FF07 Software development and engineering medior ITengineeringenterpriseB2B

API Developer

Also known as: Backend API Engineer

Designs and builds APIs through which internal and external systems exchange data, documents interfaces and safeguards version control and security of integrations.

The API developer builds the interfaces on which other teams and sometimes external parties build their own software, demanding stability and backward compatibility. Unlike a fullstack developer, they rarely work on a visible user interface, but do work on a contract others must not break. Selection often focuses on programming language, while carefully versioning an API so existing consumers do not break on a change makes the difference in practice between a stable and a contested interface.

Competencies to measure

These are the behavioural and ability constructs in this profile. Each one shows which hrmforce questionnaire measures it.

Competencies to measure	Target level	hrmforce instrument	Assessment method	Behavioural anchor at target level
Abstract and figural reasoning	N4	Ability Scan	Cognitive ability test	Discovers the underlying rule in unfamiliar material with several changing features and uses it to explain deviations.
Accuracy and attention to detail Competency (50-framework): Accuracy	N4	Big Fifty, 360 Feedback	Personality questionnaire	Builds check moments into the own process, keeps track of errors and prevents repetition by adjusting the method.
Working independently Competency (50-framework): Independence	N3	Big Fifty, 15PF, Competency Check	Personality questionnaire	Determines own approach for a full work package, consults colleagues purposefully when unclear and delivers on time without reminders.

Short profile

The ten heaviest skills in this profile. The full profile with every skill, behavioural anchor and assessment method is in the download.

T	Skill	Target level	Weight	Knockout	Assessment method
V	API integration	N5	5	yes	Work sample test
V	Problem analysis	N4	5	yes	Assessment centre
V	Programming	N4	5	yes	Work sample test
V	Software design and architecture	N4	5	yes	Work sample test
A	Abstract and figural reasoning	N4	4	no	Cognitive ability test
V	Modelling and abstraction	N4	4	no	Work sample test
G	Accuracy and attention to detail	N4	4	no	Personality questionnaire
T	Version control and collaboration workflow	N4	4	yes	Work sample test
V	Software testing and quality assurance	N4	4	no	Work sample test
V	Writing technical documentation	N4	4	yes	Work sample test

See all 24 skills in the full profile

Assessment instruments for this job

15 measurable constructs

Work sample test

Representative work sample under standardized conditions

10 measurable constructs

Knowledge test (client-specific)

Professional knowledge test, customized for each client

5 measurable constructs

Competency Check

Behavioral-Level Competency Assessment

5 measurable constructs

Portfolio

Evaluation of prior work against fixed criteria

3 measurable constructs

360 Feedback

Multiple assessments based on behavioral anchors

2 measurable constructs

Ability Scan

Aptitude Test: Verbal, Numerical, and Abstract Reasoning Skills

2 measurable constructs

Big Fifty

Personality questionnaire, 150 items, 25 factors

1 measurable constructs

Structured interview

Behavioral interview with a fixed structure

1 measurable constructs

15PF

Personality Profile, a shorter alternative to the Big Fifty

1 measurable constructs