Vertex model API pricing
Vertex Gemini 3.1 Flash API pricing
Vertex Gemini 3.1 Flash API pricing is $0.500 per 1M input tokens and $3.00 per 1M output tokens in the ByteCosts provider pricing index. For an equal 1M input plus 1M output token plan, the listed token cost is $3.50. Context window: -. No source-backed prompt cache read/write price is published for this record. The confidence grade is A+: Read from the provider's official pricing page. The source was last checked 2026-07-19. At a reference workload of 1M input tokens and 250K output tokens per month, the listed token cost is $1.25 / month. This is a planning estimate; real invoices can differ because taxes, discounts, commitments, gateway fees, and non-token charges are excluded.
Open the pricing index - Vertex / Gemini 3.1 Flash →
Pricing snapshot
| Field | Value |
|---|---|
| Provider | Vertex |
| Model | Gemini 3.1 Flash |
| Input / 1M tokens | $0.500 |
| Output / 1M tokens | $3.00 |
| Cache read / 1M tokens | - |
| Cache write / 1M tokens | - |
| Cache write 1h / 1M tokens | - |
| Context window | - |
| Reference monthly workload | $1.25 / month |
The reference workload is 1M input tokens plus 250K output tokens per month. It excludes taxes, discounts, gateway fees, and non-token charges.
Reference workload examples
Each example is pure arithmetic from this committed record's input and output token prices. The assumptions are shown inline.
| Example | Assumed monthly tokens | Estimated token cost |
|---|---|---|
| Light reference | 1M input + 250K output tokens/month | $1.25 / month |
| Production reference | 10M input + 2.5M output tokens/month | $12.50 / month |
| Heavy reference | 100M input + 25M output tokens/month | $125 / month |
Examples exclude taxes, discounts, commitments, gateway fees, cache effects, and non-token charges unless those charges are part of the committed token price record.
When this model is cost-effective
Gemini 3.1 Flash ranks 2 of 6 Vertex records by combined list price ($3.50 for 1M input plus 1M output tokens). That puts it in the lower-priced third of this provider's committed records.
No source-backed cache-read discount is committed for this record, so the page does not assume cache savings.
No context window is committed for this record, so there is no long-context cost signal to apply.
Cheaper alternatives
These records have a lower committed input+output list price than this page's record. Same-provider records and same-model cross-provider records are preferred when available.
| Record | Input / 1M | Output / 1M | Combined / 1M + 1M | Detail page |
|---|---|---|---|---|
| Vertex Gemini 3 Flash Preview | $0.250 | $1.50 | $1.75 | /tools/ai-provider-pricing/google-vertex--gemini-3-flash-preview |
| Z.AI GLM-4.7-Flash | $0 | $0 | $0 | /tools/ai-provider-pricing/zai--glm-4.7-flash |
| Z.AI GLM-4.5-Flash | $0 | $0 | $0 | /tools/ai-provider-pricing/zai--glm-4.5-flash |
Evidence and freshness
ByteCosts grades this row A+. Read from the provider's official pricing page. The record was first tracked on 2026-05-30 and last checked on 2026-07-19.
The source URL is kept with the record so readers can verify the provider page before making a purchasing or architecture decision. Prices change often, so quote the last-checked date with any copied number.
Watch-outs
- image surcharge
- no prompt caching
Price history
| When | Field | Was | Now | Change |
|---|---|---|---|---|
| 2026-06-01 | imageOutput | new | $60.00 | new |
Frequently asked questions
Is Gemini 3.1 Flash free to use?
This ByteCosts row is not marked free. Use the listed token rates and verify the provider source for discounts, commitments, and account-specific terms.
Does this page include all possible charges?
No. The page focuses on source-backed token pricing and known cache/context fields. It does not include taxes, enterprise commitments, gateway markups, storage, retrieval, fine-tuning, or platform fees unless those charges are present in the source-backed row.
Vertex Gemini 3.1 Flash API pricing. ByteCosts. Updated 2026-07-19. https://bytecosts.com/tools/ai-provider-pricing/google-vertex--gemini-3.1-flash/