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AI Image & Video API Guides
Hands-on model tests, production tutorials, prompt techniques, and current API pricing for generative media teams.
hiapi 'model not available' / 'model not found' errors: causes and fixes
A rejected /v1/tasks request can come from an unavailable model name, an invalid input field, a route mismatch, or a separate authentication problem. HiAPI model names do not share one naming pattern; copy the exact fixed value from the current model documentation. GPT Image 2 text-to-image requests use gpt-image-2/text-to-image, including the modality suffix. A minimal POST /v1/tasks request confirms whether the model and input shape are accepted before you add polling or callbacks. Treat 400 request validation separately from 401 invalid-key and 403 permission errors.
Why your hiapi task callback isn't firing, and how to fix it
If your task reached a terminal status but your endpoint never got a POST, the problem is almost always in the delivery path — not in hiapi. The big 5 causes: unreachable URL, TLS chain issues, your handler returning slow/non-2xx, missing Webhook Sign Key vs. strict verification, and forgetting to include the callback object at submission. Test the callback URL from outside your network first; it must accept an HTTPS POST and return 2xx within the timeout. Generate a Webhook Sign Key under /en/dashboard/settings and align your verification — don't sign with one key and verify with another. Always pair callbacks with polling GET /v1/tasks/{taskId} as the source of truth; the callback is a notification, the GET is the contract.
OpenAI API Proxy in Python: Build One, Then Point It at Every Model
A 50-line FastAPI proxy that swaps keys, rate-limits tenants and streams responses. HiAPI's /v1/chat/completions and /v1/responses accept the OpenAI request shape, so the official SDK works with base_url set. Images and video run on async /v1/tasks and shouldn't go through a synchronous proxy.
How to Fix HiAPI Rate Limit (429) Errors
HiAPI returns HTTP 429 when a single API key sends too many concurrent or back-to-back requests to /v1/tasks or the polling endpoint. The most common trigger is fan-out: many parallel task creations from one key, or a tight polling loop on GET /v1/tasks/{taskId}. Fix it by adding exponential backoff (1s/2s/4s, cap 30s), capping client concurrency, switching from polling to callback.url, and slowing polling cadence to 2-5s with jitter. Check current usage at the HiAPI dashboard to confirm whether you are hitting account-level concurrency limits or running out of plan headroom. Use a Nano-Banana curl request to verify your key and network path once the retry layer is in place.
Cheapest Image and Video Generation APIs: Live Prices on HiAPI
Cheapest images: FLUX.2 Klein 4B from $0.00036, FLUX.1 Schnell $0.005, Z-Image $0.008. Cheapest video: Grok Imagine at $0.015 per second at 480p. Real cost is price per image times tries to an acceptable result.
Z-Image API: $0.008 per Image, Real Outputs and Code
The model id is z-image and it costs $0.008 per image. The request is just prompt and aspect_ratio. Four product shots with short English text all came out spelled correctly.
Image to Video API Workflow: Runway, Wan 2.7, Vidu, and Production API Patterns
Image-to-video is the right call when the opening frame is fixed — a product render, an approved key visual, a character sheet — and you need motion that respects it instead of a freshly hallucinated scene. {"The single biggest quality lever is the source image": "its resolution and aspect ratio cap the output, and a clean, well-framed subject gives the model far less room to drift."} First-frame control pins where the clip starts; adding a last frame pins where it ends, which is the most reliable way to kill end-of-clip motion drift. Prompt the change, not the scene. With i2v the model can already see the subject, so the prompt's job is the motion and the camera, not a description of what's in the frame. On HiAPI the callable workflow runs on Seedance 2.0 and Wan 2.7 image-to-video through one async task API — create, poll or get a callback, download — billed per second, so resolution and duration are your cost.
API Key Is Invalid? Why "API Key Data Are Invalid" Happens and How to Fix It
Most invalid-key errors are not bad keys — they're whitespace, a wrong env var, a stale key, or a key sent to the wrong base URL. Read the error body, not just the status: it names the real cause and usually carries a request_id you quote to support. On HiAPI an auth failure is HTTP 401 with code permission_denied and type hiapi_error — not error_key_does_not_exist or invalid_api_key (those are other ecosystems' strings). claude code invalid api key is almost always the Anthropic key or a base-URL override — fix that, not HiAPI. Run the 8-step checklist below to validate any key with one minimal API call before you debug your app.
Free AI Image Generation API, No Key Required: We Tested 4 in 2026
Pollinations' old URL returned one watermarked image, then HTTP 402 asking $0.01 in USDC per image. AI Horde's anonymous key 0000000000 works at up to 580×580; one of four harmless prompts was blocked as NSFW. With a key, GPT Image 2 on HiAPI costs $0.007 per image and followed the same prompts far more closely.
Free Text-to-Video API With No Key? What Exists and the Cheapest Real Option
Any video API you can call from code needs a key; "free" usually means a web tool or a small sign-up credit. HiAPI gives 200 credits ($0.10) at sign-up, enough for one 6-second 480p Grok Imagine clip. Tune prompts on a low-cost model, then render the final cut on a stronger one.
Build with the models you just read about.
Compare image, video, and audio models, then use the same API workflow in production.