Tubeofile API

Public read-only JSON API for vacuum tube data. All endpoints are unauthenticated, CORS-open (Access-Control-Allow-Origin: *), and cacheable. Intended for AI agents, third-party apps, and research tools.

Overview

Tubeofile exposes structured tube data via a small set of REST-style endpoints. The typical workflow for an agent or script is:

Fetch /api/tubes/index once to discover all available tube type numbers.
Fetch /api/tubes/{type_number} for full data on specific tubes.
For substitution/rolling questions, fetch the static JSON at /rolls/{type_number}-roll.json.

Type numbers containing / or , (e.g. 5A/152M, RL2,4P6) must be URL-encoded.

GET /api/tubes/index

Lightweight listing of every tube in the database. Start here.

curl https://tubeofile.com/api/tubes/index

Response:

{ "count": 517, "generated_at": "2026-04-07T12:00:00.000Z", "tubes": [ { "type_number": "12AX7", "manufacturer": "RCA", "tube_type_key": "small_signal_triode", "tube_type": "Small-signal triode (dual)", "base": "Noval", "is_directly_heated": false, "url": "https://tubeofile.com/tubes/12AX7", "api_url": "https://tubeofile.com/api/tubes/12AX7" } ] }

GET /api/tubes/{type_number}

Full structured data for a single tube: specs, pinout, equivalents, similar tubes, and source references. Returns 404 if no matching tube exists.

curl https://tubeofile.com/api/tubes/EL34 curl https://tubeofile.com/api/tubes/5A%2F152M # URL-encoded slash

Response shape:

{ "type_number": "EL34", "canonical_url": "https://tubeofile.com/tubes/EL34", "manufacturer": "Mullard", "tube_type_key": "power_pentode", "tube_type_display_name": "Power pentode", "base_name": "Octal", "description": "...", "is_directly_heated": false, "notes": ["..."], "references": ["https://..."], "source_urls": { "r_type": "https://www.r-type.org/...", "tdsl": "https://tdsl.duncanamps.com/...", "radiomuseum": "https://..." }, "raw_equivalents": ["6CA7", "E34L", "EL34B"], "equivalents": [ { "type_number": "6CA7", "equivalence_type": "direct", "notes": null } ], "similar": [ { "type_number": "KT88", "reason": "...", "has_detail_page": true } ], "pins": [ { "pin_number": "1", "function": "Suppressor grid", "function_code": "g3", "notes": null } ], "specs": [ { "key": "Vh", "display_name": "Heater voltage", "value": "6.3", "numeric_value": 6.3, "unit": "V", "param_group": "heater" } ], "sections": [], "synced_at": "2026-04-04T00:00:00.000Z" }

GET /api/tubes

Full-text search and filtering. Returns an array of summary tube objects.

curl "https://tubeofile.com/api/tubes?q=octal+pentode" curl "https://tubeofile.com/api/tubes?type=power_pentode&limit=20" curl "https://tubeofile.com/api/tubes?vh=6.3&dht=0" curl "https://tubeofile.com/api/tubes?q=12A&autocomplete=1"

Query parameters:

q — full-text search query (searches type_number, description, notes, manufacturer)
autocomplete=1 — prefix autocomplete mode (requires q)
type — filter by tube_type_key (e.g. power_triode, small_signal_triode, power_pentode, rectifier)
base_id — filter by tube base UUID (use /api/tubes/index to discover base names)
vh — filter by heater voltage (e.g. 2.5, 6.3, 12.6, other)
dht — 1 for directly heated only, 0 for indirectly heated only
limit — max results (default 50, max 200)
offset — pagination offset (default 0)

Rolling reports

Pre-generated tube rolling (substitution) analyses are served as static JSON at /rolls/{type_number}-roll.json. Not every tube has a rolling report — only targets that were specifically analyzed.

curl https://tubeofile.com/rolls/EL34-roll.json curl https://tubeofile.com/rolls/2A3-roll.json

Rolling report structure is documented in the rolling FAQ.

Caching & limits

All public endpoints send Access-Control-Allow-Origin: * so browser-side clients can read them.
Responses include Cache-Control headers with sensible defaults (minutes for search, up to an hour for the index and per-tube data).
There are no hard rate limits today, but please cache responses and do not poll the index endpoint more often than hourly — the underlying data changes infrequently.
If you need bulk data regularly, consider cloning the tube-data repo — all canonical tube JSONs live there.

For AI agents

Tubeofile publishes /llms.txt at the site root following the emerging convention for AI-agent discoverability. It contains the same overview as this page in a Markdown format optimized for LLM consumption.

Every tube HTML page also embeds schema.org Product JSON-LD with a mainEntityOfPage pointer to the corresponding API URL, so agents that land on an HTML page via search can hop directly to structured data.