The best JSON libraries, according to hackers
3 JSON libraries were recommended on Hacker News between November 2025 and November 2026. We rank them by how many separate people recommend each one, and 1 earns the Hacker Approved badge.
Top pick
The most recommended JSON library with the badge. Each figure is one person. RecommendsCriticizes One comment
Parses gigabytes per second
Fast C++ JSON parser using SIMD, reaching gigabytes per second. Caveat: it still reads every byte, so there is no performance win when the whole input must be processed.
All 3 JSON libraries, ranked
Select a column heading to sort. Approval share is recommenders out of everyone who gave an opinion; the tick on each bar marks the 2 to 1 line the badge needs. Months counts the months, out of 13, in which someone recommended it.
| Rank | |||||||
|---|---|---|---|---|---|---|---|
| 1 | simdjson | 12 | 1 | 92% | 7 | — | Approved |
| 2 | Jackson FasterXML | 6 | 4 | 60% | 4 | — | — |
| 3 | System.Text.Json | 5 | 4 | 56% | 2 | — | — |
How we rank
Rank is the number of separate people who recommend a product in a Hacker News comment over the past year. Someone who praises the same JSON library in five threads counts once.
The badge goes to JSON libraries that at least 10 people recommend, with recommenders outnumbering critics at least 2 to 1, recommended in at least 4 of the 13 months.
Rankings are never for sale. We may earn a commission when you buy through our links. It never changes the order.