Integrations Engineer

Location: London (UK)

Department: Engineering

Location Type: IN_OFFICE

Employment Type: FULL_TIME

About HASH

About the role

Requirements

• Strong production experience with both TypeScript and Python
• Experience personally building and maintaining multiple connectors to third-party APIs, SDKs, databases or services
• A solid understanding of HTTP, REST, GraphQL, webhooks, OAuth 2.0 and common authentication patterns
• A genuine appetite for reverse-engineering poorly documented integration surfaces by reading client code, inspecting network behavior, testing hypotheses and comparing real payloads
• Experience handling the realities of external systems: pagination, rate limits, partial failure, retries, deduplication, idempotency, eventual consistency and breaking API changes
• An obsession with semantic modeling: the ability to identify the real-world concepts behind unfamiliar data and map them into common types without discarding source-specific meaning
• Experience building asynchronous or event-driven services, including queues, workers, scheduling and backfills
• Strong testing instincts, including unit, integration, contract and end-to-end testing where appropriate
• The ability to diagnose failures across several systems using logs, metrics, traces and careful reproduction
• Good security judgment around credentials, secrets, permissions, tenant isolation and sensitive customer data
• High agency and the ability to take an integration from incomplete documentation and a real customer need to a dependable production implementation
• Clear written and spoken communication, including the ability to work directly with customers and external technical teams when necessary

What you'll do

• Build new connectors between HASH and SaaS applications, communications tools, enterprise services and customer APIs
• Maintain existing connectors as upstream APIs, authentication flows, payloads and product behavior change
• Work comfortably from excellent public API documentation when it exists
• Reverse-engineer poorly documented or unofficial integration surfaces where authorized and appropriate, using network inspection, client behavior, SDKs, experiments and careful validation
• Design reliable full and incremental synchronization, including pagination, checkpoints, backfills and recovery after partial failure
• Implement OAuth, API-key and service-account authentication flows and manage credentials securely
• Consume webhooks and event streams, and reconcile them with polling or scheduled sync where necessary
• Build safe two-way synchronization that respects source-system permissions and avoids loops, duplication or unintended writes
• Determine what external fields and objects actually mean, rather than mechanically reproducing their source shape
• Map heterogeneous source schemas into common HASH entity, relationship and property types while preserving source identity, provenance, time and important source-specific distinctions
• Reconcile several services' representations of the same real-world concepts and improve shared semantic schemas as new evidence appears
• Handle schema and API evolution without silently corrupting or dropping customer data
• Create realistic fixtures, mocks and contract tests for third-party systems that are difficult to reproduce locally
• Write clear documentation for users and engineers creating or operating integrations
• Work with AI Success Engineers and customers to understand source systems, data semantics and deployment constraints
• Feed repeated connector requirements back to the engineers who own HASH's surrounding integration infrastructure
• Contribute improvements back to HASH's open-source codebases
• Use AI-assisted development thoughtfully to accelerate connector implementation and schema mapping while retaining responsibility for correctness and maintainability

Why HASH

• Build the integration layer for an open-source platform spanning knowledge graphs, process models, simulations and AI
• Work on synchronization where provenance, history and semantic meaning matter—not merely moving rows from one place to another
• Become expert in a wide variety of public, private, polished and eccentric services
• Combine API reverse-engineering with unusually deep semantic data-modeling work
• Build connectors whose value comes not only from moving data, but from making different systems intelligible together
• Work directly with the engineers building HASH's graph, query, product and deployment infrastructure
• See your work become immediately useful in customer deployments and reusable across the platform
• Join at a moment of rapid growth, with unusual ownership and influence over what HASH becomes
• Be part of a high-agency team that cares about output, ownership and quality

Benefits