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Introduction

Nanonets-OCR-s is an open-source, 3-parameter vision-language model that turns scanned pages and PDFs directly into richly structured Markdown instead of flat text. It preserves tables as HTML, renders equations in LaTeX, tags check-boxes with ☐/☑, wraps page numbers and watermarks in explicit tags, and even inserts image captions or auto-generated descriptions inside <img> elements—producing outputs that are ready for downstream LLM or RAG pipelines. Under the hood, Nanonets-OCR-s is fine-tuned from the Qwen 2.5-VL-3B-Instruct backbone, inheriting that model’s strong multimodal reasoning and layout-aware capabilities. This choice gives the OCR system a compact size that still fits on a single consumer GPU while reaching state-of-the-art accuracy on complex documents. Community posts and the official announcement highlight that the entire 3 B stack is released under the Apache-2.0 licence, making it free to self-host, fine-tune or embed in commercial workflows.

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Defining Dependencies

We are using the transformers to serve the model on a single A100 (80GB).

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Constructing the GitHub/GitLab Template

Now quickly construct the GitHub/GitLab template, this process is mandatory and make sure you don’t add any file named model.py. 
nanonets-ocr-s/
├── app.py
├── inferless-runtime-config.yaml
└── inferless.yaml
You can also add other files to this directory.

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Create the Input Schema with Pydantic

Using the inferless Python client and Pydantic, you can define structured schemas directly in your code for input and output, eliminating the need for external file.

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Input Schema

When defining an input schema with Pydantic, you need to annotate your class attributes with the appropriate types, such as str, float, int, bool etc. These type annotations specifys what type of data each field should contain. The default value serves as the example input for testing with the infer function. 
@inferless.request
class RequestObjects(BaseModel):
    image_url: str = Field(default="https://github.com/NanoNets/docext/raw/main/assets/invoice_test.jpeg")
    prompt: str = Field(default="""Extract the text from the above document as if you were reading it naturally. Return the tables in html format. Return the equations in LaTeX representation. If there is an image in the document and image caption is not present, add a small description of the image inside the <img></img> tag; otherwise, add the image caption inside <img></img>. Watermarks should be wrapped in brackets. Ex: <watermark>OFFICIAL COPY</watermark>. Page numbers should be wrapped in brackets. Ex: <page_number>14</page_number> or <page_number>9/22</page_number>. Prefer using ☐ and ☑ for check boxes.""")
    temperature: Optional[float] = 0.7
    do_sample: Optional[bool] = False
    max_new_tokens: Optional[int] = 15000

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Output Schema

The @inferless.response decorator helps you define structured output schemas. 
@inferless.response
class ResponseObjects(BaseModel):
    extracted_text: str = Field(default="")

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Usage in the infer Function

Once you have annotated the objects you can expect the infer function to receive RequestObjects as input, and returns a ResponseObjects instance as output, ensuring the results adhere to a defined structure. 
class InferlessPythonModel:
    def infer(self, request: RequestObjects) -> ResponseObjects:
        
        return ResponseObject(**return_result)

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Create the class for inference

In the app.py we will define the class and import all the required functions
  1. def initialize: In this function, you will initialize your model and define any variable that you want to use during inference.
  2. def infer: This function gets called for every request that you send. Here you can define all the steps that are required for the inference.
  3. def finalize: This function cleans up all the allocated memory. 
import os, io, requests
from PIL import Image
import torch
from typing import Optional
from transformers import (
    AutoTokenizer,
    AutoProcessor,
    AutoModelForImageTextToText,
)
import inferless
from pydantic import BaseModel, Field

@inferless.request
class RequestObjects(BaseModel):
    image_url: str = Field(default="https://github.com/NanoNets/docext/raw/main/assets/invoice_test.jpeg")
    prompt: str = Field(default="""Extract the text from the above document as if you were reading it naturally. Return the tables in html format. Return the equations in LaTeX representation. If there is an image in the document and image caption is not present, add a small description of the image inside the <img></img> tag; otherwise, add the image caption inside <img></img>. Watermarks should be wrapped in brackets. Ex: <watermark>OFFICIAL COPY</watermark>. Page numbers should be wrapped in brackets. Ex: <page_number>14</page_number> or <page_number>9/22</page_number>. Prefer using ☐ and ☑ for check boxes.""")
    temperature: Optional[float] = 0.7
    do_sample: Optional[bool] = False
    max_new_tokens: Optional[int] = 15000

@inferless.response
class ResponseObjects(BaseModel):
    extracted_text: str = Field(default="")

class InferlessPythonModel:
    def initialize(self):
        model_id = "nanonets/Nanonets-OCR-s"
        self.model = AutoModelForImageTextToText.from_pretrained(model_id,torch_dtype="auto",device_map="cuda",).eval()
        self.tokenizer  = AutoTokenizer.from_pretrained(model_id)
        self.processor  = AutoProcessor.from_pretrained(model_id)

    def infer(self, request: RequestObjects) -> ResponseObjects:
        image = self._fetch_image(request.image_url)
        messages = [
            {"role": "system", "content": "You are a helpful assistant."},
            {
                "role": "user",
                "content": [
                    {"type": "image", "image": image},
                    {"type": "text",  "text": request.prompt},
                ],
            },
        ]

        text_inputs = self.processor.apply_chat_template(messages, tokenize=False, add_generation_prompt=True)
        inputs = self.processor(text=[text_inputs], images=[image], padding=True, return_tensors="pt").to(self.model.device)
      
        with torch.inference_mode():
            out_ids  = self.model.generate(**inputs, max_new_tokens=request.max_new_tokens, do_sample=request.do_sample)
            gen_ids  = out_ids[:, inputs["input_ids"].shape[-1] :]
            decoded  = self.processor.batch_decode(gen_ids, skip_special_tokens=True, clean_up_tokenization_spaces=True)[0]

        return ResponseObjects(extracted_text=decoded)

    def finalize(self):
        self.model = self.processor = self.tokenizer = None

    @staticmethod
    def _fetch_image(url: str) -> Image.Image:
        resp = requests.get(url, timeout=300)
        resp.raise_for_status()
        return Image.open(io.BytesIO(resp.content)).convert("RGB")

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Creating the Custom Runtime

This is a mandatory step where we allow the users to upload their custom runtime through inferless-runtime-config.yaml. 
build:
  cuda_version: "12.1.1"
  python_packages:
    - accelerate==1.8.0
    - transformers==4.52.4
    - inferless==0.2.15
    - pydantic==2.11.7
    - pillow==11.2.1
    - torch==2.6.0
    - torchvision==0.21.0

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Test your model with Remote Run

You can use the inferless remote-run(installation guide here) command to test your model or any custom Python script in a remote GPU environment directly from your local machine. Make sure that you use Python3.10 for seamless experience.

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Step 1: Add the Decorators and local entry point

To enable Remote Run, simply do the following:
  1. Import the inferless library and initialize Cls(gpu="A10"). The available GPU options are T4, A10 and A100.
  2. Decorated the initialize and infer functions with @app.load and @app.infer respectively.
  3. Create the Local Entry Point by decorating a function (for example, my_local_entry) with @inferless.local_entry_point. Within this function, instantiate your model class, convert any incoming parameters into a RequestObjects object, and invoke the model’s infer method.
import os, io, requests
from PIL import Image
import torch
from typing import Optional
from transformers import (
    AutoTokenizer,
    AutoProcessor,
    AutoModelForImageTextToText,
)
import inferless
from pydantic import BaseModel, Field


app = inferless.Cls(gpu="A10")

@inferless.request
class RequestObjects(BaseModel):
    image_url: str = Field(default="https://github.com/NanoNets/docext/raw/main/assets/invoice_test.jpeg")
    prompt: str = Field(default="""Extract the text from the above document as if you were reading it naturally. Return the tables in html format. Return the equations in LaTeX representation. If there is an image in the document and image caption is not present, add a small description of the image inside the <img></img> tag; otherwise, add the image caption inside <img></img>. Watermarks should be wrapped in brackets. Ex: <watermark>OFFICIAL COPY</watermark>. Page numbers should be wrapped in brackets. Ex: <page_number>14</page_number> or <page_number>9/22</page_number>. Prefer using ☐ and ☑ for check boxes.""")
    temperature: Optional[float] = 0.7
    do_sample: Optional[bool] = False
    max_new_tokens: Optional[int] = 15000

@inferless.response
class ResponseObjects(BaseModel):
    extracted_text: str = Field(default="")

class InferlessPythonModel:
    @app.load
    def initialize(self):
        model_id = "nanonets/Nanonets-OCR-s"
        self.model = AutoModelForImageTextToText.from_pretrained(model_id,torch_dtype="auto",device_map="cuda",).eval()
        self.tokenizer  = AutoTokenizer.from_pretrained(model_id)
        self.processor  = AutoProcessor.from_pretrained(model_id)

    @app.infer
    def infer(self, request: RequestObjects) -> ResponseObjects:
        image = self._fetch_image(request.image_url)
        messages = [
            {"role": "system", "content": "You are a helpful assistant."},
            {
                "role": "user",
                "content": [
                    {"type": "image", "image": image},
                    {"type": "text",  "text": request.prompt},
                ],
            },
        ]

        text_inputs = self.processor.apply_chat_template(messages, tokenize=False, add_generation_prompt=True)
        inputs = self.processor(text=[text_inputs], images=[image], padding=True, return_tensors="pt").to(self.model.device)
      
        with torch.inference_mode():
            out_ids  = self.model.generate(**inputs, max_new_tokens=request.max_new_tokens, do_sample=request.do_sample)
            gen_ids  = out_ids[:, inputs["input_ids"].shape[-1] :]
            decoded  = self.processor.batch_decode(gen_ids, skip_special_tokens=True, clean_up_tokenization_spaces=True)[0]

        return ResponseObjects(extracted_text=decoded)

    def finalize(self):
        self.model = self.processor = self.tokenizer = None

    @staticmethod
    def _fetch_image(url: str) -> Image.Image:
        resp = requests.get(url, timeout=300)
        resp.raise_for_status()
        return Image.open(io.BytesIO(resp.content)).convert("RGB")

@inferless.local_entry_point
def my_local_entry(dynamic_params):
    request_objects = RequestObjects(**dynamic_params)
    model_instance = InferlessPythonModel()

    return model_instance.infer(request_objects)

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Step 2: Run with Remote GPU

From your local terminal, navigate to the folder containing your app.py and your inferless-runtime-config.yaml and run: 
 inferless remote-run app.py -c inferless-runtime-config.yaml --image_url "https://github.com/NanoNets/docext/raw/main/assets/invoice_test.jpeg" --prompt """Extract the text from the above document as if you were reading it naturally. Return the tables in html format. Return the equations in LaTeX representation. If there is an image in the document and image caption is not present, add a small description of the image inside the <img></img> tag; otherwise, add the image caption inside <img></img>. Watermarks should be wrapped in brackets. Ex: <watermark>OFFICIAL COPY</watermark>. Page numbers should be wrapped in brackets. Ex: <page_number>14</page_number> or <page_number>9/22</page_number>. Prefer using ☐ and ☑ for check boxes."""
You can pass the other input parameters in the same way (e.g., --confidence_threshold, etc.) as long as your code expects them in the inputs dictionary. If you want to exclude certain files or directories from being uploaded, use the --exclude or -e flag.

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Method A: Deploying the model on Inferless Platform

Inferless supports multiple ways of importing your model. For this tutorial, we will use GitHub.

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Step 1: Login to the inferless dashboard can click on Import model button

Navigate to your desired workspace in Inferless and Click on Add a custom model button that you see on the top right. An import wizard will open up.

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Step 2: Follow the UI to complete the model Import

  • Select the GitHub/GitLab Integration option to connect your source code repository with the deployment environment.
  • Navigate to the specific GitHub repository that contains your model’s code. Here, you will need to identify and enter the name of the model you wish to import.
  • Choose the appropriate type of machine that suits your model’s requirements. Additionally, specify the minimum and maximum number of replicas to define the scalability range for deploying your model.
  • Optionally, you have the option to enable automatic build and deployment. This feature triggers a new deployment automatically whenever there is a new code push to your repository.
  • If your model requires additional software packages, configure the Custom Runtime settings by including necessary pip or apt packages. Also, set up environment variables such as Inference Timeout, Container Concurrency, and Scale Down Timeout to tailor the runtime environment according to your needs.
  • Wait for the validation process to complete, ensuring that all settings are correct and functional. Once validation is successful, click on the “Import” button to finalize the import of your model.

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Step 3: Wait for the model build to complete usually takes ~5-10 minutes

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Step 4: Use the APIs to call the model

Once the model is in ‘Active’ status you can click on the ‘API’ page to call the model

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Here is the Demo:

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Method B: Deploying the model on Inferless CLI

Inferless allows you to deploy your model using Inferless-CLI. Follow the steps to deploy using Inferless CLI.

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Clone the repository of the model

Let’s begin by cloning the model repository: 
git clone https://github.com/inferless/nanonets-ocr-s.git

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Deploy the Model

To deploy the model using Inferless CLI, execute the following command: 
inferless deploy --gpu A10 --runtime inferless-runtime-config.yaml
Explanation of the Command:
  • --gpu A10: Specifies the GPU type for deployment. Available options include A10, A100, and T4.
  • --runtime inferless-runtime-config.yaml: Defines the runtime configuration file. If not specified, the default Inferless runtime is used.