DeepSeek V4 Pro (Workers AI) vs Gemini 3.8 Flash
Gemini 3.8 Flash reads a 26.2K-token pull request for $0.0197, 43% less than DeepSeek V4 Pro (Workers AI) ($0.0346). From 2027-01-01, after a scheduled reprice, DeepSeek V4 Pro (Workers AI) becomes the cheaper one. Both sit in the mid-range price tier, so the choice between them is about review quality more than budget. The benchmark cannot separate their recall: DeepSeek V4 Pro (Workers AI) minus Gemini 3.8 Flash is −14 pts (95% interval −29 pts to 0 pts).
Side by side
| Figure | DeepSeek V4 Pro (Workers AI) | Gemini 3.8 Flash |
|---|---|---|
| Price tier | Mid-range | Mid-range |
| Bugs caughtshare of known bugs | 54% | 68% (better) |
| False alarmsper clean PR | 2.9 | 1.0 (better) |
| Cost per reviewmeasured | $0.0643 (better) | $0.0862 |
| Cost per bug caught | $0.0872 (better) | $0.1166 |
| Exact linecatches on the expected lines | 89% | 94% (better) |
| Review timemean | 390s (better) | 427s |
| Typical review calllist price | $0.0442 | $0.0287 (better) |
| Input / 1M tokens | $1.32 | $0.75 (better) |
| Output / 1M tokens | $3.96 | $3.75 (better) |
| Context window | 1M | 1M |
- From 2027-01-01, after a scheduled reprice, DeepSeek V4 Pro (Workers AI) is the cheaper of the two.
Head to head
The known bugs both were scored on, by who caught each in at least one run.
By language
| Model | All | TypeScript6 bugs | Go4 bugs | Java4 bugs | Rust4 bugs | C#3 bugs | JavaScript3 bugs | Kotlin3 bugs | PHP3 bugs | Python3 bugs | Ruby3 bugs | Swift3 bugs | C++2 bugs | C1 bug |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| DeepSeek V4 Pro (Workers AI) | 54% | 79% | 25% | 49% | 54% | 59% | 17% | 30% | 69% | 72% | 67% | 75% | 38% | 33% |
| Gemini 3.8 Flash | 68% | 83% | 75% | 43% | 75% | 78% | 67% | 0% | 50% | 83% | 100% | 100% | 50% | 50% |
Of the 42 known bugs both were scored on, both caught 25 and neither caught 2. DeepSeek V4 Pro (Workers AI) caught 9 bugs that Gemini 3.8 Flash missed: 3 in Kotlin, 2 in Java, 1 in C++, 1 in JavaScript, 1 in PHP and 1 in Rust. Gemini 3.8 Flash caught 6 bugs that DeepSeek V4 Pro (Workers AI) missed: 2 in Go, 2 in JavaScript, 1 in C# and 1 in Rust.
On pull requests with no known bug, DeepSeek V4 Pro (Workers AI) raised 2.9 false alarms per review and Gemini 3.8 Flash 1. A measured review cost $0.0643 on DeepSeek V4 Pro (Workers AI), 25% less than $0.0862 on Gemini 3.8 Flash.
| Pull request | Language · kind | DeepSeek V4 Pro (Workers AI) | Gemini 3.8 Flash |
|---|---|---|---|
| nushell/nushellreorganize nushell configuration | Rust · Error handling | 3/4 | 0/1 |
| jhy/jsoupStore cached child els in Attributes, not field | Java · Concurrency | 3/6 | 0/4 |
| kotest/kotestFix DataClassEq comparator | Kotlin · Logic | 2/4 | 0/1 |
| nodejs/undicifeat: add configurable maxPayloadSize for WebSocket | JavaScript · Security | 2/4 | 0/1 |
| symfony/symfony[Security] Allow multiple OIDC discovery endpoints | PHP · Security | 1/3 | 0/1 |
| ggml-org/llama.cpprpc : cache and reuse compute graphs | C++ · Security | 1/4 | 0/1 |
| kotest/kotestRefactor eventually to ensure wall-clock time usage | Kotlin · Error handling | 1/4 | 0/1 |
| mockito/mockitoAdd core API to enable Kotlin singleton mocking | Java · API misuse | 1/5 | 0/1 |
| ktorio/ktorKTOR-9171 Redesign ByteReadChannel.readUTF8Line API | Kotlin · Logic | 1/7 | 0/1 |
| denoland/denoperf(libs/core): poll only ready handles and yield between I/O batches | Rust · Concurrency | 0/4 | 1/1 |
| dotnet/orleansfix(serialization): cap codec allocations | C# · Logic | 0/4 | 1/1 |
| go-chi/chifeat: middleware.ClientIP, a replacement for middleware.RealIP | Go · Security | 0/4 | 1/1 |
| golang/gocrypto/tls: add LocalCertificate to ConnectionState | Go · Logic | 0/4 | 2/2 |
| pinojs/thread-streamrefactor: replace setTimeout with Atomics.waitAsync | JavaScript · Concurrency | 0/4 | 2/2 |
| sindresorhus/p-throttleAdd `weight` option | JavaScript · Logic | 0/4 | 1/1 |
Defects caught over all runs: a PR reviewed three times with one known bug shows 3/3 when it was caught every time.
Every bug each was scored on: DeepSeek V4 Pro (Workers AI) and Gemini 3.8 Flash.