simdjson
Hacker ApprovedThe most recommended of 3 JSON libraries
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.
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.
13 people gave an opinion
- recommend it
- 12
- criticize it
- 1
- approval share
- 92%
Recommended in 7 of 13 months
- November 2025: not recommended
- December 2025: not recommended
- January 2026: recommended
- February 2026: recommended
- March 2026: recommended
- April 2026: not recommended
- May 2026: not recommended
- June 2026: recommended
- July 2026: recommended
- August 2026: not recommended
- September 2026: recommended
- October 2026: recommended
- November 2026: not recommended (month in progress)
Why it carries the badge
- 12 people recommend itNeeds 10 or more, met.
- 12 recommenders for every criticNeeds 2 to 1 or better, met.
- Recommended in 7 of 13 monthsNeeds 4 or more, met.
The same three rules apply to every product, and the badge can’t be bought. How the badge works
What people say about it
The reasons people give, with the number of comments that give each one. Open a reason to read what they said.
Why people recommend it
Each mark is one comment
Parses gigabytes per second
“You can parse JSON at several GB/s”
Comment from 19 Jan 2026 in “Command-line Tools can be 235x Faster than your Hadoop Cluster (2014)” “can process gigabytes per second”
Comment from 20 Mar 2026 in “We rewrote our Rust WASM Parser in TypeScript – and it got 3x Faster” Sparse access via ondemand API
“take simdjson, use its ondemand api and then navigate it with .at_path(_with_wildcard)”
Comment from 27 Mar 2026 in “A Faster Alternative to Jq” “It parses fast with SIMDJSON or doing various other approaches to parse sparsely.”
Comment from 18 Oct 2026 in “A skeptic's first contact with Kubernetes (2024)”
What people warn about
Each mark is one comment
No gain when whole input is read
“But, if the application really needs to process every piece of the entire input, there's no performance win.”
Comment from 23 Jul 2026 in “Everyone Should Know SIMD” “Which is great, but a JSON parser fundamentally can't avoid looking at every byte.”
Comment from 6 Jan 2026 in “I/O is no longer the bottleneck? (2022)”
Other JSON libraries people recommend
The two most recommended other JSON libraries, with the same counts for each, so you can compare like for like. The tick on each bar marks the 2 to 1 line the badge needs.
| Product | Recommend | Criticize | Approval | Months | Owned | Badge |
|---|---|---|---|---|---|---|
| simdjsonThis page | 12 | 1 | 92% | 7 | — | Approved |
| Jackson FasterXML | 6 | 4 | 60% | 4 | — | — |
| System.Text.Json | 5 | 4 | 56% | 2 | — | — |
What people said
10 of the 13 comments that mention it, newest first. Each links to the original comment.
“It parses fast with SIMDJSON or doing various other approaches to parse sparsely.”
“Daniel Lemire (of simdjson”
“It showcases an especially ingenious scheme for escaping json strings”
“But, if the application really needs to process every piece of the entire input, there's no performance win.”
“take simdjson, use its ondemand api and then navigate it with .at_path(_with_wildcard)”
“can process gigabytes per second”
“seems it is not there natively in Python,but seems cool”
“You can parse JSON at several GB/s”
“Which is great, but a JSON parser fundamentally can't avoid looking at every byte.”
“any usage of it breaks std::unordered_map in unrelated parts of the code”
Counts come from 1,795,640 Hacker News comments, November 2025 to November 2026. How we count. Report a mistake.