# Duolingo - **Answer**: Duolingo builds mostly with Python, Kotlin, SQL, Java. Its stack also includes AWS, Datadog, OpenTelemetry, Google BigQuery. Python is named in 19 of the 61 job postings Duolingo published in the last 12 months (31%). Counted by Alion from the job postings of Duolingo, updated Nov 13, 2026. - **Window days**: 365 - **Postings analysed**: 61 - **Open postings**: 25 - **Technologies in use**: 65 - **Modernity score**: 88 - **Ai adoption**: yes - **License**: CC BY-SA 4.0 ## Company - **Id**: 19161 - **Name**: Duolingo - **Domain**: duolingo.com - **Url**: ## Technologies - **Machine Learning** — Layer: practices; Postings: 21; Share: 0.3443; Required: 21; Open postings: 10; First seen: 2025-12-02 - **Python** — Layer: languages; Postings: 19; Share: 0.3115; Required: 19; Open postings: 8; First seen: 2026-06-09 - **Kotlin** — Layer: languages; Postings: 12; Share: 0.1967; Required: 12; Open postings: 5; First seen: 2026-06-09 - **SQL** — Layer: languages; Postings: 10; Share: 0.1639; Required: 10; Open postings: 3; First seen: 2026-07-28 - **A/B Testing** — Layer: practices; Postings: 10; Share: 0.1639; Required: 8; Open postings: 3; First seen: 2026-07-10 - **Java** — Layer: languages; Postings: 9; Share: 0.1475; Required: 9; Open postings: 4; First seen: 2026-06-09 - **Swift** — Layer: languages; Postings: 7; Share: 0.1148; Required: 7; Open postings: 4; First seen: 2025-12-02 - **LLM** — Layer: ai; Postings: 6; Share: 0.0984; Required: 6; Open postings: 3; First seen: 2026-06-09 - **AWS** — Layer: cloud; Postings: 5; Share: 0.082; Required: 5; Open postings: 3; First seen: 2026-07-17 - **Fine-tuning** — Layer: practices; Postings: 5; Share: 0.082; Required: 5; Open postings: 2; First seen: 2026-06-26 - **Reinforcement Learning** — Layer: practices; Postings: 5; Share: 0.082; Required: 5; Open postings: 2; First seen: 2026-06-26 - **CI/CD** — Layer: practices; Postings: 4; Share: 0.0656; Required: 4; Open postings: 2; First seen: 2026-08-28 - **AI Agents** — Layer: practices; Postings: 3; Share: 0.0492; Required: 3; Open postings: 0; First seen: 2026-06-12 - **Datadog** — Layer: cloud; Postings: 3; Share: 0.0492; Required: 3; Open postings: 2; First seen: 2026-06-09 - **Figma** — Layer: cloud; Postings: 3; Share: 0.0492; Required: 3; Open postings: 1; First seen: 2026-10-05 - **Grafana** — Layer: cloud; Postings: 3; Share: 0.0492; Required: 3; Open postings: 2; First seen: 2026-06-09 - **Human-in-the-Loop** — Layer: practices; Postings: 3; Share: 0.0492; Required: 3; Open postings: 1; First seen: 2026-08-17 - **Kubernetes** — Layer: cloud; Postings: 3; Share: 0.0492; Required: 3; Open postings: 1; First seen: 2026-09-02 - **OpenTelemetry** — Layer: frameworks; Postings: 3; Share: 0.0492; Required: 3; Open postings: 2; First seen: 2026-06-09 - **Prometheus** — Layer: tools; Postings: 3; Share: 0.0492; Required: 3; Open postings: 2; First seen: 2026-06-09 - **Prompt Engineering** — Layer: practices; Postings: 3; Share: 0.0492; Required: 3; Open postings: 2; First seen: 2026-08-17 - **Terraform** — Layer: tools; Postings: 3; Share: 0.0492; Required: 3; Open postings: 1; First seen: 2026-08-28 - **iOS SDK** — Layer: cloud; Postings: 3; Share: 0.0492; Required: 3; Open postings: 2; First seen: 2025-12-02 - **Speech Recognition** — Layer: practices; Postings: 3; Share: 0.0492; Required: 1; Open postings: 1; First seen: 2026-07-29 - **Text-to-Speech** — Layer: practices; Postings: 3; Share: 0.0492; Required: 1; Open postings: 1; First seen: 2026-07-29 - **Cursor** — Layer: tools; Postings: 2; Share: 0.0328; Required: 2; Open postings: 1; First seen: 2025-10-07 - **Docker** — Layer: tools; Postings: 2; Share: 0.0328; Required: 2; Open postings: 1; First seen: 2026-09-04 - **GCP** — Layer: cloud; Postings: 2; Share: 0.0328; Required: 2; Open postings: 1; First seen: 2026-09-02 - **Google BigQuery** — Layer: data; Postings: 2; Share: 0.0328; Required: 2; Open postings: 1; First seen: 2026-10-15 - **Jetpack Compose** — Layer: frameworks; Postings: 2; Share: 0.0328; Required: 2; Open postings: 0; First seen: 2026-08-25 - **Kotlin Coroutines** — Layer: other; Postings: 2; Share: 0.0328; Required: 2; Open postings: 0; First seen: 2026-08-25 - **MySQL** — Layer: data; Postings: 2; Share: 0.0328; Required: 2; Open postings: 1; First seen: 2026-09-04 - **Okta** — Layer: cloud; Postings: 2; Share: 0.0328; Required: 2; Open postings: 1; First seen: 2026-08-28 - **Platform Engineering** — Layer: practices; Postings: 2; Share: 0.0328; Required: 2; Open postings: 1; First seen: 2026-06-09 - **PostgreSQL** — Layer: data; Postings: 2; Share: 0.0328; Required: 2; Open postings: 1; First seen: 2026-09-04 - **SLI/SLO/SLA** — Layer: practices; Postings: 2; Share: 0.0328; Required: 2; Open postings: 1; First seen: 2026-08-28 - **Sentry** — Layer: cloud; Postings: 2; Share: 0.0328; Required: 2; Open postings: 0; First seen: 2026-08-25 - **Snowflake** — Layer: data; Postings: 2; Share: 0.0328; Required: 2; Open postings: 1; First seen: 2026-10-15 - **dbt** — Layer: tools; Postings: 2; Share: 0.0328; Required: 2; Open postings: 1; First seen: 2026-10-15 - **Computer Vision** — Layer: practices; Postings: 2; Share: 0.0328; Required: 0; Open postings: 1; First seen: 2026-06-26 - **Multimodal AI** — Layer: practices; Postings: 2; Share: 0.0328; Required: 0; Open postings: 0; First seen: 2026-07-29 - **Adobe Photoshop** — Layer: tools; Postings: 1; Share: 0.0164; Required: 1; Open postings: 0; First seen: 2026-10-05 - **Adobe Premiere Pro** — Layer: tools; Postings: 1; Share: 0.0164; Required: 1; Open postings: 0; First seen: 2026-10-21 - **Adobe XD** — Layer: tools; Postings: 1; Share: 0.0164; Required: 1; Open postings: 1; First seen: 2026-11-09 - **Apex** — Layer: languages; Postings: 1; Share: 0.0164; Required: 1; Open postings: 0; First seen: 2026-06-12 - **ArgoCD** — Layer: tools; Postings: 1; Share: 0.0164; Required: 1; Open postings: 0; First seen: 2026-09-02 - **Azure** — Layer: cloud; Postings: 1; Share: 0.0164; Required: 1; Open postings: 0; First seen: 2026-09-02 - **C++** — Layer: languages; Postings: 1; Share: 0.0164; Required: 1; Open postings: 1; First seen: 2026-11-06 - **ChatGPT** — Layer: ai; Postings: 1; Share: 0.0164; Required: 1; Open postings: 0; First seen: 2025-10-07 - **CloudFormation** — Layer: tools; Postings: 1; Share: 0.0164; Required: 1; Open postings: 0; First seen: 2026-09-02 - … 15 more in the JSON form ## Changes ### First appeared - **Google BigQuery** — First seen: 2026-10-15 - **Snowflake** — First seen: 2026-10-15 - **dbt** — First seen: 2026-10-15 - **Figma** — First seen: 2026-10-05 - **Docker** — First seen: 2026-09-04 - **MySQL** — First seen: 2026-09-04 - **PostgreSQL** — First seen: 2026-09-04 - **Kubernetes** — First seen: 2026-09-02 ### Rising - **SQL** — Share from: 8; Share to: 23 - **CI/CD** — Share from: 0; Share to: 11 - **Figma** — Share from: 0; Share to: 9 - **Human-in-the-Loop** — Share from: 0; Share to: 9 - **Kubernetes** — Share from: 0; Share to: 9 - **Prompt Engineering** — Share from: 0; Share to: 9 - **Terraform** — Share from: 0; Share to: 9 - **AWS** — Share from: 4; Share to: 11 ### Falling - **Machine Learning** — Share from: 50; Share to: 20 - **Swift** — Share from: 17; Share to: 3 - **Fine-tuning** — Share from: 17; Share to: 3 - **Reinforcement Learning** — Share from: 17; Share to: 3 - **Datadog** — Share from: 13; Share to: 0 - **Grafana** — Share from: 13; Share to: 0 - **OpenTelemetry** — Share from: 13; Share to: 0 - **Prometheus** — Share from: 13; Share to: 0 ## Similar stacks - [Verkada](https://alion.io/company/verkada/technologies) — Shared technologies: 54 - [Robinhood](https://alion.io/company/robinhood/technologies) — Shared technologies: 54 - [Zillow](https://alion.io/company/zillow/technologies) — Shared technologies: 54 - [Canva](https://alion.io/company/canva/technologies) — Shared technologies: 53 - [Match Group](https://alion.io/company/match-group/technologies) — Shared technologies: 52 - [Mercari](https://alion.io/company/mercari/technologies) — Shared technologies: 52 - [eBay](https://alion.io/company/ebay/technologies) — Shared technologies: 57 - [InMobi](https://alion.io/company/inmobi/technologies) — Shared technologies: 55 --- [Page](https://alion.io/company/duolingo-blog/technologies) · [JSON](https://alion.io/company/duolingo-blog/technologies.json) Source: Alion (alion.io), 2026-11-13. 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