GLM 5.3 Flash API Pricing
Z.ai (GLM) · context window 1.3M · prices updated 2026-09-15
Where GLM 5.3 Flash sits on price
At $0.5 per million output tokens, GLM 5.3 Flash is a mid tier model — 4.2× cheaper than the median output price of $2.08, which puts it cheaper than 79% and pricier than 21% of the models we track. It sits 3th cheapest of the 17 Z.ai (GLM) models we track. Output costs 3.3× input, the usual spread — trim both, starting with the answer length.
Cached input is 80% cheaper. On an input-heavy workload you need roughly a 31% cache-hit rate to take 25% off the input line — reachable for chatbots and agents that resend the same system prompt and history.
What real workloads cost on GLM 5.3 Flash
These three workloads are the ones teams actually run on a mid-priced model — a $0.5/1M model is not bought for the same job as one ten times the price.
| Workload | Per request | Per month |
|---|---|---|
| Support chatbot — 500 conversations/day (5K in / 1.4K out) Conversation history re-sent each turn — the classic prompt-caching win. | $0.0014 | $21.75 |
| Document pipeline — 10K docs/day (3K in / 500 out) Batch-friendly: no user waiting, so a ~50% batch discount usually applies. | $0.0007 | $210 |
| Long-context analysis — 200 runs/day (250K in / 4K out) Only possible on large-context models; input cost is nearly the whole bill. | $0.0395 | $237 |
Model your exact traffic in the API cost calculator — it preloads GLM 5.3 Flash with caching and batch options.
GLM 5.3 Flash price history
Z.ai (GLM) last raised GLM 5.3 Flash's output price on Sep 13, 2026 (+100% per output token), from $0.075/$0.25 to $0.15/$0.5 per 1M in/out. That is one of 3 repricings in the 18 days we have tracked it — worth knowing before you hard-code today's rate into a budget.
| Date | Input /1M | Output /1M | Output change |
|---|---|---|---|
| Aug 28, 2026 (tracking began) | $0.075 | $0.25 | — |
| Sep 10, 2026 | $0.15 | $0.5 | +100% |
| Sep 12, 2026 | $0.075 | $0.25 | -50% |
| Sep 13, 2026 | $0.15 | $0.5 | +100% |
Change-points from our daily price snapshots (tracking since Aug 28, 2026; intraday moves between snapshots are not captured).
GLM 5.3 Flash vs Qwen3 30B A3B
The closest-priced alternative from another vendor is Qwen3 30B A3B (Alibaba (Qwen)) — priced within a rounding error on output, with $0.03 less per million input tokens. When two models land this close on price, the decision is quality on your own workload, not the price sheet: run 50 real requests through both and compare.
See Qwen3 30B A3B pricing →Cheaper alternatives
More Z.ai (GLM) models
Frequently asked questions
› How much does the GLM 5.3 Flash API cost?
GLM 5.3 Flash costs $0.15 per million input tokens and $0.5 per million output tokens, with cached input at $0.03 per million (80% cheaper). That works out to roughly 2,000,000 output tokens per dollar.
› What does the support chatbot workload cost on GLM 5.3 Flash?
Support chatbot — 500 conversations/day (5K in / 1.4K out) costs about $0.0014 per request and $21.75 per month on GLM 5.3 Flash. Conversation history re-sent each turn — the classic prompt-caching win.
› What does it cost to fill GLM 5.3 Flash's 1.3M context window?
Sending 1.3M of input in a single request costs $0.1966 at $0.15 per million tokens — before any output. With prompt caching that same fill drops to about $0.0393 on repeat requests. This is why large context windows are cheap to advertise and expensive to actually use.
› Is GLM 5.3 Flash worth the price?
GLM 5.3 Flash sits in the middle of the market (3 of 17 by price within Z.ai (GLM)). The honest test is a routing experiment: send the same 200 real requests to this model and to a tier below, and compare failure rate against the price gap — most teams find a majority of traffic never needed the pricier model.