OpenRouter universal gateway in Nebula — one node (openrouter-universal) that reaches hundreds of models (GPT, Claude, Gemini, Llama, DeepSeek, FLUX, Recraft, and more) through OpenRouter's chat-completions API. Capabilities exposed in Nebula: streaming text/chat/reasoning/coding, vision (image-in → text-out), and image generation (text → image) — the model you pick decides which. Activate when the user configures the `openrouter-universal` node (display name "OpenRouter"), picks/searches an OpenRouter model in the Inspector, or asks about OpenRouter in Nebula. Sourced from the official OpenRouter docs (openrouter.ai/docs) and the Nebula audit guide docs/api-guides/openrouter.md on 2026-06-04 — every node id, port, param, header, and capability boundary here is cross-checked against backend/handlers/openrouter.py, backend/routes/openrouter_proxy.py, and backend/data/node_definitions.json.
Installation
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OpenRouter universal gateway in Nebula — one node (openrouter-universal) that reaches hundreds of models (GPT, Claude, Gemini, Llama, DeepSeek, FLUX, Recraft, and more) through OpenRouter's chat-completions API. Capabilities exposed in Nebula: streaming text/chat/reasoning/coding, vision (image-in → text-out), and image generation (text → image) — the model you pick decides which. Activate when the user configures the `openrouter-universal` node (display name "OpenRouter"), picks/searches an OpenRouter model in the Inspector, or asks about OpenRouter in Nebula. Sourced from the official OpenRouter docs (openrouter.ai/docs) and the Nebula audit guide docs/api-guides/openrouter.md on 2026-06-04 — every node id, port, param, header, and capability boundary here is cross-checked against backend/handlers/openrouter.py, backend/routes/openrouter_proxy.py, and backend/data/node_definitions.json.
OpenRouter Skill
When to use
User drags or configures the OpenRouter node (openrouter-universal) onto the canvas.
User picks or searches a model in the Inspector's OpenRouter model dropdown.
User wants chat / writing / summarization / code / reasoning / Q&A from any text model (GPT, Claude, Gemini, Llama, DeepSeek, Mistral, Qwen…) without leaving Nebula.
User wants to ask a question about an image (vision: image-in → text-out).
User wants to generate an image from a prompt via an image-output model on OpenRouter (e.g. Gemini Flash Image, FLUX, Recraft).
User asks about OpenRouter auth, the model list, or which model to pick for a job.
It's one node that reconfigures itself based on the chosen model. There is no separate "OpenRouter image" or "OpenRouter vision" node — same openrouter-universal, different model.
Universal rules
Auth — OPENROUTER_API_KEY. Sent as Authorization: Bearer <OPENROUTER_API_KEY>. The key (from https://openrouter.ai/keys, format sk-or-...) goes in Nebula Settings → OpenRouter or .env as OPENROUTER_API_KEY=sk-or-.... It is required both to run the node and to load the model dropdown — until it's set, the model picker can't populate (the /api/openrouter/models proxy returns 400 OPENROUTER_API_KEY not configured).
Attribution headers (sent by the handler, do not re-add). Every request also carries HTTP-Referer: http://localhost:5173 and X-OpenRouter-Title: Nebula Nodes. ⚠️ Nebula uses X-OpenRouter-Title, not the legacy X-Title header that some OpenRouter docs show — the handler tests explicitly assert X-Title is not present. Don't tell the user to set X-Title.
Base URL:https://openrouter.ai/api/v1/chat/completions (chat-completions endpoint for everything — text, vision, and image generation all go through this one URL). Model list proxy: GET /api/openrouter/models (Nebula backend → OpenRouter /api/v1/models, cached 5 min).
Execution pattern depends on output type (no async polling either way):
Text / vision → streaming (SSE).executionPattern: "stream". Sends stream: true; tokens stream into the text output via delta_path = choices.0.delta.content; the stream ends on [DONE]. Timeout 30s.
Image output → single synchronous POST (not streamed). When the picked model has image in its output modalities, the handler sends modalities: ["text","image"] and does one blocking request (120s timeout), then reads the picture from choices[0].message.images[].
Status / error codes.200 success. On the image path a non-200 raises OpenRouter API error <code>: <body>. Common: 400 bad request / no model / key not configured (model proxy), 401 bad or missing key, 402 insufficient credits, 429 rate-limited, 5xx upstream/provider error. Surface the body — OpenRouter returns useful messages.
Input-URI rules (vision images port). The handler accepts, per image: an http(s):// URL (passed through as image_url), a data: URI (passed through), or a local file path (the handler base64-encodes it and builds a data URI; recognized suffixes png/jpg/jpeg/webp, anything else is sent as image/png). Upstream image-generation nodes wired into images resolve to local paths, so they "just work."
Key gotchas.
model is required and drives everything. No default model (default is ""). If unset, the run fails with "No model selected — choose a model from the Inspector panel."
Ports are dynamic, set when you pick the model — not configured by hand. Picking a model with imageinput adds the images input port; picking one with imageoutput adds the image output port and flips the internal _output_image flag. Changing the model drops edges connected to ports that no longer exist.
temperature and max_tokens are text-only. The image path never sends them; they're ignored for image generation. (The handler does still attach them to the request body if present, but image models disregard sampling params.)
Vision needs both inputs.messages (your question) is always required; images is the picture. A vision model with no images wired just behaves like a text model.
JSON mode works (response_format=JSON, model-dependent); but no tools, no strict json_schema/grammar, no audio/PDF/video, no provider routing, no image_config, no web search. See Capability boundaries — never promise these.
Pick the right node
There is exactly one OpenRouter node. The model dropdown is what varies.
Node (in app)
Node ID
Endpoint / model
Key params
Use it for
OpenRouter
openrouter-universal
POST https://openrouter.ai/api/v1/chat/completions — model chosen live from /api/openrouter/models (OpenRouter's full catalog)
model (required, string; from the live searchable list), temperature (float 0–2, default 1, text only), max_tokens (int 1–200000, default 4096, text only), response_format (Text / JSON, text only — JSON mode, model-dependent), prompt_caching (boolean, default off — opt-in cache_control for Anthropic-family models)
One node for the whole OpenRouter catalog. Text chat/reasoning/coding with any text model · vision Q&A (image-in → text-out) with a vision model · image generation (text → image) with an image-output model. The chosen model decides which.
The model list is live and per-account (backend proxies OpenRouter's /api/v1/models, slimmed to id / name / input_modalities / output_modalities / context_length / pricing, cached 5 min). You are not limited to a hardcoded set — use the Inspector search box to filter. To do a given job, pick a model whose modalities match it: text-out for chat, image in input_modalities for vision, image in output_modalities to generate pictures.
The OpenRouter model id (e.g. openai/gpt-4o, anthropic/Claude-3.5-sonnet, google/gemini-2.5-flash-image). Chosen from the live list; selecting it reconfigures ports and sets _output_image automatically.
Temperature
temperature
float
0 – 2, step 0.1, default 1
text/vision only
Higher = more random. Lower (e.g. 0.2–0.4) = more focused/deterministic. Ignored by image generation.
Max Tokens
max_tokens
integer
1 – 200000, default 4096
text/vision only
Upper bound on generated tokens. Ignored by image generation.
Response Format
response_format
enum
Text / JSON, default Text
text only
JSON mode (added 2026-06-05). When set to JSON the handler forwards response_format: {"type":"json_object"}, so the reply is valid JSON. Model-dependent — the chosen model must support JSON output. Live-verified against the API.
Prompt Caching
prompt_caching
boolean
default off
text/vision
Opt-in prompt caching (added 2026-06-05). When on, the handler attaches cache_control: {type: ephemeral} to the last user content block. OpenRouter passes it through to Anthropic-family models (cache read ~90% cheaper on a re-run within ~5 min); other providers ignore it, and OpenAI models cache automatically so the toggle is a no-op for them. Off by default because a never-reused large prefix pays a small cache-write premium.
Internal / not user-set:_output_image (boolean) — written by the frontend when you pick a model with image output; it routes the run to the image path. Don't expose or hand-edit it.
Not exposed (the API supports them; the node does not send them):top_p, top_k, seed, stop, frequency_penalty, presence_penalty, repetition_penalty, min_p, logit_bias, tools / tool_choice, strict json_schema / grammar (basic json_object JSON mode is now exposed via response_format — see above), reasoning / reasoning_effort, provider routing, image_config (aspect ratio / size / style / strength), web-search plugins. (cache_controlis now exposed via the opt-in prompt_caching toggle — see above.) See Capability boundaries.
Recipes
Recipe 1 — Ask a model a question (text / chat)
Add a Text input node with your prompt (e.g. "Explain quantum entanglement in one paragraph").
Add an OpenRouter node (openrouter-universal); in the Inspector pick a text model.
Wire the Text node → messages. Optionally lower temperature (e.g. 0.3) for a focused answer; raise max_tokens for longer output.
Run. The reply streams into the text output, which chains into any node that accepts Text.
Add an OpenRouter node and pick a vision model (one that lists image in its input modalities). An Images input port appears.
Wire an image source — an upstream image-generation node's image output, or an image file — into images, and a Text node with your question ("What's in this photo?", "Read this receipt", "What's wrong with this UI?") into messages.
Run. The description streams out of text.
Recipe 3 — Generate an image (text → image)
Add an OpenRouter node and pick an image-output model (e.g. a Gemini Flash Image, FLUX, or Recraft variant — one that lists image in its output modalities). An Image output port appears and the node switches to image mode.
Wire a Text node with your prompt ("a neon-lit crab on a beach at dusk, cinematic") into messages. (temperature/max_tokens don't apply here.)
Run. The handler does one POST, pulls the picture from choices[0].message.images[], saves it as a PNG in the run directory, and emits it on image — ready to feed an upscaler, a video node, or a save node.
In the nebula_nodes context
Node id:openrouter-universal (display "OpenRouter", category: universal, apiProvider: openrouter). Lives in the Universal category of the palette alongside Replicate / Nous Portal.
Model list proxy:backend/routes/openrouter_proxy.py → GET /api/openrouter/models (5-min cache via services/model_cache.py). Frontend fetches it in frontend/src/lib/api.ts.
Dynamic-port wiring:frontend/src/store/graphStore.ts → configureOpenRouterModel(nodeId, modelId, model). It reads input_modalities / output_modalities and rebuilds ports; sets params.model = modelId and params._output_image = output_modalities.includes('image').
Ports:
Input — messages (Text, required) always present; images (Image, multiple, optional) added only for models with image input.
Output — text (Text) present for text-output models; image (Image) added for image-output models. The base node ships with just messages in / text out; the rest appear after a model is chosen.
Chaining rules:
text output → any Text input (another OpenRouter node, a TTS node, a save/text node, an image-gen node's prompt, etc.).
image output → any Image input (upscaler, video/image-edit node, vision node's images, save node).
Into images: accepts http(s) URLs, data URIs, or local file paths (handler base64-encodes local files). Multiple images allowed.
Switching models mid-graph drops edges on ports that disappear — rewire after changing the model.
How outputs render:text streams token-by-token into the node as it generates. image is saved as a PNG in the run directory (save_base64_image) and surfaced on the Image port; it renders in the canvas image preview like any other Image output.
Capability boundaries — what OpenRouter's API can do that Nebula does NOT expose
Do not promise these through the node. They're real OpenRouter API features, just not surfaced in Nebula (≈30% of the API surface is wired: text chat, streaming, vision input, basic image gen, and the model list). If a user needs one, say it's an API feature not yet exposed in Nebula.
Capability
API
Nebula
Note
Tool / function calling (tools, tool_choice, parallel_tool_calls)
Yes
No
The node never sends tools. No function calling.
Structured outputs — json_object JSON mode
Yes
Yes
Wired 2026-06-05, live-verified. response_format=JSON → {"type":"json_object"} for text models (model-dependent).
Structured outputs — strict json_schema / grammar
Yes
No
Can't request JSON-schema-constrained or grammar-constrained output; only json_object JSON mode.
Reasoning controls (reasoning, reasoning_effort)
Yes
No
No reasoning effort / summary controls.
Extra sampling params (top_p, top_k, seed, stop, penalties, min_p, logit_bias)
Can't pin/exclude providers, set price/latency prefs, or define fallback chains.
Web Search server tool (openrouter:web_search, :online, plugins)
Yes
No
No web-grounded answers.
Prompt caching (cache_control)
Yes
Yes (opt-in)
The prompt_caching toggle (default off, added 2026-06-05) sets an ephemeral cache_control breakpoint on the last content block. Passed through to Anthropic-family models (~90%-cheaper cache reads on re-runs); other providers ignore it; OpenAI caches automatically.
