future promotions can edit one place (the RFC) and update the matrix from it.
• Tables expanded with two new columns: Bun-unique? (does Bun unlock this, or could Next on Node do it?) and Comparable elsewhere (closest analog in Next.js / Remix / SvelteKit / Astro). See the legend below.
• Fixed off-by-N counts in the summary table — the previous totals (94, 26, 23) didn't match the actual row counts. The numbers above are computed from the tables.

2026-05-30 changes (spec-location only; no reclassification):

• Bun.randomUUIDv7 / Bun.nanoseconds shipped (commit 91848f2). Their host specs moved progress/ → archive/ with status: completed: framework/19-request-id, framework/20-server-timing. Both stay encoded; the matrix pointers and the encoded_in / host_subsystem fields in [[rfc-bun-random-uuidv7]] / [[rfc-bun-nanoseconds]] now point at framework/archive/.
• Bun.embeddedFiles shipped (commit 37645e9). Its host spec moved progress/ → archive/ with status: completed: framework/21-embedded-files. Stays encoded; the matrix pointer and the encoded_in field in [[rfc-bun-embedded-files]] now point at framework/archive/.

How to read the Bun-unique column

This column answers: "could a Node-based meta-framework (Next.js, Remix, SvelteKit, Astro) do the same thing?"

• Bun-only — Node has no comparable API, or only via experimental flags / native addons that are awkward to ship. Bun genuinely unlocked this; a framework on Node can't ship it without significant ceremony. This is where the choice of Bun pays off.
• Bun-faster — Same conceptual API exists on Node; Bun's implementation is materially faster (often by orders of magnitude — bun install vs npm install, Bun.spawn vs child_process.spawn). Capability is not new.
• Bun-builtin — Node could but you'd install a library; Bun ships it as a global or module. Removes a dependency and its maintenance surface (Bun.password vs bcrypt, Bun.semver vs semver npm).
• Standard — WHATWG / web / Node-standard API with no Bun-specific advantage (Bun.env ≈ process.env, Bun.gzipSync ≈ zlib.gzipSync).
• n/a — internal, joke, or false-positive entry; no comparison meaningful.

The framework's value proposition spans both Bun-only and Bun-builtin categories — both are legitimate wins. Bun-only items (embedded-files, HTMLRewriter, serve-routes, hot-reload) deliver capabilities Next-on-Node fundamentally cannot ship. Bun-builtin items (Image, markdown, cookies, cron, secrets, archive, ANSI helpers, hash) deliver capabilities Next-on-Node ships via heavy native addons (Sharp 30+MB, bcrypt) or multi-package dep stacks (remark/rehype/MDX, chalk-ecosystem); patties ships them with a fraction of the install footprint and faster cold-start.

The framing the matrix codifies (set 2026-05-27 after the bucket-A passes): patties isn't "Next.js, but with Bun-exclusive features." It's "Next.js, rebuilt knowing Bun exists — same capabilities, smaller dep surface, faster boot." The 17 encoded RFCs reflect this — most are Bun-builtin replacements of common Node ecosystem libs, not Bun-only unlocks.

Matrix

Encoded (accepted RFCs that have landed in a spec)

Deferred (RFC drafted but rejected for v1)

Covered (APIs already used by a spec — no RFC needed)

RFC-later (backlog — useful, not blocking phases 0–4)

Every row below has a corresponding stub at rfcs/backlog/rfc-bun-<slug>.md. The stub holds the same Bun-unique / comparable / trigger metadata in YAML frontmatter so it can be promoted to rfcs/draft/ and edited in place when the trigger fires.

Out-of-scope (not framework surface)

Re-running this audit

# 1. Refresh raw text
mkdir -p agent_specs/research
curl -fsSL https://bun.com/llms-full.txt \
  -o agent_specs/research/bun-surface-raw.txt
# (fallback: https://bun.sh/llms-full.txt, then sitemap.xml)

# 2. Extract candidate APIs
cd agent_specs/research
grep -ohE 'Bun\.[A-Za-z_][A-Za-z0-9_]*' bun-surface-raw.txt | sort -u > _bun-globals.txt
grep -ohE 'bun:[a-z_][a-z0-9_]*'         bun-surface-raw.txt | sort -u > _bun-modules.txt
grep -ohE 'bun [a-z][a-z-]*'              bun-surface-raw.txt | sort | uniq -c | sort -rn > _bun-cli.txt

# 3. Cross-reference against specs (current layout: archived phase specs +
#    in-flight drafts under framework/draft/ and cli/draft/)
cd ..
grep -rohE '(Bun\.[A-Za-z_][A-Za-z0-9_]*|bun:[a-z_]+|bun --?[a-z-]+|HTMLRewriter)' \
  framework/archive/phase-*/*.md \
  framework/archive/00-overview.md framework/archive/13-conventions.md \
  framework/draft/*.md \
  cli/archive/*.md cli/draft/*.md \
  | sort | uniq -c | sort -rn

# 4. Re-classify entries → update this matrix
# 5. Diff against rfcs/{accepted,deferred,backlog}/rfc-bun-* — each RFC carries
#    Bun-unique / comparable / trigger metadata in YAML frontmatter that
#    must match the matrix row. Promote backlog → draft → accepted as
#    triggers fire. NOTE: restrict to the rfc-bun-* prefix — the rfc-patties-ui-*
#    family in the same dirs belongs to patties-ui-parity-matrix.md, not here.
ls agent_specs/rfcs/{accepted,backlog,deferred}/rfc-bun-*

Reviewer note: filter out the Docker-image and prose false-positives in the bun:* grep — only bun:ffi, bun:jsc, bun:internal, bun:sqlite, bun:test are real modules at the time of this audit. Also note the rfcs/ tree is shared with the rfc-patties-ui-* family (patties-ui-parity-matrix.md); this matrix's counts and audit cover rfc-bun-* only.