Question 1

Poison vs Jason: which is better for Elixir?

Accepted Answer

Poison often benchmarks faster due to its optimized parser, but Jason is more widely adopted with better community support. Choose Poison if speed is critical, but consider Jason for broader ecosystem compatibility.

Question 2

How to encode only specific fields from a struct with Poison?

Accepted Answer

Derive Poison.Encoder with the :only option, e.g., @derive {Poison.Encoder, only: [:name]}. This lets you select which attributes to include in the JSON output, as shown in the README.

Question 3

Does Poison support JSON streaming?

Accepted Answer

No, Poison does not mention streaming support in its README. It's designed for in-memory processing, so for large datasets, you may need alternative libraries or manual chunking.

Question 4

How to handle duplicate keys in JSON with Poison?

Accepted Answer

Pass strict_keys: true when encoding to enforce validation and raise an error on duplicate keys. This aligns with RFC recommendations but adds a performance cost.

Question 5

Is Poison safe to use with atom keys?

Accepted Answer

Use keys: :atoms cautiously, as it creates non-garbage-collected atoms that can crash the VM. The README recommends avoiding it unless you pre-allocate atoms or use string keys instead.

Question 6

What are Poison's performance trade-offs?

Accepted Answer

Poison sacrifices some safety features like automatic atom handling for speed. Enabling strict key validation or using atom keys can reduce performance or increase memory risks.

poison

What is poison?

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