Deliveru builds serverless AI-powered recruiting platform on Restate

Deliveru is an AI-powered recruiting platform that automates the manual, time-consuming and non-value-added tasks within the recruiting process.

Restate powers Deliveru's entire recruiting platform, including an autonomous AI recruiting agent that analyzes candidate CVs, diplomas, and certificates for labeling, tagging, and data extraction (skills, education, etc.), as well as workflows that process complex documents and PDFs of more than 100 pages.

Restate basically powers our whole platform from candidate intake to transcription to the orchestration of every workflow that we have.

-- Stephan Gilli, Co-founder at Deliveru

The Challenge

Deliveru's recruiting platform consists of many workflows to handle all aspects of screening candidates and processing documents:

• Processing CVs from multiple sources (LinkedIn, Indeed, job portals)
• Automated skill extraction, normalization, and enhancement
• Document analysis including compliance checks and certificate validation
• Processing interview transcripts

Deliveru needed to implement these workflows in a resilient way with minimal infrastructure management because they were a small team. They didn’t want to deploy all the infrastructure required to implement resilient asynchronous work like queues. So they started looking out for a Durable Execution platform to serve as the basis for the platform.

Why Restate?

When the team started implementing their use case, Restate Cloud was not yet available. Having a cloud offering was a critical factor for them, so they went with another Durable Execution system. While being happy about the durability guarantees, they experienced friction when it came to serverless support, versioning, and the programming model.

Once Restate Cloud became generally available, they immediately migrated and became one of the first Restate Cloud users.

They chose Restate as the basis of their platform, because of the following aspects:

• Reliable execution of async work: Restate runs workflows asynchronously and guarantees completion. For example, when a CV gets uploaded, you can't afford to lose the candidate.

• Strong AWS Lambda support: Deliveru wanted to run their entire application on AWS Lambda. Restate has strong support for AWS Lambda, enabling efficient implementation of long-running workflows with its suspend-on-wait mechanism.

• Zero infrastructure management: With Restate Cloud and AWS Lambda, the small team could focus on building features instead of managing queues and other infrastructure.

• Flexible, well-fitting programming model: Restate’s Virtual Objects were a great fit for modeling candidates and accounts. They are long-lived, retain state, offer concurrency guarantees, and allow to inspect and query their state in the Restate UI.

  We keep every candidate as a virtual object, which allows us to use exclusive function calling. This ensures that only one message is sent at a time, preventing parallel message sending. It gives us the durability we need when orchestrating all these calls, and the dashboard insights are really amazing.

  -- Stephan Gilli, Co-founder at Deliveru

• Safe code evolution: Durable Execution typically requires code to remain unchanged to ensure replay works on recovery. This makes upgrades challenging, often requiring patching or other workarounds. Restate’s versioning strategy fits perfectly with AWS Lambda, allowing rapid iteration and deployment of new versions without breaking ongoing work.

  One major thing for us is the versioning of the Lambda functions... I really like Restate’s versioning strategy because you just deploy a new version and Restate and does everything for you.

  -- Stephan Gilli, Co-founder at Deliveru

The Results

Restate now powers Deliveru’s entire recruiting platform, serving recruiting agencies with thousands of recruiters and saving them countless hours on scanning, reading, and analyzing CVs to find eligible candidates.

Here are the key Restate features they use:

• Durable Execution: Orchestrates every workflow from candidate intake to transcription, including workflows that run for longer periods of time or wait for human input.
• AI Workflows: Complex 15-20 step workflows that call LLMs for document processing and analysis.
• Virtual Objects: Models candidates as exclusive entities to prevent duplicate messaging.
• Human-in-the-Loop Workflows: Restate's Durable Promises help implement resilient approval workflows where recruiters accept or reject candidate recommendations.
• Idempotency: Restate automatically guards against executing duplicate work. Making sure candidates are only processed once and that workflows execute exactly once.
• Asynchronous workflow result retrieval: For customers using their own systems (like SAP) instead of Deliveru's UI, Deliveru exposes Restate's attach API, allowing asynchronous retrieval of workflow results and status. This required no additional development from their side.
• Serverless deployment: Deliveru’s entire setup runs on AWS Lambda combined with Restate Cloud.

With a small team behind Deliveru, Restate made it possible for them to implement their use case with built-in resiliency, zero infrastructure management overhead, and while ensuring in-flight work never breaks.