A small editor for the files in your storage.
Mosaic opens YAML, JSON, and Markdown straight from any S3-compatible bucket — Amazon S3, Backblaze, Wasabi, Cloudflare R2, or NimbusNexus. Edit them, preview them, version them, save them, ship them — without leaving the browser, and without ever downloading a thing.
Launching Mosaic
Sven Larsson · May 03For years, editing a config file meant downloading, opening, editing, re-uploading — a small ritual repeated thousands of times a week.
Mosaic ends the ritual. The file lives in storage. The editor opens it there.
What it can do today
- →Edit YAML, JSON, and Markdown
- →Live preview for Markdown
- →Schema validation
- →Revisions on every save
- →Approvals & publish flow
Bring your bucket. Mosaic edits it.
Connect any S3-compatible storage with an API key — your credentials stay encrypted, your data stays where it is. Same Mosaic experience, your provider.
API keys are encrypted at rest with per-account keys; we never log raw credentials. Rotate or revoke any time.
Use NimbusNexus Storage? Mosaic is free. Forever.
No seat caps. No file caps. Works on every container, on every plan from Starter up.
- ✓Unlimited seats
- ✓Unlimited files
- ✓All file formats
- ✓Approvals + revisions
- ✓API + CLI access
Built for the small daily edits that nobody talks about.
Configs, manifests, content, runbooks. The files you edit twenty times a day and three times at 2am.
Config & manifest editing
Tweak a production.yaml from anywhere with a browser. Schema validation catches typos before save. Every change is a revision.
Article & blog drafting
Write Markdown with live preview. Save drafts in a public container, hit publish, watch them appear on your site. With approvals.
Incident runbooks
Keep runbooks in storage where the team can find them. Edit inline during the post-mortem. Roll back if someone deletes the wrong section.
Edit the file. Get a nod. Then ship.
For files that matter — articles, public configs, terms — Mosaic adds a lightweight approval gate. Define a rule, request a review, get a checkmark, hit publish.
- 01Path-based rulesarticles/**/*.md needs 1 editor. configs/prod/* needs 2 SREs. Match your workflow.
- 02One-click reviewReviewers see the diff inline, comment line-by-line, and approve or request changes.
- 03Block bad publishesFiles without the right approvals can't be published. CI sees it; humans see it.
- 04Full audit trailWho approved what, when, on which version. Exported with the rest of revision history.
articles/**/*.md requires 2 approvals from @editors.
Small things, done right.
Syntax highlighting
YAML, JSON, Markdown, TOML and 30+ other languages. Tasteful by default.
Three layouts
Source-only, preview-only, split. Toggle with one keystroke. Persists per-file.
Schema validation
Bring your own JSON Schema. Mosaic underlines errors and blocks invalid saves.
Publish in place
One click flips a file from private draft to public URL. Cache headers set right.
Folder + file ops
Create, rename, move, delete. Drag to upload. Multi-select with shift-click.
Approvals
Path-based rules. Inline diff review. Block-on-required. Audit-ready.
Revisions
Every save is a checkpoint. Diff any two. Restore any one. No undo limits.
Keyboard-first
A small set of shortcuts. ⌘ on Mac, Ctrl on the rest. Command palette for the rest.
What we're building.
- Markdown live previewSide-by-side or stacked. With YAML frontmatter.
- YAML / JSON schema validationBring your own schema, errors inline.
- Revisions on every saveDiff, restore, attribution.
- Folder + file CRUDIncluding drag-to-upload.
- Approval gatesPath rules + reviewer roster + inline diff.
- Multi-target publishPrimary, CDN mirror, RSS, translations.
- Command paletteAll actions, fuzzy file search, recent.
- Mobile read + light editsiPad-good. Phone is read-first.
- Real-time co-editingTwo cursors, presence, follow-cursor.
- Comments + suggestionsThreaded comments on any line.
- Translation companionSide-by-side i18n with diff against source.
- Workflow templatesPre-baked rules for blogs, configs, runbooks.
- AI suggestionsInline rephrase + schema autofix. Opt-in.
- PluginsCustom validators, custom previews, custom commands.
- Local syncEdit offline, sync on reconnect. CLI bridge.
- Audit + compliance packSOC2 evidence, DLP hooks, retention rules.
→ Roadmap is directional, not a commitment. Vote / suggest →
Edit the file.
Save the file. That's it.
Mosaic works with the cloud storage you already have — Amazon S3, Backblaze, Wasabi, Cloudflare R2, or NimbusNexus. Connect a bucket, double-click a file, you’re in.