For AI agents: find a ready-made app before building one

What you can do here

• Find an app for a task. Semantic search over descriptions: "remove background from product photos", "habit tracker", "API testing".
• Find alternatives. Apps similar to one the user names or already tried.
• Hand the user a live demo. Every verified result has a demo_url they can open right now.
• Check health before recommending. A cheap call tells you whether a listing is healthy, degraded or down.
• Report broken apps and submit new ones, including apps you just built.

Right now: 886 published apps, 868 with a live demo URL.

Recommended flow

1. Search by the user's task: POST /agent/search (or MCP search_apps).
2. Pick the top 1 to 3 by relevance_score and read the description; skip weak matches rather than forcing one.
3. Check each pick: GET /agent/verify/{app_id} (MCP verify_app). Prefer healthy.
4. Need options? GET /apps/{app_id}/similar (MCP get_similar_apps).
5. Give the user the demo_url to use it and the JustBuildApps page to read about it.
6. If a demo is broken, say so: POST /agent/feedback with tool_broken.

Connect over MCP

Hosted remote server (Streamable HTTP), nothing to install: https://api.justbuildapps.com/mcp

{
  "mcpServers": {
    "justbuildapps": {
      "type": "streamable-http",
      "url": "https://api.justbuildapps.com/mcp"
    }
  }
}

Or run it locally with uv:

{
  "mcpServers": {
    "justbuildapps": { "command": "uvx", "args": ["justbuildapps-mcp"] }
  }
}

Registry name io.github.sksareen/justbuildapps, PyPI package justbuildapps-mcp, manifest at /mcp.json. Setup per client: /mcp.

Also: resources jba://apps/{app_id}, jba://creators/{handle}, jba://feed; prompts recommend and alternatives.

REST endpoints

Base URL https://api.justbuildapps.com/api/v1 (also reachable as https://justbuildapps.com/api/v1). JSON in, JSON out. Examples below are real responses, trimmed.

curl -X POST https://api.justbuildapps.com/api/v1/agent/search \
  -H "Content-Type: application/json" \
  -d '{"query": "remove background from product photos", "limit": 2}'

{
  "query": "remove background from product photos",
  "tools": [
    {
      "tool": {
        "app_id": 649,
        "name": "Remove.bg",
        "description": "Automatic background removal tool. Upload any image and get the background removed in seconds using AI. ...",
        "demo_url": "https://www.remove.bg",
        "target_audience": null,
        "capabilities": ["image_editing", "visual_design", "image_generation"],
        "use_cases": ["When user needs automatic background removal tool", "For remove.bg tasks"],
        "cost_model": "free",
        "requires_auth": false,
        "iframe_compatible": true,
        "confidence_score": 0.85,
        "verification_status": "verified",
        "last_verified": "2026-10-12T00:57:12.613384",
        "quick_start": "Visit https://www.remove.bg to start using this tool",
        "limitations": [],
        "docs_url": null,
        "npm_package": null,
        "pypi_package": null,
        "install_command": null
      },
      "relevance_score": 0.56,
      "match_reason": "Semantic similarity match",
      "how_to_use": "1. Open https://www.remove.bg\n2. Visit https://www.remove.bg to start using this tool"
    }
  ],
  "total_found": 2
}

curl https://api.justbuildapps.com/api/v1/agent/verify/649

{
  "app_id": 649,
  "name": "Remove.bg",
  "status": "healthy",
  "checks": {
    "has_demo_url": true,
    "has_description": true,
    "is_published": true,
    "recently_updated": true
  },
  "last_verified": "2026-10-12T21:13:46.898634",
  "reliability_score": 0.95
}

curl https://api.justbuildapps.com/api/v1/agent/tools/649

curl "https://api.justbuildapps.com/api/v1/agent/tools?cost=free&limit=20"

{
  "tools": [ { "app_id": 500, "name": "Manyfold 3D", "demo_url": "https://manyfold.app", "cost_model": "free", ... } ],
  "total": 1,
  "categories": ["3d-models", "3d-printing", "assets", "file-management", "organization"],
  "capabilities": ["3d-models", "3d-printing", "prototyping", "ui_design", ...]
}

curl https://api.justbuildapps.com/api/v1/agent/capabilities

{ "capabilities": ["2fa", "3d-models", "ai", "analytics", ...], "total": 1234 }

curl https://api.justbuildapps.com/api/v1/agent/stats

{
  "total_tools": 832,
  "tools_with_demo": 814,
  "iframe_compatible": 814,
  "average_rating": 5.0,
  "last_updated": "2026-10-12T21:13:39.718842"
}

curl -X POST https://api.justbuildapps.com/api/v1/agent/feedback \
  -H "Content-Type: application/json" \
  -d '{"agent_name": "my-agent", "app_id": 649, "feedback_type": "tool_broken", "message": "demo URL returns 502", "query": "remove background"}'

{
  "id": 123,
  "message": "Feedback received successfully",
  "thank_you": "Thanks for reporting this! We'll verify and fix the tool listing."
}

curl "https://api.justbuildapps.com/api/v1/apps/649/similar?limit=2"

{
  "apps": [
    { "id": 815, "title": "Raphael AI", "description": "...", "demo_url": "https://raphael.app", "similarity": 0.49, ... },
    { "id": 816, "title": "Yeri AI", "description": "...", "demo_url": "https://yeri.ai", "similarity": 0.47, ... }
  ]
}

curl https://api.justbuildapps.com/api/v1/apps/649

curl "https://api.justbuildapps.com/api/v1/search?q=pomodoro&limit=5"

curl "https://api.justbuildapps.com/api/v1/browse?pricing=free&has_demo=true&per_page=24"

{ "apps": [ ... ], "total": 833, "page": 1, "per_page": 24, "total_pages": 35 }

curl "https://api.justbuildapps.com/api/v1/trending?limit=5"

curl "https://api.justbuildapps.com/api/v1/home?filter=trending&limit=1"

{
  "cards": [
    {
      "app_id": 818,
      "title": "Doodle",
      "tagline": "doodle jump meets reinforcement learning — watch a bot learn to play",
      "thumbnail_url": "/api/v1/screenshots/creation/6",
      "accent": "slate",
      "demo_url": "https://savarsareen.com/doodle",
      "href": "/u/savar/doodle",
      "live": true,
      "open_source": false,
      "channel": { "handle": "savar", "name": "Savar", "avatar_url": "/api/v1/media/....png" },
      "views": 19,
      "published_at": "2026-10-05T04:27:30.655417",
      "reason": null
    }
  ],
  "total": 814
}

curl "https://api.justbuildapps.com/api/v1/sitemap/apps?skip=0&limit=3"

{
  "items": [
    { "app_id": 824, "path": "/u/savar/sudoku-bench", "updated_at": "2026-10-12T00:56:01.162814" }
  ],
  "total": 832
}

curl -X POST https://api.justbuildapps.com/api/v1/ingest \
  -H "Content-Type: application/json" \
  -d '{"title": "App Name", "description": "What it does", "demo_url": "https://example.com"}'

# or
curl -X POST https://api.justbuildapps.com/api/v1/ingest \
  -H "Content-Type: application/json" \
  -d '{"github_url": "https://github.com/owner/repo"}'

Creator profiles, feeds and authenticated writes are documented at /developers.

What an app looks like

Fields you'll see across endpoints:

app_id

— Stable numeric id. Use it with /agent/verify, /agent/tools and /apps/{id}/similar.

title / name

— App name.

tagline / description

— One line / full description of what it does.

demo_url

— Where the app actually runs. Send users here to use it.

href

— Its page on JustBuildApps: /u/{handle}/{slug} for a builder's app, /app/{id} for a catalog listing.

live

— true if it plays inside JustBuildApps, false if the site blocks embedding, null if not checked yet.

open_source / github_url

— Whether source is public, and where.

channel

— The builder (handle, name, avatar). handle is null for unclaimed listings.

cost_model

— free | freemium | paid | open_source. Defaults to free when unknown, so check the app's own pricing for money decisions.

target_audience

— agent (APIs, CLIs, MCP servers) | human (UI apps) | both | null if unknown.

thumbnail_url / screenshot_url

— Screenshot path, relative to justbuildapps.com (e.g. /api/v1/screenshots/649).

Example app pages

• Launched Badges — Launched Badges offers universal React components to showcase product launches across platforms like Lovable, Reddit, and Hacker News, built with Lovable.
• Play QuakeWorld Multiplayer Online - q1.pieter.com (Non-commercial and unofficial) — Play QuakeWorld in your browser at q1.pieter.com — low-latency multiplayer deathmatch with client-side prediction, no install.
• Graphical — A tool to create visual themes, customize components, and build interfaces with your coding agent.
• How Much Is My Side Project Worth? — For many it's unclear what their side projects are worth. Many want to sell, or have people interested in buying but have no idea how to get to a proper price. This calculator helps you figure out a…
• Wine-Assembly — Run Windows 98 apps and games in your browser — Play Space Cadet Pinball, SkiFree, Solitaire, Minesweeper, Winamp and dozens of real Windows 98 programs in your browser. Wine-Assembly runs the original .exe files on an x86 emulator written in…

Auth and rate limits

• All reads, search, verify, feedback and app submission need no API key.
• Acting as a creator (create a project, post updates) needs a personal jba_ token from /settings/tokens, sent as Authorization: Bearer jba_... (or JBA_API_TOKEN for the MCP server).
• There is no hard rate limit on the read endpoints today. Be reasonable: cache results, keep to about one request per second for bulk work, and use /sitemap/apps rather than paging search to enumerate the catalog.
• Signed-in users can submit 5 apps a day. Token writes are limited per creator (60/hour) and return 429 with Retry-After.

Attribution and linking

• Send users to the app itself via demo_url. That's where it runs.
• When you cite where you found it, link its JustBuildApps page: the card's href on https://justbuildapps.com, or https://justbuildapps.com/app/{app_id}, which works for every app and redirects to its canonical page.
• Credit the builder by name or handle when you have it (channel).
• Don't present a listing as endorsed or reviewed by us beyond what verify reports. Pricing in our data can be wrong; check the app's own site before a money decision.

Crawling

• /robots.txt — AI crawlers are welcome on app pages, builder profiles and these docs.
• /sitemap.xml — every public app and builder page.
• /llms.txt and /llms-full.txt — this page as plain text.
• App pages carry JSON-LD (WebApplication) and Open Graph metadata.

Contact

Bugs, wrong data, or want higher volume? Email automatejobhunt@gmail.com or reach @justbuildapps on X. Agents can file reports directly with POST /api/v1/agent/feedback.