INTERFACE by apidays 2023 APIs for a “Smart” economy. Embedding AI to deliver Smart APIs and turn into an exponential organization June 28 & 29, 2023 API Green Score : How to reduce the environmental impact of your APIs? Yannick Tremblais, IT Innovation Manager, Groupe Rocher ------ Check out our conferences at https://www.apidays.global/ Do you want to sponsor or talk at one of our conferences? https://apidays.typeform.com/to/ILJeAaV8 Learn more on APIscene, the global media made by the community for the community: https://www.apiscene.io Explore the API ecosystem with the API Landscape: https://apilandscape.apiscene.io/

1. Sustainable API
‘API Numériquement Responsable’
‘Digital API Responsability’

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2
Present in nearly
120 countries
4 BUSINESS SECTORS
COSMETICS
CLOTHING
HOME CARE
WELL-BEING
Yannick Tremblais
IT Innovation Manager
Groupe Rocher

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In 2019 Groupe Rocher adopt the status of “mission-driven company” .
Our mission:
RECONNECT PEOPLE
TO NATURE
Green IT Eco-design
of IS
Responsible
IT usages
IT for Green
2030 GRTS IT RESPONSIBILITY AMBITIONS

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We are sharing our studies to external communities
As we are pioneers on API Ecodesign
As environmental impact is a shared concern
As guideline and calculation rule must be
shared and validated by many to be
recognized
External Communities
Active Member of the API Thinking Community
head of workgroup “Sustainable digital API”
A collective that draws its strength from its members
Since 2020, the 1st French collective dedicated to APIS
Free Network Diversity

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Digital Sustainability
https://en.arcep.fr/uploads/tx_gspublication/press-kit-study-Ademe-Arcep-lot3_march2023.pdf

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Without action to limit the growth of the environmental impact
of digital technology, its carbon footprint could triple between
2020 and 2050 ADEME-Arcep working group document listing potential game-changers in the digital sector

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The API Green Score is a toolkit to help API users, designers and owners to ask themselves
questions about the digital impact of their API
This tool is based on 7 different domains in order to create relevant and realistic metrics that
stakeholders can use.
The evaluation method is shared with all API Persona
(API owners, API consumers, API developers)
Excellent Acceptable Average Poor Very Poor
A B C D E
API Green Score

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• Decommission an unused API
• Deploy API near consumer
• Reduce number of API versions
• Unify API catalog
• Create consumer referential
• Identify API for single usage
• Urbanization with Data Governance
• Exchange with Smallest Size
• Following API payload size
• Prefer Opaque Token to JWT
• API Customer Centricity principles
• API Data / Granularity
• Leverage Odata or GraphQL for DB
APIs
• Data Management
• Dynamic Content
• Optimize queries to limit returned
information
• Collect only required data
• Provide only changed data
• Use cache
• Communicate on Payload size
• API used geolocally close to their
consumers
• Promote event architecture
• Filter data in payload
• Pagination
• Webhook or Business Notification
• AsyncAPI
• Define a basis of criteria for rating
• Provide KPIs (Nb of call, payload
size, nb of equipments used, …)
• Evaluate energy consumption for
one API
• Know language impact for energy
consumption
• Use adaptive infrastructure
• Use as few cloud suppliers as
possible between consumer and
backend
• Be near Data Center
• Define which actions are more
relevant to do to reduce the impact
of API ?
• Name of API Ecoscore
• Guideline resources
• Sharing criteria of evaluation and
methods
• Adapt the communication of each
personas
API Lifecycle Data Exchange Data Architecture
Tools Infrastructure Communication
7 Domains

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API Lifecyle Domain
Impact EcoScore
API Lifecycle
API uses: (who, when, what)
Description Governance
Tools to measure
KPI per API
Example
Have a consumer referential
What is the impact of this referential
on the API Green Score?
Who consumes my API?
What: Which version of API?
When: Which number of asked calls
vs number of calls ? Date of last call?
What is the calls volume ?
API Product Owner
Center of Expertise API
Logs API / Operational Reporting
Analytics API Gateway
To influence the Metrics
API Gateway/API Portal
Nb of call per consumer
Nb of consumers per API
Nb of versions per API (US03)
Location of consumers
Documentation quality (US06)
What is the API Footprint?
API Order 10000/ call / month
API last Call
Nb of Consumers who used this API
20%

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Data Exchange Domain
Data Exchange
API uses: How to exchange information between information systems
Description Governance
Tools to measure
KPI per API
Examples
Impact EcoScore
Make sure APIs are eco
designed
How we exchange data,
Payload size
Message type / integration
pattern type
Call frequency / cache
API Product Owner
API developer
Application Owner
Api gateway / API portal
E2E observability
Nb of calls per consumer
Calls volume
API Payload average size (DE11)
Integration Layer Payload
Integration pattern
Cache performance (DE01, DE02, DE03)
Filtering data for calling backend
Orchestration
Consume only relevant data
20%

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Data Domain
Description
Impact EcoScore
Data
API uses: Govern Business Object (naming convention, modelization, pivot format)
Governance
Tools to measure
KPI per API
Example
Understand the use case and
type of data implicated
Business object
Expose only needed data
Data should only be stored in a
single point of truth
Data should be stored in an
unique and secured point
Data Product Owner
Application Owner
Data Catalog
DataPedia, DataService
Cache management (DE03)
Payload average size
Data format (JSon/XML) (DE01)
Compressed Payload usage
Shared business objects depending on
usage
Avoid duplicated data
20%

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To simplify your task and assist you in directing your efforts effectively, we have
established categories:
Categories are used to adjust the weighting of rules.
Depending on your organization, you can have a better impact on some categories.
Archi Design Usage Logs
4 categories

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Archi Design Usage Logs
API Lifecycle Data Exchange Data Architecture
Tools Infrastructure Communication
4 Categories
7 Domains
Domains vs Categories

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We have 2 ways to evaluate:
• Boolean: true/false
• Rate: calculation should be shared with persona, to avoid any misunderstanding
If some rules are not relevant - ex GraphQL (DE09), you can remove them from your
referential and adapt with your own weighting
If some rules are not explicit enough, it is important to share them with all personas
Evaluation Grid: Some precisions before starting
Archi Design Usage Logs
Rule
AR01
…
Rule
ARxx
Rule
DE01
… Rule DExx Rule
US01
…
Rule
USxx
Rule
LO01
…
Rule
LOxx
4 Categories
Usage (US): 25 %
Each category are rules based on 7 domains
(Architecture, Data, API Lifecycle, Data Exchange, Tools,
Infrastructure, Communication)
Logs (LO): 10%
Design (DE): 40%
Architecture (AR): 25%
Each rule (US01, LO01, LO02…) has a score and
its category has a weighting

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Evaluation Grid: Results
Excellent Acceptable Average Poor Very Poor Not evaluted
A B C D E N.C
>=6000 6000<>=3000 3000<>=2000 2000<>=1000 <1000

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AR05: Carbon Footprint Dashboard
Some cloud providers produce carbon footprint dashboard.
You can implement your own or adapt it based on your infrastructure and be close to your usage.
Ex: evaluation the impact of compute, network, disk and divided by the number of calls of the evaluate
API.
Expected gain: Network, compute
network compute Storage
Architecture

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DE01: Prefer an exchange format with the smallest size (JSON is smaller than XML).
One of the structuring questions when designing an API is the selection of the exchange format to use. If the choice is often made
by technical constraints or personal affinities, the durability aspect is also to be taken into account.
Indeed, there are exchange formats that are heavier than others. For example, JSON is smaller than XML. The second format will
therefore have a stronger impact on the network, the computing and the storage.
In the interest of sustainability, we recommend to use a lighter exchange format to reduce the bandwidth consumed for the
requests, the compute and storage resources consumption used to process and store the payloads.
Expected gain: Network, compute and storage impact reduced
network compute storage
Data Exchange

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xml json Gain
717 B 623 B 94 B (-13%)
nb call /day 2 000 000 1,33 GB 1,16 GB 0,17 GB
nb call/month
(30)
60 000 000 40,06 GB 34.81 GB 5,25 GB
<?xml version="1.0" encoding="UTF-8"?>
<Catalog>
<Book id="bk101">
<Author>Garghentini, Davide</Author>
<Title>XML Developer's Guide</Title>
<Genre>Computer</Genre>
<Price>44.95</Price>
<PublishDate>2000-10-01</PublishDate>
<Description>An in-depth look at creating applications
with XML.</Description>
</Book>
<Book id="bk102">
<Author>Garcia, Debra</Author>
<Title>Midnight Rain</Title>
<Genre>Fantasy</Genre>
<Price>5.95</Price>
<PublishDate>2000-12-16</PublishDate>
<Description>A former architect battles corporate zombies,
an evil sorceress, and her own childhood to become queen
of the world.</Description>
</Book>
</Catalog>
{
"Catalog": {
"Book": [
{
"Author": "Garghentini, Davide",
"Title": "XML Developer's Guide",
"Genre": "Computer",
"Price": "44.95",
"PublishDate": "2000-10-01",
"Description": "An in-depth look at creating applicationsn
with XML.",
"_id": "bk101"
},
{
"Author": "Garcia, Debra",
"Title": "Midnight Rain",
"Genre": "Fantasy",
"Price": "5.95",
"PublishDate": "2000-12-16",
"Description": "A former architect battles corporate zombies,n
an evil sorceress, and her own childhood to become queenn of the world.",
"_id": "bk102"
}
]
}
}
717 bytes bookstore.xml 623 bytes bookstore.json

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DE02/DE03/DE05: Use cache to avoid useless requests and preserve compute resources.
The use of a cache has become common in computer architectures to store frequently used information on a fast
storage.
In addition to improving the response time of APIs, and therefore the consumer's experience of the service, it also
saves computational resources by avoiding executing the same query on the same data multiple times.
It is recommended to place a cache in front of each brick of an architecture returning data (API, database, frontend
application, ...) and close to the users to preserve compute resources and improve performances of the API.
Expected gain: Compute resources saved & Network impact reduced
network compute storage
Data Data Exchange

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US01 : Use query parameters for GET Methods
Optimize queries to limit the information returned to what is strictly necessary.
It is often observed that requests made on APIs are not precise enough, which returns a volume of information greater than necessary.
This results in increased bandwidth consumption during exchanges.
The best practice is to create precise requests that return, as much as possible, the strictly necessary information, thus avoiding the
transfer of useless information.
This rule is linked to DE08 : “Implement filters to limit which fields are returned by the API ”
Expected gain: Network, compute
network compute storage
Data Exchange

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https://api-adresse.data.gouv.fr/search
curl "https://api-adresse.data.gouv.fr/search/?q=10+av"
https://api-adresse.data.gouv.fr/search/?q=10+av&limit=100
https://api-adresse.data.gouv.fr/search/?q=10+av
5 results
Payload : 2,57 KB
100 results
Payload 42,9 KB
https://api-adresse.data.gouv.fr/search/?q=10+av&limit=1000

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curl l"https://api.spotify.com/v1/browse/categories"
https://api.spotify.com/v1/browse/categories?offset=30
&limit=50
https://api.spotify.com/v1/browse/categories?offset=0
&limit=50
48 results
Payload : 16,37 KB
18 results
Payload 6,81 KB

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LO01: Collect only required data and use the right retention time according to the business requirements.
It is quite common for applications to store a large amount of useless information without time limit.
This results in an excessive consumption of storage services for data that will not be used or no longer used.
It is necessary to clean up the data in order to keep only the data that is useful and to define a coherent retention
policy in order to delete them once their validity or exploitation period has passed.
Expected gain: Volume of data stored reduced & Network impact reduced
network compute storage
Tools

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https://www.elastic.co/guide/en/elasticsearch/reference/current/rollup-overview.html
detail by each API call
detail by each hour call
keep details by brand/country/method
aggregate : Average(Response Time), sum (nb of
call) by hour
automatic rollup process
to reduce granularity
Major Impact: save disk space

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• Define log retention per services/domain
• Define log rotation (rollup)
• Keep unit date for 45 days, and aggregate them(mn/hour)
➔ Reduce size of Elastic indices to 4Go /month

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https://institutnr.org/guide-de-reference-de-conception-responsable
Institut du Numérique Responsable
Institute of Digital Responsability
https://gr491.isit-europe.org/en

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https://greensoftware.foundation
https://patterns.greensoftware.foundation
Green Software Foundation

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https://collectif.greenit.fr/
Collectif Numérique Responsable (CNUMR)
https://github.com/cnumr

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https://www.ecocode.io/
EcoCode
https://github.com/green-code-initiative

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https://www.collectif-api-thinking.com
This is the beginning of our journey; we need you to contribute!
"Transform your API strategy with the industry's leading
practices for environmental sustainability.”