Instant search and offline access to any API documentation you may need. Dash is an API Documentation Browser that gives your iPad and iPhone instant offline access to 150+ API documentation sets (for a full list, see below). Offline Documentation: iOS, macOS, watchOS, tvOS, Swift,.NET Framewor. Technical documentation for developing for Amazon Alexa, Amazon Appstore, and Fire devices. End users typically would not expect 1.1 + 2.2 to display as 3.000003 as it does with binary floating point. The exactness carries over into arithmetic. In decimal floating point, 0.1 + 0.1 + 0.1-0.3 is exactly equal to zero. In binary floating point, the result is 5.257827e-017. While near to zero, the differences prevent. Pip install dash1.16.3 Note: starting with dash 0.37.0, dash automatically installs dash-renderer, dash-core-components, dash-html-components, and dash-table, using known-compatible versions of each.
FastAPI framework, high performance, easy to learn, fast to code, ready for production
Documentation: https://fastapi.tiangolo.com
Blocs 3 3 0 cr2. Source Code: https://github.com/tiangolo/fastapi
FastAPI is a modern, fast (high-performance), web framework for building APIs with Python 3.6+ based on standard Python type hints.
The key features are:
Fast: Very high performance, on par with NodeJS and Go (thanks to Starlette and Pydantic). One of the fastest Python frameworks available.
Fast to code: Increase the speed to develop features by about 200% to 300%. *
- Fewer bugs: Reduce about 40% of human (developer) induced errors. *
- Intuitive: Great editor support. Completion everywhere. Less time debugging.
- Easy: Designed to be easy to use and learn. Less time reading docs.
- Short: Minimize code duplication. Multiple features from each parameter declaration. Fewer bugs.
- Robust: Get production-ready code. With automatic interactive documentation.
- Standards-based: Based on (and fully compatible with) the open standards for APIs: OpenAPI (previously known as Swagger) and JSON Schema.
* estimation based on tests on an internal development team, building production applications.
Opinions¶
'[..] I'm using FastAPI a ton these days. [..] I'm actually planning to use it for all of my team's ML services at Microsoft. Some of them are getting integrated into the core Windows product and some Office products.'
'We adopted the FastAPI library to spawn a REST server that can be queried to obtain predictions. [for Ludwig]'
'Netflix is pleased to announce the open-source release of our crisis management orchestration framework: Dispatch! [built with FastAPI]'
'I'm over the moon excited about FastAPI. It's so fun!'
'Honestly, what you've built looks super solid and polished. In many ways, it's what I wanted Hug to be - it's really inspiring to see someone build that.'
'If you're looking to learn one modern framework for building REST APIs, check out FastAPI [..] It's fast, easy to use and easy to learn [..]'
'We've switched over to FastAPI for our APIs [..] I think you'll like it [..]'
Typer, the FastAPI of CLIs¶
If you are building a CLI app to be used in the terminal instead of a web API, check out Typer.
Typer is FastAPI's little sibling. And it's intended to be the FastAPI of CLIs. ⌨️ 🚀
Requirements¶
Python 3.6+
FastAPI stands on the shoulders of giants:
- Starlette for the web parts.
- Pydantic for the data parts.
Installation¶
You will also need an ASGI server, for production such as Uvicorn or Hypercorn.
Example¶
Create it¶
- Create a file
main.py
with:
async def
..If your code uses async
/ await
, use async def
:
Note:
If you don't know, check the 'In a hurry?' section about async
and await
in the docs.
Run it¶
Run the server with:
uvicorn main:app --reload
..The command uvicorn main:app
refers to:
main
: the filemain.py
(the Python 'module').app
: the object created inside ofmain.py
with the lineapp = FastAPI()
.--reload
: make the server restart after code changes. Only do this for development.
Check it¶
Open your browser at http://127.0.0.1:8000/items/5?q=somequery.
You will see the JSON response as:
You already created an API that:
- Receives HTTP requests in the paths
/
and/items/{item_id}
. - Both paths take
GET
operations (also known as HTTP methods). - The path
/items/{item_id}
has a path parameteritem_id
that should be anint
. - The path
/items/{item_id}
has an optionalstr
query parameterq
.
Interactive API docs¶
Now go to http://127.0.0.1:8000/docs.
You will see the automatic interactive API documentation (provided by Swagger UI):
Alternative API docs¶
And now, go to http://127.0.0.1:8000/redoc.
You will see the alternative automatic documentation (provided by ReDoc):
Example upgrade¶
Now modify the file main.py
to receive a body from a PUT
request.
Declare the body using standard Python types, thanks to Pydantic.
The server should reload automatically (because you added --reload
to the uvicorn
command above).
Interactive API docs upgrade¶
Now go to http://127.0.0.1:8000/docs.
- The interactive API documentation will be automatically updated, including the new body:
- Click on the button 'Try it out', it allows you to fill the parameters and directly interact with the API:
- Then click on the 'Execute' button, the user interface will communicate with your API, send the parameters, get the results and show them on the screen:
Alternative API docs upgrade¶
uvicorn main:app --reload
..The command uvicorn main:app
refers to:
main
: the filemain.py
(the Python 'module').app
: the object created inside ofmain.py
with the lineapp = FastAPI()
.--reload
: make the server restart after code changes. Only do this for development.
Check it¶
Open your browser at http://127.0.0.1:8000/items/5?q=somequery.
You will see the JSON response as:
You already created an API that:
- Receives HTTP requests in the paths
/
and/items/{item_id}
. - Both paths take
GET
operations (also known as HTTP methods). - The path
/items/{item_id}
has a path parameteritem_id
that should be anint
. - The path
/items/{item_id}
has an optionalstr
query parameterq
.
Interactive API docs¶
Now go to http://127.0.0.1:8000/docs.
You will see the automatic interactive API documentation (provided by Swagger UI):
Alternative API docs¶
And now, go to http://127.0.0.1:8000/redoc.
You will see the alternative automatic documentation (provided by ReDoc):
Example upgrade¶
Now modify the file main.py
to receive a body from a PUT
request.
Declare the body using standard Python types, thanks to Pydantic.
The server should reload automatically (because you added --reload
to the uvicorn
command above).
Interactive API docs upgrade¶
Now go to http://127.0.0.1:8000/docs.
- The interactive API documentation will be automatically updated, including the new body:
- Click on the button 'Try it out', it allows you to fill the parameters and directly interact with the API:
- Then click on the 'Execute' button, the user interface will communicate with your API, send the parameters, get the results and show them on the screen:
Alternative API docs upgrade¶
And now, go to http://127.0.0.1:8000/redoc.
- The alternative documentation will also reflect the new query parameter and body:
Recap¶
In summary, you declare once the types of parameters, body, etc. as function parameters.
1password 7 4 2016. You do that with standard modern Python types.
You don't have to learn a new syntax, the methods or classes of a specific library, etc.
Just standard Python 3.6+.
For example, for an int
:
or for a more complex Item
model:
..and with that single declaration you get:
- Editor support, including:
- Completion.
- Type checks.
- Validation of data:
- Automatic and clear errors when the data is invalid.
- Validation even for deeply nested JSON objects.
- Conversion of input data: coming from the network to Python data and types. Reading from:
- JSON.
- Path parameters.
- Query parameters.
- Cookies.
- Headers.
- Forms.
- Files.
- Conversion of output data: converting from Python data and types to network data (as JSON):
- Convert Python types (
str
,int
,float
,bool
,list
, etc). datetime
objects.UUID
objects.- Database models.
- ..and many more.
- Convert Python types (
- Automatic interactive API documentation, including 2 alternative user interfaces:
- Swagger UI.
- ReDoc.
Coming back to the previous code example, FastAPI will:
- Validate that there is an
item_id
in the path forGET
andPUT
requests. - Validate that the
item_id
is of typeint
forGET
andPUT
requests.- If it is not, the client will see a useful, clear error.
- Check if there is an optional query parameter named
q
(as inhttp://127.0.0.1:8000/items/foo?q=somequery
) forGET
requests.- As the
q
parameter is declared with= None
, it is optional. - Without the
None
it would be required (as is the body in the case withPUT
).
- As the
- For
PUT
requests to/items/{item_id}
, Read the body as JSON:- Check that it has a required attribute
name
that should be astr
. - Check that it has a required attribute
price
that has to be afloat
. - Check that it has an optional attribute
is_offer
, that should be abool
, if present. - All this would also work for deeply nested JSON objects.
- Check that it has a required attribute
- Convert from and to JSON automatically.
- Document everything with OpenAPI, that can be used by:
- Interactive documentation systems.
- Automatic client code generation systems, for many languages.
- Provide 2 interactive documentation web interfaces directly.
We just scratched the surface, but you already get the idea of how it all works.
Dash Api Documentation Browser 5 1 3g
Try changing the line with:
..from:
..to:
..and see how your editor will auto-complete the attributes and know their types:
For a more complete example including more features, see the Tutorial - User Guide.
Spoiler alert: the tutorial - user guide includes:
- Declaration of parameters from other different places as: headers, cookies, form fields and files.
- How to set validation constraints as
maximum_length
orregex
. - A very powerful and easy to use Dependency Injection system.
- Security and authentication, including support for OAuth2 with JWT tokens and HTTP Basic auth.
- More advanced (but equally easy) techniques for declaring deeply nested JSON models (thanks to Pydantic).
- Many extra features (thanks to Starlette) as:
- WebSockets
- GraphQL
- extremely easy tests based on
requests
andpytest
- CORS
- Cookie Sessions
- ..and more.
Performance¶
Independent TechEmpower benchmarks show FastAPI applications running under Uvicorn as one of the fastest Python frameworks available, only below Starlette and Uvicorn themselves (used internally by FastAPI). (*)
To understand more about it, see the section Benchmarks.
Api Documentation Tool
Optional Dependencies¶
Used by Pydantic:
ujson
- for faster JSON 'parsing'.email_validator
- for email validation.
Dash Api Documentation Browser 5 1 32
Used by Starlette:
requests
- Required if you want to use theTestClient
.aiofiles
- Required if you want to useFileResponse
orStaticFiles
.jinja2
- Required if you want to use the default template configuration.python-multipart
- Required if you want to support form 'parsing', withrequest.form()
.itsdangerous
- Required forSessionMiddleware
support.pyyaml
- Required for Starlette'sSchemaGenerator
support (you probably don't need it with FastAPI).graphene
- Required forGraphQLApp
support.ujson
- Required if you want to useUJSONResponse
.
Used by FastAPI / Starlette:
uvicorn
- for the server that loads and serves your application.orjson
- Required if you want to useORJSONResponse
.
You can install all of these with pip install fastapi[all]
.
License¶
This project is licensed under the terms of the MIT license.