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Systems that had to survive the bad day.

Four systems where getting it wrong has a price: what each one does, how it fails safely, and what it changed. Clients stay anonymous unless they agreed otherwise.

Visa applicationsIn production

An agent that completes visa filings

An AI agent fills visa applications from the applicant's documents, and a browser extension carries them into official portals that have no API.

  • Schengen, US, UK, Turkey, UAE and more
  • Visa services platform (NDA)
Read the case studyJava & Spring Boot, AWS Bedrock, RabbitMQ, Stripe
Visa agent: Schengen tourist visa
  • My wife is travelling with me. She has her own passport.
Passport number
···
Travel dates
···
Co-applicant
···
Bank statement
···
EUSchengen visa0 of 4 fields
Browser extension: fills the official visa portalWaiting

Healthcare claimsIn production

Claims intake and EDI reconciliation for US health plans

Every claim file traced from SFTP drop to payer acknowledgement, across several US health plans with their own rules.

  • Multiple US health plans
  • 837 claims reconciled against TA1, 999 and 277
Read the case studyJava & Spring Boot, AWS S3 & SQS, PostgreSQL, X12 EDI
Claims intake: one batch, end to end
  1. Batch received from SFTPMoved to S3 with a manifest; duplicate drops are ignored
  2. Pages prepared and extractedImages cleaned before recognition runs
  3. Plan rules appliedNormalization and validation for this health plan's module
  4. 837 sent, TA1 and 999 acceptedEnvelope and syntax acknowledgements matched
  5. 277 not receivedClaim stays open for follow-up until it arrives
837Batch 2291, claims submitted0 of 5

Banking identityIn production

Customer identity and transaction signing for a retail bank

One customer identity kept consistent across four banking systems, with half-finished changes undone automatically.

  • Retail bank, European banking group
  • Four systems kept consistent per change
Read the case studyJava & Spring Boot, Keycloak, OAuth 2.0 / OIDC, HID authentication
Customer identity: creation that fails halfway
  1. Request validatedRequired fields and uniqueness checked before any system is touched
  2. Authenticator user createdCustomer registered on the device platform
  3. Login account failedIdentity provider rejected the account
  4. Authenticator user removedCompensating step undoes the earlier one
  5. Operation loggedRequest and outcome written to the identity audit log
IDNew customer, rolled back cleanly0 of 5

Geo-verified mediaValidated proof of concept

3DIN: geo-verified photo and video capture

Photos and video that carry where, when and which way the camera pointed, from the phone all the way to the map.

  • Architecture to working product
  • iOS, Android and web
Read the case studySpring Boot, React Native, Next.js, FFmpeg
3DIN: from camera to map
  1. Captured in the fieldGPS position and a continuous compass log recorded with the video
  2. Uploaded in chunksResumable session survives a dropped mobile connection
  3. Checksum verifiedSHA-256 of the assembled file matches the one sent by the phone
  4. Context burned into the frameFFmpeg adds compass overlay, coordinates and timestamp
  5. Published to the event mapVisibility checked against the event's permission model
GPSVideo, 42 s, 1,218 bearings0 of 5

Also built

  • FlexiBookAppointment booking platform: companies, staff, customers, bookings and notifications.Spring Boot, Keycloak, Gradle
  • Druga strana matematikeMath education portal where admins publish blog posts, tests and practice problems.Java, Spring Boot, PostgreSQL, React, Next.js
  • OblikoOnline shop.Java, Spring Boot, PostgreSQL, React, Next.js
  • Miltom DMSDocument management system.Java, Spring Boot, PostgreSQL, React, Next.js

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