ats.text

Design Application Tracking System (ATS) like greenhouse

Requirements:
  1. User should be able to list down openings for a org
  2. User should be able to view an opening
  3. User should be able to fill the application for an opening and submit
  4. User should receive a tracking link upon submission, from where he can track the progress on the application
  5. User should be able to view his submitted applications and retirieve his tracking link

Entity
  1. User
  2. Organisation
  3. Opening
  4. Form
  5. Question
  6. Application Status
  6. Application
  7. Audit
  8. Timeline

Entity Details
  1. User
    id
    name
    email
    phone
    status
    ...

  2. Organisation
    id
    name
    email
    phone
    status
    ...

  3. Opening
    id
    name
    domain
    description
    team name
    min yoe
    max yoe
    expected ctc
    ...

  4. Form
    id
    opening id
    List<Question> questions

  5. Question
    id
    statement
    input field type - text / y/n / number / media upload / mandatory consent / phone number / email

  6. Application Status
    id 
    name
    status

  7. Application transition rule
    id
    source status // either * or some status
    destination status // either * or some status
    allow condition // either allow or deny condition can be defined
    deny condition

  6. Application
    id
    user id
    opening id
    status
    data
    timeline
    ...

  7. Audit
    id
    event name
    data
    timestamp
    ...

  8. Timeline
    List<Event> events


Journey:
  1. Org creates an opening
    HR representative from the org logs into the system
    HR representative creates an opening and its associated form by giving the required fields
    HR when listing down the openings should be able to view them 

  2. Candidate applied
    HR from org has already created the opening and its form
    User logs into the system
    User clicks on the opening
    User is rendered the form
    User enters his details
    User hits submit
    System creates and application for the corresponding opening

  3. Org reviews applications and updates
    User has already applied
    HR Rep logs into the system
    HR Rep clicks and opens the applications view for that opening
    System lists down all the applications so far
    HR filters them by status
    HR reviews application and move them to the next step as defined by the org

  4. Candidate tracks the feedback
    User has already applied
    User logs into the system
    User checks his application history
    User clicks the application he's interested in
    System fetches the application, its status and associated timeline of events

Services
1. User service
  a. Responsible for managing user lifecycle
2. Auth service
  a. Responsible for authentication and authorization
3. Org service
  a. Responsible for org lifecycle ie creating, update, fetch, deactivate
4. Opening service
  a. Responsible for opening lifecycle, create, update, deactivate
5. Form service
  a. Responsible for form lifecycle
6. Application service
  a. Responsible for application lifecycle
  b. Application creation, update, timeline, etc
7. Audit service
  a. Event sink, these events are then used for analytics and auditing
8. Timeline service
  a. Responsible for getting timeline for an application using the audit service as the underlying data source
9. Transition service
  a. This is basically a rules engine, which validates if an application transition from one stage to another is valid or not, these rules have to be defined by the org

we have 1 : 1 mapping with form and opening

Repo layer interface // assuming an db backed impl is to be injected by the framework
  
  user repo
    get by id (user id) : Optional<User>
      // fetch by pk

  org repo
    get by id (org id) : Optional<Organisation> // fetch by pk
    save(organisation) : Organisation // upsert method onto the data store

  opening repo
    get by id (opening id) : Optional<Opening> // fetch by pk
    save(opening) : Opening // upsert method onto the data store
    get all by org id (org id, Pageable, filters) : List<Opening> // get all openings for listing, paginated method

  form repo
    get by id (form id) : Optional<Form> // fetch by pk
    get by opening id(opening id) : Optional<Form> // fetch by index on opening id 
    save(form) : Form // upsert method onto the data store

  application repo
    get by id (application id) : Optional<Application> // fetch by pk
    save(application) : Application // upsert
    get all by user id (user id, pageable, filters) : List<Application> // to power the get application history for a user, pageable and filterable api, indexed on user id
    get all by opening id (opening id, pageable, filters) : List<Application> // to power the get all applications for an opening used by HR, pageable and filterable API, indexed on opening id

  Event repo
    append(event) // inserts a new entry of this event
    list(pageable, filters) // lists all the events by certain filters, pageable API, to power the timeline of application
    get by id (event id) // pk based fetch

  Rules repo
    fetch all () // at bootup load all rules in mem and apply them on every transition
    sync (timestamp) // to power rule sync on certain timeout over a loop, fetch by created after last sync timestamp

Service layer : Psuedo code
  
  user service
    get by id (user id)
      repo.getById(user id)
    ...
  
  org service
    get by id (org id)
      repo.getById(org id)
    ...

  opening service
    upsert (opening) : Opening
      validate
      repo.save(opening)

    get by id (id) : Optional<Opening>
      repo.getById(id)

    get all by org id (org id) : List<Opening>
      repo.getAllByOrgId(org id)

  form service 
    upsert (opening) : Opening
      validate
      repo.save(opening)

    get by id (id) : Optional<Opening>
      repo.getById(id)
    
    get by opening id (opening id) : Optional<Opening>
      repo.getByOpeningId(opening id)
    
  application service
    get by id (application id) : Optional<Application>
      repo.getById(application id)

    get all by user id (user id, pageable, filter): List<Application>
      repo.getAllByUserId(userid, pageable, filter)

    get all by opening id (opening id, pageable, filter) : List<Application>
      repo.getAllByOpeningId(opening id, pageable, filter)

    update (application) : Application
      // fetch existing application
      // check delta
      // validate if transition is applicable if done in update
      repo.save(application)

  rule engine
    boot() // load all the rules in mem at boot time
    sync () // fetches rules created or updated after last sync

    run (transition)
      for rule : rules
        rule.apply(transition)

  timeline service
    get by application id (application id)
      eventService.findAllEventsByApplicationId(application id)

  event service
    find by id (event id) : Optional<Event>
      repo.findById(event id)

    consume(event)
      repo.append(event)