Start here
There is one decision here and everything follows from it: is your problem common enough that someone already trained a model for it, or specific to your data?
- Common task, low volume, want it working today → Amazon Rekognition or a specialist API
- Content moderation specifically → Sightengine
- Text in images → Tesseract OCR, not a general vision API
- Hands, pose, face landmarks, segmentation on-device → Google MediaPipe
- Your own data, your own labels → Roboflow
- High volume, cost matters, you have the skills → run your own with OpenCV and a model
Getting this wrong is expensive both ways. Teams spend months building a detector an API would have answered in an afternoon, and other teams wire in a per-call API for something that runs millions of times a day.
Compare
| Option | Type | Licence | Cost | Score | Confidence |
|---|---|---|---|---|---|
| Sightengine | Hosted API | Proprietary | From $0.00/mo, free tier | 71.9 | 0.43 |
| Roboflow | Training platform | Proprietary | From $79/mo, 14-day trial | 57.7 | 0.56 |
| Google MediaPipe | Library | Apache-2.0 | Free | 56.6 | 0.26 |
| Imagga | Hosted API | Proprietary | From $79/mo, free tier | 54.6 | 0.11 |
| Amazon Rekognition | Hosted API | Proprietary | Usage-based, free tier | 53.7 | 0.45 |
| OpenCV | Library | Apache-2.0 | Free | 52.5 | 0.34 |
| Tesseract OCR | Library | Apache-2.0 | Free | 51.1 | 0.34 |
| Detectron2 | Library | Apache-2.0 | Free | 42.9 | 0.40 |
All four libraries are Apache-2.0 with no recorded advisories, which removes licence and security from the decision entirely and leaves it on fit.
Calling an API
Sightengine
From $0.00/month, hybrid, free tier. Score 71.9, confidence 0.43.
Highest-scoring here, and specialised: moderation, nudity and violence detection.
Pick it ifmoderation is your problem. A specialist API beats a general one on a specialist task. Don't if you need general object detection.
Amazon Rekognition
Usage-based, free tier. Score 53.7, confidence 0.45.
Labels, faces, text and moderation in one service.
Pick it ifyou are already in AWS and the task is conventional. Don't if your volume is high; work out cost per thousand calls first.
Imagga
From $79/month. Confidence 0.11.
Verdicttagging and categorisation focus. Confidence too low for us to say more; evaluate directly.
Running your own
OpenCV
Apache-2.0, free. 90,819 stars. Shipped 2026-07-19. No advisories.
The answer to alternative to opencv is usually that there isn't one for what you are doing. It is not a model, it is the library you use to manipulate images before and after a model touches them.
Pick it ifyou are doing image processing at all. You will end up using it regardless. Don't expect it to classify anything on its own.
Tesseract OCR
Apache-2.0, free. 76,472 stars. Shipped 2026-07-24. No advisories.
Pick it ifyour problem is text in images. Start here rather than a general vision API, and expect to spend time on preprocessing.
Google MediaPipe
Apache-2.0, free. 36,914 stars. Shipped 2026-07-28. No advisories.
Ready-made pipelines for hands, pose, face landmarks and segmentation, running on-device.
Pick it ifyour task is on that list. It removes per-call cost and the question of sending images to a third party at the same time.
Detectron2
Apache-2.0, free. 34,707 stars. Last release 2021-11-15.
Pick it ifyou are working from research code and know what you are doing. Don't build a new production system on a five-year-old release without checking current maintenance directly.
Training your own
Roboflow
From $79/month, hybrid, free tier, 14-day trial. 16 integrations, the most here. Confidence 0.56.
The only platform covering labelling through training to deployment.
Pick it ifyour data is specific and you want one tool for the whole path. Don't if your data cannot leave your infrastructure; then it is a labelling tool plus a training framework plus your own deployment, which is genuinely more work.
We hold Roboflow's entry price but not its enterprise figure, which is quoted. Both roboflow alternative open source and roboflow enterprise pricing are queries we see, which is the familiar pattern of people evaluating it and then checking what it costs at scale.
How we scored this
Signals are properties of the software: licence, release cadence, published advisories, integrations, pricing transparency. No reviews, no company size, no web traffic, no vendor ad spend. Facts retrieved 2026-09-11. Full method · Independence
The most important thing we could not verify is accuracy, and here that is the whole ballgame. We hold no benchmark data, no per-task precision or recall, and no comparison of model quality. A vision tool is chosen on how well it performs on your images, and we cannot tell you that. What we can tell you is what each costs, how it is licensed, whether it is maintained, and which shape of problem it is built for.
Anyone publishing an accuracy ranking across these eight is either benchmarking on a dataset that does not resemble yours or repeating vendor claims. Test on your own images.
Eight products, confidence 0.11 to 0.56, median 0.39. MediaPipe at 0.26 and OpenCV at 0.34 score below hosted APIs we measure better; that ordering reflects our coverage, not the tools. OpenCV is among the most deployed software in this field.