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Google·Software Engineer·Onsite - System Design / Architecture·Senior

SeniorPrefer not to say
May 2026

Summary

Got a system design question for a Google role that was basically 'design the database behind Google Translate.' Not a ton of context given, just that one question and you figure it out from there.

Questions Asked (1)

Q1

How would you design a database to support a translation service like Google Translate?

System DesignData ModelingTechnical Trade-offs
Author's notes

I started by asking clarifying questions about scale and use cases, which felt right, but then I kind of froze on the schema side.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the scope and requirements of the translation service, such as the languages supported, expected query volume, latency requirements, and whether it's for text or speech. Then, propose a high-level data model that separates static linguistic data (e.g., dictionaries, language models) from dynamic data (e.g., user queries, translations), and discuss storage choices (SQL vs NoSQL, caching, etc.) with trade-offs. Finally, dive into how you would handle scale, consistency, and performance.

Pro tip: Emphasize the importance of caching frequent translations and using a distributed, sharded database to handle Google-scale traffic, and mention that you would consider using a combination of relational and NoSQL databases for different data types.

1. Clarify Requirements

Ask questions to understand the scale, latency, consistency, and features needed (e.g., number of languages, real-time translation, offline support).

2. High-Level Data Model

Outline the main entities: languages, phrases, translations, user queries, and possibly language models. Define relationships and access patterns.

3. Storage Choices

Choose appropriate databases for each entity: e.g., a relational DB for language pairs and dictionaries, a NoSQL store for user logs, and a distributed cache for frequent translations.

4. Scalability and Performance

Discuss sharding, replication, indexing, and caching strategies to handle high read throughput and low latency. Mention trade-offs between consistency and availability.

5. Trade-offs and Alternatives

Summarize key trade-offs (e.g., SQL vs NoSQL, normalized vs denormalized) and justify your choices based on the requirements.

Key Points to Mention

  • Sharding by language pair or user region to distribute load
  • Caching frequently requested translations (e.g., using Redis or Memcached)
  • Using a graph database for language relationships or a columnar store for analytics
  • Handling consistency: eventual consistency for user logs vs strong consistency for dictionary updates
  • Data partitioning and replication for fault tolerance and low latency
  • Considering machine learning models for translation and how to store/update them

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.